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ART002030076
|
oai_dc
|
Design of a TMD solution to mitigate wind-induced local vibrations in an existing timber footbridge
|
Design of a TMD solution to mitigate wind-induced local vibrations in an existing timber footbridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Daniele Bortoluzzi(University of Pavia); Sara Casciati(University of Catania at Siracusa); Lorenzo Elia(University of Pavia); Lucia Faravelli(University of Pavia)"
] |
The design of a passive control solution based on tuned mass dampers (TMD’s) requires the estimation of the actual masses involved in the undesired vibration. This task may result not so straightforward as expected when the vibration resides in subsets of different structural components. This occurs, for instance, when the goal is to damp out vibrations on stays. The theoretical aspects are first discussed and a design process is formulated. For sake of exemplification, a multiple TMD’s configurations is eventually conceived for an existing timber footbridge located in the municipality of Trasaghis (North-Eastern Italy). The bridge span is 83 m and the deck width is 3.82 m.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002030073
|
oai_dc
|
A developed hybrid method for crack identification of beams
|
A developed hybrid method for crack identification of beams
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ali. R. Vosoughi(Shiraz University)"
] |
A developed hybrid method for crack identification of beams is presented. Based on the Euler-Bernouli beam theory and concepts of fracture mechanics, governing equation of the cracked beams is reformulated. Finite element (FE) method as a powerful numerical tool is used to discritize the equation in space domain. After transferring the equations from time domain to frequency domain, frequencies and mode shapes of the beam are obtained. Efficiency of the governed equation for free vibration analysis of the beams is shown by comparing the results with those available in literature and via ANSYS software. The used equation yields to move the influence of cracks from the stiffness matrix to the mass matrix. For crack identification measured data are produced by applying random error to the calculated frequencies and mode shapes. An objective function is prepared as root mean square error between measured and calculated data.
To minimize the function, hybrid genetic algorithms (GAs) and particle swarm optimization (PSO) technique is introduced. Efficiency, Robustness, applicability and usefulness of the mixed optimization numerical tool in conjunction with the finite element method for identification of cracks locations and depths are shown via solving different examples.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002030075
|
oai_dc
|
Perturbation analysis for robust damage detection with application to multifunctional aircraft structures
|
Perturbation analysis for robust damage detection with application to multifunctional aircraft structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rafik Hajrya(Arts et Métiers ParisTech (ENSAM)); Nazih Mechbala(Arts et Métiers ParisTech (ENSAM))"
] |
The most widely known form of multifunctional aircraft structure is smart structures for structural health monitoring (SHM). The aim is to provide automated systems whose purposes are to identify and to characterize possible damage within structures by using a network of actuators and sensors.
Unfortunately, environmental and operational variability render many of the proposed damage detection methods difficult to successfully be applied. In this paper, an original robust damage detection approach using output-only vibration data is proposed. It is based on independent component analysis and matrix perturbation analysis, where an analytical threshold is proposed to get rid of statistical assumptions usually performed in damage detection approach. The effectiveness of the proposed SHM method is demonstrated numerically using finite element simulations and experimentally through a conformal load-bearing antenna structure and composite plates instrumented with piezoelectric ceramic materials
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002030079
|
oai_dc
|
Dynamic and static structural displacement measurement using backscattering DC coupled radar
|
Dynamic and static structural displacement measurement using backscattering DC coupled radar
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Shanyue Guan(University of Florida); Jennifer A. Rice(University of Florida); Changzhi Li(Texas Tech University); Yiran Li(Texas Tech University); Guochao Wang(Texas Tech University)"
] |
Vibration-based monitoring is one approach used to perform structural condition assessment.
By measuring structural response, such as displacement, dynamic characteristics of a structure may be estimated. Often, the primary dynamic responses in civil structures are below 5 Hz, making accurate low frequency measurement critical for successful dynamic characterization. In addition, static deflection measurements are useful for structural capacity and load rating assessments. This paper presents a DC coupled continuous wave radar to accurately detect both dynamic and static displacement. This low-cost radar sensor provides displacement measurements within a compact, wireless unit appropriate for a range of structural monitoring applications. The hardware components and operating mechanism of the radar are introduced and a series of laboratory experiments are presented to assess the performance characteristics of the radar. The laboratory and field experiments investigate the effect of factors such as target distance, motion amplitude, and motion frequency on the radar’s measurement accuracy. The results demonstrate that the radar is capable of both static and dynamic displacement measurements with sub-millimeter accuracy, making it a promising technology for structural health monitoring.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002030080
|
oai_dc
|
Pyroeffects on magneto-electro-elastic sensor bonded on mild steel cylindrical shell
|
Pyroeffects on magneto-electro-elastic sensor bonded on mild steel cylindrical shell
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"P. Kondaiah(Mahindra É cole Centrale); K. Shankar(Indian Institute of Technology Madras); N. Ganesan(Indian Institute of Technology Madras)"
] |
Magneto-electro-elastic (MEE) materials under thermal environment exhibits pyroelectric and pyromagnetic coefficients resulting in pyroeffects such as pyroelectric and pyromagnetic. The pyroeffects on the behavior of multiphase MEE sensor bonded on top surface of a mild steel cylindrical shell under thermal environment is presented in this paper. The study aims to investigate how samples having different volume fractions of the multiphase MEE sensor behave due to pyroeffects using semi-analytical finite element method. This is studied at an optimal location on a mild steel cylindrical shell, where the maximum electric and magnetic potentials are induced due to these pyroeffects under different boundary conditions. It is assumed that sensor and shell is perfectively bonded to each other. The maximum pyroeffects on electric and magnetic potentials are observed when volume fraction is vf = 0.2. Additionally, the boundary conditions significantly influence the pyroeffects on electric and magnetic potentials.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002030074
|
oai_dc
|
A strain-based wire breakage identification algorithm for unbonded PT tendons
|
A strain-based wire breakage identification algorithm for unbonded PT tendons
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A.B.M. Abdullah(University of Florida); Jennifer A. Rice(University of Florida); H.R. Hamilton(University of Florida)"
] |
Tendon failures in bonded post-tensioned bridges over the last two decades have motivated ongoing investigations on various aspects of unbonded tendons and their monitoring methods. Recent research shows that change of strain distribution in anchor heads can be useful in detecting wire breakage in unbonded construction. Based on this strain variation, this paper develops a damage detection model that enables an automated tendon monitoring system to identify and locate wire breaks. The first part of this paper presents an experimental program conducted to study the strain variation in anchor heads by generating wire breaks using a mechanical device. The program comprised three sets of tests with fully populated 19-strand anchor head and evaluated the levels of strain variation with number of wire breaks in different strands. The sensitivity of strain variation with wire breaks in circumferential and radial directions of anchor head in addition to the axial direction (parallel to the strand) were investigated and the measured axial strains were found to be the most sensitive. The second part of the paper focuses on formulating the wire breakage detection framework. A finite element model of the anchorage assembly was created to demonstrate the algorithm as well as to investigate the asymmetric strain distribution observed in experimental results. In addition, as almost inevitably encountered during tendon stressing, the effects of differential wedge seating on the proposed model have been analyzed. A sensitivity analysis has been performed at the end to assess the robustness of the model with random measurement errors.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002030078
|
oai_dc
|
Fuzzy modelling approach for shear strength prediction of RC deep beams
|
Fuzzy modelling approach for shear strength prediction of RC deep beams
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mohammad Mohammadhassani(University of Malaya); Aidi MD. Saleh(Malaysian public work department); M Suhatril(University of Malaya); M. Safa(University of Malaya)"
] |
This study discusses the use of Adaptive-Network-Based-Fuzzy-Inference-System (ANFIS) in predicting the shear strength of reinforced-concrete deep beams. 139 experimental data have been collected from renowned publications on simply supported high strength concrete deep beams. The results show that the ANFIS has strong potential as a feasible tool for predicting the shear strength of deep beams within the range of the considered input parameters. ANFIS‟s results are highly accurate, precise and therefore, more satisfactory. Based on the Sensitivity analysis, the shear span to depth ratio (a/d) and concrete cylinder strength ( c f′) have major influence on the shear strength prediction of deep beams. The parametric study confirms the increase in shear strength of deep beams with an equal increase in the concrete strength and decrease in the shear span to-depth-ratio.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002030081
|
oai_dc
|
A SMA-based morphing flap: conceptual and advanced design
|
A SMA-based morphing flap: conceptual and advanced design
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Salvatore Ameduri(Centro Italiano Ricerche Aerospaziali); Antonio Concilio(Centro Italiano Ricerche Aerospaziali); Rosario Pecora(Università degli Studi di Napoli Federico II)"
] |
In the work at hand, the development of a morphing flap, actuated through shape memory alloy load bearing elements, is described. Moving from aerodynamic specifications, prescribing the morphed shape enhancing the aerodynamic efficiency of the flap, a suitable actuation architecture was identified, able to affect the curvature. Each rib of the flap was split into three elastic elements, namely “cells”, connected each others in serial way and providing the bending stiffness to the structure. The edges of each cell are linked to SMA elements, whose contraction induces rotation onto the cell itself with an increase of the local curvature of the flap airfoil. The cells are made of two metallic plates crossing each others to form a characteristic “X” configuration; a good flexibility and an acceptable stress concentration level was obtained non connecting the plates onto the crossing zone. After identifying the main design parameters of the structure (i.e. plates relative angle, thickness and depth, SMA length, cross section and connections to the cell) an optimization was performed, with the scope of enhancing the achievable rotation of the cell, its ability in absorbing the external aerodynamic loads and, at the same time, containing the stress level and the weight. The conceptual scheme of the architecture was then reinterpreted in view of a practical realization of the prototype. Implementation issues (SMA - cells connection and cells relative rotation to compensate the impressed inflection assuring the SMA pre-load) were considered. Through a detailed FE model the prototype morphing performance were investigated in presence of the most severe load conditions.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002030072
|
oai_dc
|
An original device for train bogie energy harvesting: a real application scenario
|
An original device for train bogie energy harvesting: a real application scenario
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Francesco Amoroso(University of Napoli Federico II); Rosario Pecora(University of Napoli Federico II); Monica Ciminello(C.I.R.A.- Italian Aerospace Research Center); Antonio Concilio(C.I.R.A.- Italian Aerospace Research Center)"
] |
Today, as railways increase their capacity and speeds, it is more important than ever to be completely aware of the state of vehicles fleet‟s condition to ensure the highest quality and safety standards, as well as being able to maintain the costs as low as possible. Operation of a modern, dynamic and efficient railway demands a real time, accurate and reliable evaluation of the infrastructure assets, including signal networks and diagnostic systems able to acquire functional parameters. In the conventional system, measurement data are reliably collected using coaxial wires for communication between sensors and the repository. As sensors grow in size, the cost of the monitoring system can grow. Recently, auto-powered wireless sensor has been considered as an alternative tool for economical and accurate realization of structural health monitoring system, being provided by the following essential features: on-board micro-processor, sensing capability, wireless communication, auto-powered battery, and low cost. In this work, an original harvester device is designed to supply wireless sensor system battery using train bogie energy. Piezoelectric materials have in here considered due to their established ability to directly convert applied strain energy into usable electric energy and their relatively simple modelling into an integrated system. The mechanical and electrical properties of the system are studied according to the project specifications. The numerical formulation is implemented with in-house code using commercial software tool and then experimentally validated through a proof of concept setup using an excitation signal by a real application scenario.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002030077
|
oai_dc
|
A finite element analysis of a new design of a biomimetic shape memory alloy artificial muscle
|
A finite element analysis of a new design of a biomimetic shape memory alloy artificial muscle
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Moez Ben Jaber(University of Carthage); Mohamed A. Trojette(University of Tunis); Fehmi Najar(University of Carthage)"
] |
In this work, a novel artificial circular muscle based on shape memory alloy (S.M.A.) is proposed. The design is inspired from the natural circular muscles found in certain organs of the human body such as the small intestine. The heating of the prestrained SMA artificial muscle will induce its contraction. In order to measure the mechanical work provided in this case, the muscle will be mounted on a silicone rubber cylindrical tube prior to heating. After cooling, the reaction of the rubber tube will involve the return of the muscle to its prestrained state. A finite element model of the new SMA artificial muscle was built using the software "ABAQUS". The SMA thermomechanical behavior law was implemented using the user subroutine "UMAT". The numerical results of the finite element analysis of the SMA muscle are presented to shown that the proposed design is able to mimic the behavior of a natural circular muscle
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001982939
|
oai_dc
|
The study on piezoelectric transducers: theoretical analysis and experimental verification
|
The study on piezoelectric transducers: theoretical analysis and experimental verification
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chia-Chung Sung(National Cheng-Kung University); Szu-Chi Tien(National Cheng-Kung University)"
] |
The main purpose of this research is to utilize simple mathematical models to depict thevibration behavior and the resulted sound field of a piezoelectric disk for ultrasonic transducers. Instead ofusing 1-D vibration model, coupled effect between the thickness and the radial motions was considered to beclose to the real vibration behavior. Moreover, Huygens-Fresnel principle was used in both incident andreflected waves to analyze the sound field under obstacles in finite distance. Results of the testedpiezoelectric disk show that, discrepancies between the simulation and experiment are 2.5% for resonantfrequency and 12% for resulted sound field. Therefore, the proposed method can be used to reduce thecomplexity in modeling vibration problems, and increase the reliability on analyzing piezoeletric transducersin the design stage.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001982930
|
oai_dc
|
Design of intelligent control strategies using a magnetorheological damper for span structure
|
Design of intelligent control strategies using a magnetorheological damper for span structure
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ángela Hernández(Universidad de La Laguna); Graciliano N. Marichal(Universidad de La Laguna); Alfonso V. Poncela(Universidad de Valladolid); Isidro Padrón(Universidad de La Laguna)"
] |
This paper focuses on the design of an intelligent control system. The used techniques are basedon Neuro Fuzzy approaches applied to a magnetorheological damper in order to reduce the vibrations overfootbridges; it has been applied to the Science Museum Footbridge of Valladolid, particularly. A model ofthe footbridge and of the damper has been built using different simulation tools, and a successful comparisonwith the real footbridge and the real damper has been carried out. This simulated model has allowed thereproduction of the behaviour of the footbridge and damper when a pedestrian walks across the footbridge.
Once it is determined that the simulation results are similar to real data, the control system is introduced intothe model. In this sense, different strategies based on Neuro Fuzzy systems have been studied. In fact, anANFIS (Artificial Neuro Fuzzy Inference System) method has also been used, in addition to an alternativeNeuro Fuzzy approach. Several trials have been carried out, using both techniques, obtaining satisfactoryresults after using these techniques.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001982931
|
oai_dc
|
Analytical testing and evaluation of truss typed structures for tunnel maintenance
|
Analytical testing and evaluation of truss typed structures for tunnel maintenance
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"이동규(세종대학교); Dohwan Kim(Research Institute of Industrial Science and Technology); 이재홍(세종대학교); Pilsung Noh(Yujin Engineering and Construction); 박성수(부산대학교)"
] |
The goal of this study is to present numerical modeling and analytical testing in order to evaluatean innovative space truss typed temporary structure, which is used to maintenance and repair of road tunnels.
The present space truss structure has merits to use UL-700 high strength steel tube as members and to carryout maintenance and repair works of road tunnels without blocking cars and transportations. Numericalmodeling and analytical testing of the space truss are investigated by using commercial engineering software,i.e., ABAQUS 6.5-1, and then it is verified that the truss structure has both structural safety and effectivefunction for maintenances and repairs of road tunnels.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001982962
|
oai_dc
|
Characterization and modeling of a self-sensing MR damper under harmonic loading
|
Characterization and modeling of a self-sensing MR damper under harmonic loading
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Z.H. Chen(Fuzhou University); Y.Q. Ni(The Hong Kong Polytechnic University); S.W. Or(The Hong Kong Polytechnic University)"
] |
A self-sensing magnetorheological (MR) damper with embedded piezoelectric force sensor hasrecently been devised to facilitate real-time close-looped control of structural vibration in a simple andreliable manner. The development and characterization of the self-sensing MR damper are presented basedon experimental work, which demonstrates its reliable force sensing and controllable damping capabilities.
With the use of experimental data acquired under harmonic loading, a nonparametric dynamic model isformulated to portray the nonlinear behaviors of the self-sensing MR damper based on NARX modeling andneural network techniques. The Bayesian regularization is adopted in the network training procedure toeschew overfitting problem and enhance generalization. Verification results indicate that the developedNARX network model accurately describes the forward dynamics of the self-sensing MR damper and hassuperior prediction performance and generalization capability over a Bouc-Wen parametric model.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001982934
|
oai_dc
|
Detection of flexural damage stages for RC beams using Piezoelectric sensors (PZT)
|
Detection of flexural damage stages for RC beams using Piezoelectric sensors (PZT)
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chris G. Karayannis(Democritus University of Thrace); Maristella E. Voutetaki(Technical University of Crete); Constantin E. Chalioris(Democritus University of Thrace); Costas P. Providakis(Technical University of Crete); Georgia M. Angeli(Democritus University of Thrace)"
] |
Structural health monitoring along with damage detection and assessment of its severity level innon-accessible reinforced concrete members using piezoelectric materials becomes essential since engineersoften face the problem of detecting hidden damage. In this study, the potential of the detection of flexuraldamage state in the lower part of the mid-span area of a simply supported reinforced concrete beam usingpiezoelectric sensors is analytically investigated. Two common severity levels of flexural damage areexamined: (i) cracking of concrete that extends from the external lower fiber of concrete up to the steelreinforcement and (ii) yielding of reinforcing bars that occurs for higher levels of bending moment and afterthe flexural cracking. The purpose of this investigation is to apply finite element modeling using admittancebased signature data to analyze its accuracy and to check the potential use of this technique to monitorstructural damage in real-time. It has been indicated that damage detection capability greatly depends on thefrequency selection rather than on the level of the harmonic excitation loading. This way, the excitationloading sequence can have a level low enough that the technique may be considered as applicable andeffective for real structures. Further, it is concluded that the closest applied piezoelectric sensor to theflexural damage demonstrates higher overall sensitivity to structural damage in the entire frequency band forboth damage states with respect to the other used sensors. However, the observed sensitivity of the othersensors becomes comparatively high in the peak values of the root mean square deviation index.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001982945
|
oai_dc
|
Probabilistic-based damage identification based on error functions with an autofocusing feature
|
Probabilistic-based damage identification based on error functions with an autofocusing feature
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rahim Gorgin(Dalian University of Technology); Yunlong Ma(Beijing Aerospace System Engineering Institute); Zhanjun Wu(Dalian University of Technology); Dongyue Gao(Dalian University of Technology); Yishou Wang(Dalian University of Technology)"
] |
This study presents probabilistic-based damage identification technique for highlightingdamage in metallic structures. This technique utilizes distributed piezoelectric transducers to generate andmonitor the ultrasonic Lamb wave with narrowband frequency. Diagnostic signals were used to define thescatter signals of different paths. The energy of scatter signals till different times were calculated by takingroot mean square of the scatter signals. For each pair of parallel paths an error function based on the energyof scatter signals is introduced. The resultant error function then is used to estimate the probability of thepresence of damage in the monitoring area. The presented method with an autofocusing feature is applied toaluminum plates for method verification. The results identified using both simulation and experimentalLamb wave signals at different central frequencies agreed well with the actual situations, demonstrating thepotential of the presented algorithm for identification of damage in metallic structures. An obvious merit ofthe presented technique is that in addition to damages located inside the region between transducers; thosewho are outside this region can also be monitored without any interpretation of signals. This noveltyqualifies this method for online structural health monitoring.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001982949
|
oai_dc
|
Temperature effect on wireless impedance monitoring in tendon anchorage of prestressed concrete girder
|
Temperature effect on wireless impedance monitoring in tendon anchorage of prestressed concrete girder
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"박재형(부경대학교); Thanh-Canh Huynh(Pukyong National University); 김정태(부경대학교)"
] |
In this study, the effect of temperature variation on the wireless impedance monitoring isanalyzed for the tendon-anchorage connection of the prestressed concrete girder. Firstly, three impedancefeatures, which are peak frequency, root mean square deviation (RMSD) index, and correlation coefficient(CC) index, are selected to estimate the effects of temperature variation and prestress-loss on impedancesignatures. Secondly, wireless impedance tests are performed on the tendon-anchorage connection for whicha series of temperature variation and prestress-loss events are simulated. Thirdly, the effect of temperaturevariation on impedance signatures measured from the tendon-anchorage connection is estimated by the threeimpedance features. Finally, the effect of prestress-loss on impedance signatures is also estimated by thethree impedance features. The relative effects of temperature variation and prestress-loss are comparativelyexamined.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001982938
|
oai_dc
|
Optimal placement of piezoelectric actuators and sensors on a smart beam and a smart plate using multi-objective genetic algorithm
|
Optimal placement of piezoelectric actuators and sensors on a smart beam and a smart plate using multi-objective genetic algorithm
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Tamara Nestorović(Mechanics of Adaptive Systems Universitätsstr); Miroslav Trajkov(Mechanics of Adaptive Systems Universitätsstr); Seyedmehdi Garmabi(Mechanics of Adaptive Systems Universitätsstr)"
] |
In this paper a method of finding optimal positions for piezoelectric actuators and sensors ondifferent structures is presented. The genetic algorithm and multi-objective genetic algorithm are selected foroptimization and H∞ norm is defined as a cost function for the optimization process. To optimize theplacement concerning the selected modes simultaneously, the multi-objective genetic algorithm is used. Theoptimization is investigated for two different structures: a cantilever beam and a simply supported plate.
Vibrating structures are controlled in a closed loop with feedback gains, which are obtained using optimalLQ control strategy. Finally, output of a structure with optimized placement is compared with the output ofthe structure with an arbitrary, non-optimal placement of piezoelectric patches.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001982935
|
oai_dc
|
Development and application of construction monitoring system for Shanghai Tower
|
Development and application of construction monitoring system for Shanghai Tower
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Han Li(The Tongji University); Qi-lin Zhang(The Tongji University); Bin Yang(The Tongji University); Jia Lu(The Tongji University); Jia Hu(The Tongji University)"
] |
Shanghai Tower is a composite structure building with a height of 632 m. In order to verify thestructural properties and behaviors in construction and operation, a structural health monitoring project wasconducted by Tongji University. The monitoring system includes sensor system, data acquisition system anda monitoring software system. Focusing on the health monitoring in construction, this paper introduced themonitoring parameters in construction, the data acquisition strategy and an integration structural healthmonitoring (SHM) software. The integration software - Structural Monitoring/ Analysis/ Evaluation System(SMAE) is designed based on integration and modular design idea, which includes on-line data acquisition,finite elements and dynamic property analysis functions. With the integration and modular design idea, thisSHM system can realize the data exchange and results comparison from on-site monitoring and FEMeffectively. The analysis of the monitoring data collected during the process of construction shows that thesystem works stably, realize data acquirement and analysis effectively, and also provides measured basis forunderstanding the structural state of the construction. Meanwhile, references are provided for the futureautomates construction monitoring and implementation of high-rise building structures.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001982941
|
oai_dc
|
Characterization of railway substructure using a hybrid cone penetrometer
|
Characterization of railway substructure using a hybrid cone penetrometer
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yong-Hoon Byun(Korea University); Won-Taek Hong(Korea University); 이종섭(고려대학교)"
] |
Changes in substructure conditions, such as ballast fouling and subgrade settlement may causethe railway quality deterioration, including the differential geometry of the rails. The objective of this studyis to develop and apply a hybrid cone penetrometer (HCP) to characterize the railway substructure. The HCPconsists of an outer rod and an inner mini cone, which can dynamically and statically penetrate the ballastand the subgrade, respectively. An accelerometer and four strain gauges are installed at the head of the outerrod and four strain gauges are attached at the tip of the inner mini cone. In the ballast, the outer rod providesa dynamic cone penetration index (DCPI) and the corrected DCPI (CDCPI) with the energy transferred intothe rod head. Then, the inner mini cone is pushed to estimate the strength of the subgrade from the cone tipresistance. Laboratory application tests are performed on the specimen, which is prepared with gravel andsandy soil. In addition, the HCP is applied in the field and compared with the standard dynamic conepenetration test. The results from the laboratory and the field tests show that the cone tip resistance isinversely proportional to the CDCPI. Furthermore, in the subgrade, the HCP produces a high-resolutionprofile of the cone tip resistance and a profile of the CDCPI in the ballast. This study suggests that thedynamic and static penetration tests using the HCP may be useful for characterizing the railway substructure.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001982947
|
oai_dc
|
PCA-based neuro-fuzzy model for system identification of smart structures
|
PCA-based neuro-fuzzy model for system identification of smart structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Soroush Mohammadzadeh(Worcester Polytechnic Institute); Yeesock Kim(Worcester Polytechnic Institute); 안재훈(부산대학교)"
] |
This paper proposes an efficient system identification method for modeling nonlinear behaviorof civil structures. This method is developed by integrating three different methodologies: principalcomponent analysis (PCA), artificial neural networks, and fuzzy logic theory, hence named PANFIS(PCA-based adaptive neuro-fuzzy inference system). To evaluate this model, a 3-story building equippedwith a magnetorheological (MR) damper subjected to a variety of earthquakes is investigated. To train theinput-output function of the PANFIS model, an artificial earthquake is generated that contains a variety ofcharacteristics of recorded earthquakes. The trained model is also validated using the1940 El-Centro, Kobe,Northridge, and Hachinohe earthquakes. The adaptive neuro-fuzzy inference system (ANFIS) is used as abaseline. It is demonstrated from the training and validation processes that the proposed PANFIS model iseffective in modeling complex behavior of the smart building. It is also shown that the proposed PANFISproduces similar performance with the benchmark ANFIS model with significant reduction ofcomputational loads.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001982932
|
oai_dc
|
Shaking table testing of a steel frame structure equipped with semi-active MR dampers: comparison of control algorithms
|
Shaking table testing of a steel frame structure equipped with semi-active MR dampers: comparison of control algorithms
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"N. Caterino(Università degli Studi di Napoli Parthenope); M. Spizzuoco(Università degli Studi di Napoli Federico II); A. Occhiuzzi(Università degli Studi di Napoli Parthenope)"
] |
The effectiveness of the various control algorithms for semi-active structural control systemsproposed in the literature is highly questionable when dealing with earthquake actions, which never reach asteady state. From this perspective, the paper summarizes the results of an experimental activity aimed tocompare the effectiveness of four different semi-active control algorithms on a structural mock uprepresentative of a class of structural systems particularly prone to seismic actions. The controlled structureis a near full scale 2-story steel frame, equipped with two semi-active bracing systems including twomagnetorheological dampers designed and manufactured in Europe. A set of earthquake records has beenapplied at the base of the structure, by utilizing a shaking table facility. Experimental results are compared interms of displacements, absolute accelerations and energy dissipation capability. A further analysis on thepercentage incidence of undesired and/or unpredictable operations corresponding to each algorithm gives aninsight on some factors affecting the reliability and, in turn, the real effectiveness of semi-active structuralcontrol systems.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002018331
|
oai_dc
|
Online correction of drift in structural identification using artificial white noise observations and an unscented Kalman Filter
|
Online correction of drift in structural identification using artificial white noise observations and an unscented Kalman Filter
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Eleni N. Chatzi(ETH Zurich); Clemente Fuggini(D’Appolonia S.p.A.)"
] |
In recent years the monitoring of structural behavior through acquisition of vibrational data has become common practice. In addition, recent advances in sensor development have made the collection of diverse dynamic information feasible. Other than the commonly collected acceleration information, Global Position System (GPS) receivers and non-contact, optical techniques have also allowed for the synchronous collection of highly accurate displacement data. The fusion of this heterogeneous information is crucial for the successful monitoring and control of structural systems especially when aiming at real-time estimation.
This task is not a straightforward one as measurements are inevitably corrupted with some percentage of noise, often leading to imprecise estimation. Quite commonly, the presence of noise in acceleration signals results in drifting estimates of displacement states, as a result of numerical integration. In this study, a new approach based on a time domain identification method, namely the Unscented Kalman Filter (UKF), is proposed for correcting the “drift effect” in displacement or rotation estimates in an online manner, i.e., on the fly as data is attained. The method relies on the introduction of artificial white noise (WN) observations into the filter equations, which is shown to achieve an online correction of the drift issue, thus yielding highly accurate motion data. The proposed approach is demonstrated for two cases; firstly, the illustrative example of a single degree of freedom linear oscillator is examined, where availability of acceleration measurements is exclusively assumed. Secondly, a field inspired implementation is presented for the torsional identification of a tall tower structure, where acceleration measurements are obtained at a high sampling rate and non-collocated GPS displacement measurements are assumed available at a lower sampling rate. A multi-rate Kalman Filter is incorporated into the analysis in order to successfully fuse data sampled at different rates.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002018329
|
oai_dc
|
Vibration-based structural health monitoring of stay cables by microwave remote sensing
|
Vibration-based structural health monitoring of stay cables by microwave remote sensing
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Carmelo Gentile(Politecnico di Milano); Alessandro Cabboi(University of Cagliari)"
] |
Microwave remote sensing is probably the most recent experimental technique suitable to the non-contact measurement of deflections on large structures, in static or dynamic conditions. In the first part of the paper, the main techniques adopted in microwave remote sensing are described, so that advantages and potential issues of these techniques are presented and discussed. Subsequently, the paper addresses the application of the radar technology to the measurement of the vibration response on the stay cables of two cable-stayed bridges. The dynamic tests were performed in operational conditions (i.e. with the excitation being mainly provided by micro-tremors, wind and traffic) and the maximum deflections of the cables were generally lower than 5.0 mm. The investigation clearly highlights: (a) the safe and simple use of the radar on site and its effectiveness to simultaneously measure the dynamic response of all the stay cables of an array; (b) the negligible effects of the typical issues and uncertainties that might affect the radar measurements; (c) the accuracy of the results provided by the microwave remote sensing in terms of natural frequencies and tension forces of the stay cables; (d) the suitability of microwave interferometry to the repeated application within Structural Health Monitoring programmes.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002018330
|
oai_dc
|
An anti-noise real-time cross-correlation method for bolted joint monitoring using piezoceramic transducers
|
An anti-noise real-time cross-correlation method for bolted joint monitoring using piezoceramic transducers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jiabiao Ruan(University of Houston); Zhimin Zhang(University of Electronic Science and Technology of); Tao Wang(Wuhan University of Science and Technology); Yourong Li(Wuhan University of Science and Technology); Gangbing Song(University of Houston)"
] |
Bolted joint connection is the most commonly used connection element in structures and devices. The loosening due to external dynamic loads cannot be observed and measured easily and may cause catastrophic loss especially in an extreme requirement and/or environment. In this paper, an innovative Real-time Cross-Correlation Method (RCCM) for monitoring of the bolted joint loosening was proposed. We apply time reversal process on stress wave propagation to obtain correlation signal.
The correlation signal’s peak amplitude represents the cross-correlation between the loosening state and the baseline working state; therefore, it can detect the state of loosening. Since the bolt states are uncorrelated with noise, the peak amplitude will not be affected by noise and disturbance while it increases SNR level and increases the measured signals’ reliability. The correlation process is carried out online through physical wave propagation without any other post offline complicated analyses and calculations. We implemented the proposed RCCM on a single bolt/nut joint experimental device to quantitatively detect the loosening states successfully. After that we implemented the proposed method on a real large structure (reaction wall) with multiple bolted joint connections. Loosening indexes were built for both experiments to indicate the loosening states. Finally, we demonstrated the proposed method’s great anti-noise and/or disturbance ability. In the instrumentation, we simply mounted Lead Zirconium Titanate (PZT) patches on the device/structure surface without any modifications of the bolted connection. The low-cost PZTs used as actuators and sensors for active sensing are easily extended to a sensing network for large scale bolted joint network monitoring.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002018328
|
oai_dc
|
Optimal sensor placement under uncertainties using a nondirective movement glowworm swarm optimization algorithm
|
Optimal sensor placement under uncertainties using a nondirective movement glowworm swarm optimization algorithm
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Guang-Dong Zhou(Hohai University); Ting-Hua Yi(Dalian University of Technology); Huan Zhang(Dalian University of Technology); Huan Zhang(Dalian University of Technology); Hong-Nan Li(Hohai University)"
] |
Optimal sensor placement (OSP) is a critical issue in construction and implementation of a sophisticated structural health monitoring (SHM) system. The uncertainties in the identified structural parameters based on the measured data may dramatically reduce the reliability of the condition evaluation results. In this paper, the information entropy, which provides an uncertainty metric for the identified structural parameters, is adopted as the performance measure for a sensor configuration, and the OSP problem is formulated as the multi-objective optimization problem of extracting the Pareto optimal sensor configurations that simultaneously minimize the appropriately defined information entropy indices. The nondirective movement glowworm swarm optimization (NMGSO) algorithm (based on the basic glowworm swarm optimization (GSO) algorithm) is proposed for identifying the effective Pareto optimal sensor configurations. The one-dimensional binary coding system is introduced to code the glowworms instead of the real vector coding method. The Hamming distance is employed to describe the divergence of different glowworms. The luciferin level of the glowworm is defined as a function of the rank value (RV) and the crowding distance (CD), which are deduced by non-dominated sorting. In addition, nondirective movement is developed to relocate the glowworms. A numerical simulation of a long-span suspension bridge is performed to demonstrate the effectiveness of the NMGSO algorithm. The results indicate that the NMGSO algorithm is capable of capturing the Pareto optimal sensor configurations with high accuracy and efficiency.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002018334
|
oai_dc
|
Reliability-based assessment of steel bridge deck using a mesh-insensitive structural stress method
|
Reliability-based assessment of steel bridge deck using a mesh-insensitive structural stress method
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"X.W. Ye(Zhejiang University); Ting-Hua Yi(Dalian University of Technology); C. Wen(Lanzhou University of Technology); Y.H. Su(Lanzhou University of Technology)"
] |
This paper aims to conduct the reliability-based assessment of the welded joint in the orthotropic steel bridge deck by use of a mesh-insensitive structural stress (MISS) method, which is an effective numerical procedure to determine the reliable stress distribution adjacent to the weld toe. Both the solid element model and the shell element model are first established to investigate the sensitivity of the element size and the element type in calculating the structural stress under different loading scenarios. In order to achieve realistic condition assessment of the welded joint, the probabilistic approach based on the structural reliability theory is adopted to derive the reliability index and the failure probability by taking into account the uncertainties inherent in the material properties and load conditions. The limit state function is formulated in terms of the structural resistance of the material and the load effect which is described by the structural stress obtained by the MISS method. The reliability index is computed by use of the first-order reliability method (FORM), and compared with a target reliability index to facilitate the safety assessment.
The results achieved from this study reveal that the calculation of the structural stress using the MISS method is insensitive to the element size and the element type, and the obtained structural stress results serve as a reliable basis for structural reliability analysis.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002018333
|
oai_dc
|
Consistency of PPP GPS and strong-motion records: case study of Mw9.0 Tohoku-Oki 2011 earthquake
|
Consistency of PPP GPS and strong-motion records: case study of Mw9.0 Tohoku-Oki 2011 earthquake
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Panos Psimoulis(The University of Nottingham); Nicolas Houlié(Geodesy and Photogrammetry Institute); Michael Meindl(Institute of Geophysics); Markus Rothacher(Institute of Geophysics)"
] |
GPS and strong-motion sensors are broadly used for the monitoring of structural health and Earth surface motions, focusing on response of structures, earthquake characterization and rupture modeling. Several studies have shown the consistency of the two data sets within at certain frequency (e.g., 0.03<f<0.2Hz). The compatibility of Precise Point Positioning (PPP) GPS and strong-motion data was assessed by comparing their respective displacement waveforms for several frequency bands (f<0.4Hz). For this purpose, there are used GPS and strong-motion records of the Mw9.0 Tohoku 2011 earthquake at 23 very close spaced sites and conclude that the agreement between the two datasets depends on the frequency of the excitation, the direction of the excitation signal and the distance from the excitation source.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002018332
|
oai_dc
|
A new approach to deal with sensor errors in structural controls with MR damper
|
A new approach to deal with sensor errors in structural controls with MR damper
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Han Wang(University of Houston); Luyu Li(University of Houston); Gangbing Song(University of Houston); James B. Dabney(University of Houston); Thomas L. Harman(University of Houston)"
] |
As commonly known, sensor errors and faulty signals may potentially lead structures in vibration to catastrophic failures. This paper presents a new approach to deal with sensor errors/faults in vibration control of structures by using the Fault detection and isolation (FDI) technique. To demonstrate the effectiveness of the approach, a space truss structure with semi-active devices such as Magneto-Rheological (MR) damper is used as an example. To address the problem, a Linear Matrix Inequality (LMI) based fixed-order H∞ FDI filter is introduced and designed. Modeling errors are treated as uncertainties in the FDI filter design to verify the robustness of the proposed FDI filter. Furthermore, an innovative Fuzzy Fault Tolerant Controller (FFTC) has been developed for this space truss structure model to preserve the pre-specified performance in the presence of sensor errors or faults. Simulation results have demonstrated that the proposed FDI filter is capable of detecting and isolating sensor errors/faults and actuator faults e.g., accelerometers and MR dampers, and the proposed FFTC can maintain the structural vibration suppression in faulty conditions.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001998834
|
oai_dc
|
A comparative study for bending of cross-ply laminated plates resting on elastic foundations
|
A comparative study for bending of cross-ply laminated plates resting on elastic foundations
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ashraf M. Zenkour(King Abdulaziz University)"
] |
Two hyperbolic displacement models are used for the bending response of simply-supported orthotropic laminated composite plates resting on two-parameter elastic foundations under mechanical loading. The models contain hyperbolic expressions to account for the parabolic distributions of transverse shear stresses and to satisfy the zero shear-stress conditions at the top and bottom surfaces of the plates. The present theory takes into account not only the transverse shear strains, but also their parabolic variation across the plate thickness and requires no shear correction coefficients in computing the shear stresses. The governing equations are derived and their closed-form solutions are obtained. The accuracy of the models presented is demonstrated by comparing the results obtained with solutions of other theories models given in the literature. It is found that the theories proposed can predict the bending analysis of cross-ply laminated composite plates resting on elastic foundations rather accurately. The effects of Winkler and Pasternak foundation parameters, transverse shear deformations, plate aspect ratio, and side-to-thickness ratio on deflections and stresses are investigated.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001998819
|
oai_dc
|
Electromagnetothermoelastic behavior of a rotating imperfect hybrid functionally graded hollow cylinder
|
Electromagnetothermoelastic behavior of a rotating imperfect hybrid functionally graded hollow cylinder
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Saadatfar(K.N. Toosi University of Technology); M. Aghaie-Khafri(K.N. Toosi University of Technology)"
] |
The electro-magneto- thermo-elastic behavior of a rotating functionally graded long hollow cylinder with functionally graded piezoelectric (FGPM) layers is analytically analyzed. The layers are imperfectly bonded to its inner and outer surfaces. The hybrid cylinder is placed in a constant magnetic field subjected to a thermo-electro-mechanical loading and could be rested on a Winkler-type elastic foundation.
The material properties of the FGM cylinder and radially polarized FGPM layers are assumed to be graded in the radial direction according to the power law. The hybrid cylinder is rotating about its axis at a constant angular velocity. The governing equations are solved analytically and then stresses, displacement and electric potential distribution are calculated. Numerical examples are given to illustrate the effects of material in-homogeneity, magnetic field, elastic foundation, applied voltage, imperfect interface and thermo-mechanical boundary condition on the static behavior of a FG smart cylinder.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001998832
|
oai_dc
|
Experimental analyses of dynamical systems involving shape memory alloys
|
Experimental analyses of dynamical systems involving shape memory alloys
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Søren Enemark(Technical University of Denmark); Marcelo A. Savi(Universidade Federal do Rio de Janeiro); Ilmar F. Santos(Technical University of Denmark)"
] |
The use of shape memory alloys (SMAs) in dynamical systems has an increasing importance in engineering especially due to their capacity to provide vibration reductions. In this regard, experimental tests are essential in order to show all potentialities of this kind of systems. In this work, SMA springs are incorporated in a dynamical system that consists of a one degree of freedom oscillator connected to a linear spring and a mass, which is also connected to the SMA spring. Two types of springs are investigated defining two distinct systems: a pseudoelastic and a shape memory system. The characterisation of the springs is evaluated by considering differential calorimetry scanning tests and also force-displacement tests at different temperatures. Free and forced vibration experiments are made in order to investigate the dynamical behaviour of the systems. For both systems, it is observed the capability of changing the equilibrium position due to phase transformations leading to hysteretic behaviour, or due to temperature changes which also induce phase transformations and therefore, change in stiffness. Both situations are investigated by promoting temperature changes and also pre-tension of the springs. This article shows several experimental tests that allow one to obtain a general comprehension of the dynamical behaviour of SMA systems. Results show the general thermo-mechanical behaviour of SMA dynamical systems and the obtained conclusions can be applied in distinct situations as in rotor-bearing systems.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001998837
|
oai_dc
|
Self-reliant wireless health monitoring based on tuned-mass-damper mechanism
|
Self-reliant wireless health monitoring based on tuned-mass-damper mechanism
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kanjuro Makihara(Tohoku University); Hidekazu Hirai(Shinko Electric Industries Co., Ltd.); Yuta Yamamoto(Tohoku University); Hisao Fukunaga(Tohoku University)"
] |
We propose an electrically self-reliant structural health monitoring (SHM) system that is able to wirelessly transmit sensing data using electrical power generated by vibration without the need for additional external power sources. The provision of reliable electricity to wireless SHM systems is a highly important issue that has often been ignored, and to expand the applicability of various wireless SHM innovations, it will be necessary to develop comprehensive wireless SHM devices including stable electricity sources. In light of this need, we propose a new, highly efficient vibration-powered generator based on a tuned-mass-damper (TMD) mechanism that is quite suitable for vibration-based SHM. The charging time of the TMD generator is shorter than that of conventional generators based on the impedance matching method, and the proposed TMD generator can harvest 16 times the amount of energy that a conventional generator can. The charging time of an SHM wireless transmitter is quantitatively formulated. We conduct wireless monitoring experiments to validate a wireless SHM system composed of a self-reliant SHM and a vibration-powered TMD generator.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001998835
|
oai_dc
|
Smart monitoring system with multi-criteria decision using a feature based computer vision technique
|
Smart monitoring system with multi-criteria decision using a feature based computer vision technique
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chih-Wei Lin(National Taiwan University); Wen-Ko Hsu(National Central University); Dung-Jiang Chiou(National Central University); Cheng-Wu Chen(National Kaohsiung Marine University); Wei-Ling Chiang(National Central University)"
] |
When natural disasters occur, including earthquakes, tsunamis, and debris flows, they are often accompanied by various types of damages such as the collapse of buildings, broken bridges and roads, and the destruction of natural scenery. Natural disaster detection and warning is an important issue which could help to reduce the incidence of serious damage to life and property as well as provide information for search and rescue afterwards. In this study, we propose a novel computer vision technique for debris flow detection which is feature-based that can be used to construct a debris flow event warning system. The landscape is composed of various elements, including trees, rocks, and buildings which are characterized by their features, shapes, positions, and colors. Unlike the traditional methods, our analysis relies on changes in the natural scenery which influence changes to the features. The “background module” and “monitoring module” procedures are designed and used to detect debris flows and construct an event warning system. The multi-criteria decision-making method used to construct an event warring system includes gradient information and the percentage of variation of the features. To prove the feasibility of the proposed method for detecting debris flows, some real cases of debris flows are analyzed. The natural environment is simulated and an event warning system is constructed to warn of debris flows. Debris flows are successfully detected using these two procedures, by analyzing the variation in the detected features and the matched feature. The feasibility of the event warning system is proven using the simulation method. Therefore, the feature based method is found to be useful for detecting debris flows and the event warning system is triggered when debris flows occur.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001998814
|
oai_dc
|
Hinge rotation of a morphing rib using FBG strain sensors
|
Hinge rotation of a morphing rib using FBG strain sensors
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Monica Ciminello(C.I.R.A.- Italian Aerospace Research Center); Salvatore Ameduri(C.I.R.A.- Italian Aerospace Research Center); Antonio Concilio(C.I.R.A.- Italian Aerospace Research Center); Domenico Flauto(University of Palermo); Fabio Mennella(University of Napoli)"
] |
An original sensor system based on Fiber Bragg Gratings (FBG) for the strain monitoring of an adaptive wing element is presented in this paper. One of the main aims of the SARISTU project is in fact to measure the shape of a deformable wing for performance optimization. In detail, an Adaptive Trailing Edge (ATE) is monitored chord- and span-wise in order to estimate the deviation between the actual and the desired shape and, then, to allow attaining a prediction of the real aerodynamic behavior with respect to the expected one. The integration of a sensor system is not trivial: it has to fit inside the available room and to comply with the primary issue of the FBG protection. Moreover, dealing with morphing structures, large deformations are expected and a certain modulation is necessary to keep the measured strain inside the permissible measure range. In what follows, the mathematical model of an original FBG-based structural sensor system is presented, designed to evaluate the chord-wise strain of an Adaptive Trailing Edge device.
Numerical and experimental results are compared, using a proof-of-concept setup. Further investigations aimed at improving the sensor capabilities, were finally addressed. The elasticity of the sensor structure was exploited to enlarge both the measurement and the linearity range. An optimisation process was then implemented to find out an optimal thickness distribution of the sensor system in order to alleviate the strain level within the referred component.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001998824
|
oai_dc
|
Seismic responses of base-isolated buildings: efficacy of equivalent linear modeling under near-fault earthquakes
|
Seismic responses of base-isolated buildings: efficacy of equivalent linear modeling under near-fault earthquakes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Cenk Alhan(Istanbul University); Murat Özgür(Istanbul University)"
] |
Design criteria, modeling rules, and analysis principles of seismic isolation systems have already found place in important building codes and standards such as the Uniform Building Code and ASCE/SEI 7-05. Although real behaviors of isolation systems composed of high damping or lead rubber bearings are nonlinear, equivalent linear models can be obtained using effective stiffness and damping which makes use of linear seismic analysis methods for seismic-isolated buildings possible. However, equivalent linear modeling and analysis may lead to errors in seismic response terms of multi-story buildings and thus need to be assessed comprehensively. This study investigates the accuracy of equivalent linear modeling via numerical experiments conducted on generic five-story three dimensional seismic-isolated buildings. A wide range of nonlinear isolation systems with different characteristics and their equivalent linear counterparts are subjected to historical earthquakes and isolation system displacements, top floor accelerations, story drifts, base shears, and torsional base moments are compared. Relations between the accuracy of the estimates of peak structural responses from equivalent linear models and typical characteristics of nonlinear isolation systems including effective period, rigid-body mode period, effective viscous damping ratio, and post-yield to pre-yield stiffness ratio are established. Influence of biaxial interaction and plan eccentricity are also examined.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001998826
|
oai_dc
|
On time reversal-based signal enhancement for active lamb wave-based damage identification
|
On time reversal-based signal enhancement for active lamb wave-based damage identification
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Qiang Wang(Nanjing University of Posts and Telecommunications); Shenfang Yuan(Nanjing University of Aeronautics and Astronautics); Ming Hong(The Hong Kong Polytechnic University); Zhongqing Su(The Hong Kong Polytechnic University Shenzhen Res)"
] |
Lamb waves have been a promising candidate for quantitative damage identification for various engineering structures, taking advantage of their superb capabilities of traveling for long distances with fast propagation and low attenuation. However, the application of Lamb waves in damage identification so far has been hampered by the fact that the characteristic signals associated with defects are generally weaker compared with those arising from boundary reflections, mode conversions and environmental noises, making it a tough task to achieve satisfactory damage identification from the time series. With awareness of this challenge, this paper proposes a time reversal-based technique to enhance the strength of damage-scattered signals, which has been previously applied to bulk wave-based damage detection successfully. The investigation includes (i) an analysis of Lamb wave propagation in a plate, generated by PZT patches mounted on the structure; (ii) an introduction of the time reversal theory dedicated for waveform reconstruction with a narrow-band input; (iii) a process of enhancing damage-scattered signals based on time reversal focalization; and (iv) the experimental investigation of the proposed approach to enhance the damage identification on a composite plate. The results have demonstrated that signals scattered by delamination in the composite plate can be enhanced remarkably with the assistance of the proposed process, benefiting from which the damage in the plate is identified with ease and high precision.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001998836
|
oai_dc
|
Nonlinear large deformation dynamic analysis of electroactive polymer actuators
|
Nonlinear large deformation dynamic analysis of electroactive polymer actuators
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Amir Ali Amiri Moghadam(Deakin University); Abbas Kouzani(Deakin University); Reza Zamani(University of Wollongong); Kevin Magniez(Deakin University); Akif Kaynak(Deakin University)"
] |
Electroactive polymers have attracted considerable attention in recent years due to their sensing and actuating properties which make them a material of choice for a wide range of applications including sensors, biomimetic robots, and biomedical micro devices. This paper presents an effective modeling strategy for nonlinear large deformation (small strains and moderate rotations) dynamic analysis of polymer actuators. Considering that the complicated electro-chemo-mechanical dynamics of these actuators is a drawback for their application in functional devices, establishing a mathematical model which can effectively predict the actuator’s dynamic behavior can be of paramount importance. To effectively predict the actuator’s dynamic behavior, a comprehensive mathematical model is proposed correlating the input voltage and the output bending displacement of polymer actuators. The proposed model, which is based on the rigid finite element (RFE) method, consists of two parts, namely electrical and mechanical models. The former is comprised of a ladder network of discrete resistive-capacitive components similar to the network used to model transmission lines, while the latter describes the actuator as a system of rigid links connected by spring-damping elements (sdes). Both electrical and mechanical components are validated through experimental results.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001998829
|
oai_dc
|
A novel solution for thick-walled cylinders made of functionally graded materials
|
A novel solution for thick-walled cylinders made of functionally graded materials
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y.Z. Chen(Jiangsu University)"
] |
This paper provides a novel solution for thick-walled cylinders made of functionally graded materials (FGMs). In the formulation, the cylinder is divided into N layers. On the individual layer, the Young’s modulus is assumed to be a constant. For an individual layer, two undetermined constants are involved in the elastic solution. Those undetermined coefficients can be evaluated from the continuation condition along interfaces of layers and the boundary conditions at the inner surface and outer surface of cylinder. Finally, the solution for thick-walled cylinders made of functionally graded materials is obtainable.
This paper provides several numerical examples which are useful for engineer to design a cylinder made of FGMs.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001998828
|
oai_dc
|
Experimental study of controllable MR-TLCD applied to the mitigation of structure vibration
|
Experimental study of controllable MR-TLCD applied to the mitigation of structure vibration
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chih-Wen Cheng(National Sun Yat-sen University); Hsien Hua Lee(National Sun Yat-sen University); Yuan-Tzuo Luo(National Sun Yat-sen University)"
] |
MR-TLCD (Magneto-Rheological Tuned Liquid Column Damper) is a new developed vibration control device, which combines the traditional passive control property with active controllability advantage.
Based on traditional TLCD governing equation, this study further considers MR-fluid viscosity in the equation and by transforming the non-linear damping term into an equivalent linear damping, a solution can be obtained. In order to find a countable set of parameters for the design of the MR-TLCD system and also to realize its applicability to structures, a series of experimental test were designed and carried out. The testing programs include the basic material properties of the MR-fluid, the damping ratio of a MR-TLCD and the dynamic responses for a frame structure equipped with the MR-TLCD system subjected to strong ground excitations. In both the analytical and experimental results of this study, it is found that the accurately tuned MR-TLCD system could effectively reduce the dynamic response of a structural system.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001998833
|
oai_dc
|
Design and calibration of a wireless laser-based optical sensor for crack propagation monitoring
|
Design and calibration of a wireless laser-based optical sensor for crack propagation monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S.H. Man(Hong Kong University); C.C. Chang(Hong Kong University); M. Hassan(Hong Kong University); A. Bermak(Hong Kong University)"
] |
In this study, a wireless crack sensor is developed for monitoring cracks propagating in two dimensions. This sensor is developed by incorporating a laser-based optical navigation sensor board (ADNS-9500) into a smart wireless platform (Imote2). To measure crack propagation, the Imote2 sends a signal to the ADNS-9500 to collect a sequence of images reflected from the concrete surface. These acquired images can be processed in the ADNS-9500 directly (the navigation mode) or sent to Imote2 for processing (the frame capture mode). The computed crack displacement can then be transmitted wirelessly to a base station. The design and the construction of this sensor are reported herein followed by some calibration tests on one prototype sensor. Test results show that the sensor can provide sub-millimeter accuracy under sinusoidal and step movement. Also, the two modes of operation offer complementary performance as the navigation mode is more accurate in tracking large amplitude and fast crack movement while the frame capture mode is more accurate for small and slow crack movement. These results illustrate the feasibility of developing such a crack sensor as well as point out directions of further research before its actual implementation.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001991440
|
oai_dc
|
The effect of different functionalities of FGM and FGPM layers on free vibration analysis of the FG circular plates integrated with piezoelectric layers
|
The effect of different functionalities of FGM and FGPM layers on free vibration analysis of the FG circular plates integrated with piezoelectric layers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Arefi(University of Kashan)"
] |
The present paper deals with the free vibration analysis of the functionally graded solid and annular circular plates with two functionally graded piezoelectric layers at top and bottom subjected to an electric field. Classical plate theory (CPT) is used for description of the all deformation components based on a symmetric distribution. All the mechanical and electrical properties except Poisson’s ratio can vary continuously along the thickness direction of the plate. The properties of plate core can vary from metal at bottom to ceramic at top. The effect of non homogeneous index of functionally graded and functionally graded piezoelectric sections can be considered on the results of the system. 1st and 2nd modes of natural frequencies of the system have been evaluated for both solid and annular circular plates, individually.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001991442
|
oai_dc
|
Health monitoring sensor placement optimization for Canton Tower using virus monkey algorithm
|
Health monitoring sensor placement optimization for Canton Tower using virus monkey algorithm
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ting-Hua Yi(Dalian University of Technology); Hong-Nan Li(Dalian University of Technology); Xu-Dong Zhang(Dalian University of Technology)"
] |
Placing sensors at appropriate locations is an important task in the design of an efficient structural health monitoring (SHM) system for a large-scale civil structure. In this paper, a hybrid optimization algorithm called virus monkey algorithm (VMA) based on the virus theory of evolution is proposed to seek the optimal placement of sensors. Firstly, the dual-structure coding method is adopted instead of binary coding method to code the solution. Then, the VMA is designed to incorporate two populations, a monkey population and a virus population, enabling the horizontal propagation between the monkey and virus individuals and the vertical inheritance of monkey’s position information from the previous to following position. Correspondingly, the monkey population in this paper is divided into the superior and inferior monkey populations, and the virus population is divided into the serious and slight virus populations. The serious virus is used to infect the inferior monkey to make it escape from the local optima, while the slight virus is adopted to infect the superior monkey to let it find a better result in the nearby area. This kind of novel virus infection operator enables the coevolution of monkey and virus populations. Finally, the effectiveness of the proposed VMA is demonstrated by designing the sensor network of the Canton Tower, the tallest TV Tower in China. Results show that innovations in the VMA proposed in this paper can improve the convergence of algorithm compared with the original monkey algorithm (MA).
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001991438
|
oai_dc
|
Mathematical solution for nonlinear vibration equations using variational approach
|
Mathematical solution for nonlinear vibration equations using variational approach
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Bayat(Islamic Azad University); I. Pakar(Islamic Azad University)"
] |
In this paper, we have applied a new class of approximate analytical methods called Variational Approach (VA) for high nonlinear vibration equations. Three examples have been introduced and discussed.
The effects of important parameters on the response of the problems have been considered. Runge-Kutta’s algorithm has been used to prepare numerical solutions. The results of variational approach are compared with energy balance method and numerical and exact solutions. It has been established that the method is an easy mathematical tool for solving conservative nonlinear problems. The method doesn’t need small perturbation and with only one iteration achieve us to a high accurate solution.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001991431
|
oai_dc
|
Optimal control and design of composite laminated piezoelectric plates
|
Optimal control and design of composite laminated piezoelectric plates
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"ALhadi E. ALamir(Najran university)"
] |
The present paper is concerned with the optimal control and/or design of symmetric and antisymmetric composite laminate with two piezoelectric layers bonded to the opposite surfaces of the laminate, and placed symmetrically with respect to the middle plane. For the optimal control problem, Liapunov-Bellman theory is used to minimize the dynamic response of the laminate. The dynamic response of the laminate comprises a weight sum of the control objective (the total vibrational energy) and a penalty functional including the control force. Simultaneously with the active control, thicknesses and the orientation angles of layers are taken as design variables to achieve optimum design. The formulation is based on various plate theories for various boundary conditions. Explicit solutions for the control function and controlled deflections are obtained in forms of double series. Numerical results are given to demonstrate the effectiveness of the proposed control and design mechanism, and to investigate the effects of various laminate parameters on the control and design process.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001991432
|
oai_dc
|
Force identification by using specific forms of PVDF patches
|
Force identification by using specific forms of PVDF patches
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Simon Chesné(Lyon University); Charles Pézerat(Maine University)"
] |
This paper deals with the experimental validation of the use of PVDF Patches for the assessment of spatial derivatives of displacement field. It focuses more exactly on the shear Force Identification by using Specific forms of PVDF patcHes (FISH) on beams. An overview of the theoretical approach is exposed. The principle is based on the use of the weak form of the equation of motion of the beam which allows the shear forces to be extracted at one edge of the sensor when this last has a specific form. The experimental validation is carried out with a cantilever steel beam, excited by a shaker at its free boundary.
The validation consists in comparing the shear force measured by the designed sensor glued at the free edge and the directly measured force applied by the shaker. The sensor is made of two patches, called the "stiffness" patch and the "mass" patch. The use of both patches allows one to identify correctly the shear force on a large frequency domain. The use of only the stiffness patch is valid in the low frequency domain and has the advantage to have a frequency-independent gain that allows its use in real time.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001991437
|
oai_dc
|
Seismic analysis of 3-D two adjacent buildings connected by viscous dampers with effect of underneath different soil kinds
|
Seismic analysis of 3-D two adjacent buildings connected by viscous dampers with effect of underneath different soil kinds
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ahmed Abdelraheem Farghaly(Sohag University)"
] |
3D two adjacent buildings with different heights founded in different kinds of soil connected with viscous dampers groups, with especial arrangement in plane, were investigated. Soil structure interaction for three different kinds of soil (stiff, medium and soft) were modeled as 3D Winkler model to give the realistic behavior of adjacent buildings connected with viscous dampers under various earthquake excitations taking in the account the effect of different kinds of soil beneath the buildings, using SAP2000n to model the whole system. A range of soil properties and soil damping characteristics are chosen which gives broad picture of connected structures system behavior resulted from the influence soil-structure interaction. Its conclusion that the response of connected structures system founded on soft soil are more critical than those founded on stiff soil. The behavior of connected structures is different from those with fixed base bigger by nearly 20%, and the efficiency of viscous dampers connecting the two adjacent buildings is reduced by nearly 25% less than those founded on stiff soil.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001991441
|
oai_dc
|
A methodology for sustainable monitoring of micro locations at remote, hard-to-access and unsafe places
|
A methodology for sustainable monitoring of micro locations at remote, hard-to-access and unsafe places
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Tamara Trček-Pečak(University of Ljubljana); Denis Trček(University of Ljubljana); Igor Belič(Institute of Metals and Technology, Lepi pot 11)"
] |
Smart structures and intelligent systems play pivotal roles in numerous areas of applied sciences ranging from civil engineering to computer and communications systems engineering. Although such structures and systems have been intensively deployed in these areas, they have been, interestingly, very rarely deployed in the field of cultural heritage preservation.This paper presents one of thefirst such attempts.
A new methodology is describedthat deploys smart structures andlinks them with artificial intelligence methods.These solutions are referred toas advanced hybrid engineering artefacts. By their use,important environmental factors can be monitoredin hard to access, remote or unsafe locationsby minimizing the need for human involvement. In addition toproviding safety the methodologyalso reduces costs and, most importantly,providesa new way to modelany particular micro-environment in a much more efficient way than this is possible with traditional ways. Last but not least, although themethodology has been developed for cultural heritage preservation, its application areas are much broader and it is expected that it will find its applicationin other domains like civil engineering and ecology.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001991433
|
oai_dc
|
Damage detection of multi-storeyed shear structure using sparse and noisy modal data
|
Damage detection of multi-storeyed shear structure using sparse and noisy modal data
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S.K. Panigrahi(CSIR-Central Building Research Institute); S. Chakraverty(NIT); S.K. Bhattacharyya(CSIR-Central Building Research Institute)"
] |
In the present paper, a method for identifying damage in a multi storeyed shear building structure is presented using minimum number of modal parameters of the structure. A damage at any level of the structure may lead to a major failure if the damage is not attended at appropriate time. Hence an early detection of damage is essential. The proposed identification methodology requires experimentally determined sparse modal data of any particular mode as input to detect the location and extent of damage in the structure. Here, the first natural frequency and corresponding partial mode shape values are used as input to the model and results are compared by changing the sensor placement locations at different floors to conclude the best location of sensors for accurate damage identification. Initially experimental data are simulated numerically by solving eigen value problem of the damaged structure with inclusion of random noise on the vibration characteristics. Reliability of the procedure has been demonstrated through a few examples of multi storeyed shear structure with different damage scenarios and various noise levels.
Validation of the methodology has also been done using dynamic data obtained through experiment conducted on a laboratory scale steel structure.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001991436
|
oai_dc
|
Theoretical analysis of superelastic SMA helical structures subjected to axial and torsional loads
|
Theoretical analysis of superelastic SMA helical structures subjected to axial and torsional loads
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xiang Zhou(Shanghai Jiao Tong University); Zhong You(University of Oxford)"
] |
Helical structures made of superelastic shape memory alloys are widely used as interventional medical devices and active actuators. These structures generally undergo large deformation during expansion or actuation. Currently their behaviour is modelled numerically using the finite element method or obtained through experiments. Analytical tools are absent. In this paper, an analytical approach has been developed for analyzing the mechanical responses of such structures subjected to axial and torsional loads.
The simulation results given by the analytical approach have been compared with both numerical and experimental data. Good agreements between the results indicate that the analysis is valid.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001991439
|
oai_dc
|
Repetitive model refinement for structural health monitoring using efficient Akaike information criterion
|
Repetitive model refinement for structural health monitoring using efficient Akaike information criterion
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jeng-Wen Lin(Feng Chia University)"
] |
The stiffness of a structure is one of several structural signals that are useful indicators of the amount of damage that has been done to the structure. To accurately estimate the stiffness, an equation of motion containing a stiffness parameter must first be established by expansion as a linear series model, a Taylor series model, or a power series model. The model is then used in multivariate autoregressive modeling to estimate the structural stiffness and compare it to the theoretical value. Stiffness assessment for modeling purposes typically involves the use of one of three statistical model refinement approaches, one of which is the efficient Akaike information criterion (AIC) proposed in this paper. If a newly added component of the model results in a decrease in the AIC value, compared to the value obtained with the previously added component(s), it is statistically justifiable to retain this new component; otherwise, it should be removed. This model refinement process is repeated until all of the components of the model are shown to be statistically justifiable. In this study, this model refinement approach was compared with the two other commonly used refinement approaches: principal component analysis (PCA) and principal component regression (PCR) combined with the AIC. The results indicate that the proposed AIC approach produces more accurate structural stiffness estimates than the other two approaches.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001991435
|
oai_dc
|
Damage detection based on MCSS and PSO using modal data
|
Damage detection based on MCSS and PSO using modal data
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ali Kaveh(Iran University of Science and Technology); Mohsen Maniat (Iran University of Science and Technology)"
] |
In this paper Magnetic Charged System Search (MCSS) and Particle Swarm Optimization (PSO) are applied to the problem of damage detection using frequencies and mode shapes of the structures. The objective is to identify the location and extent of multi-damage in structures. Both natural frequencies and mode shapes are used to form the required objective function. To moderate the effect of noise on measured data, a penalty approach is applied. A variety of numerical examples including two beams and two trusses are considered. A comparison between the PSO and MCSS is conducted to show the efficiency of the MCSS in finding the global optimum. The results show that the present methodology can reliably identify damage scenarios using noisy measurements and incomplete data.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001991434
|
oai_dc
|
Crack identification in post-buckled beam-type structures
|
Crack identification in post-buckled beam-type structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Shapour Moradi(Shahid Chamran University); Peyman Jamshidi Moghadam(Shahid Chamran University)"
] |
This study investigates the problem of crack detection in post-buckled beam-type structures.
The beam under the axial compressive force has a crack, assumed to be open and through the width. The crack, which is modeled by a massless rotational spring, divides the beam into two segments. The crack detection is considered as an optimization problem, and the weighted sum of the squared errors between the measured and computed natural frequencies is minimized by the bees algorithm. To find the natural frequencies, the governing nonlinear equations of motion for the post-buckled state are first derived. The solution of the nonlinear differential equations of the two segments consists of static and dynamic parts. The differential quadrature method along with an arc length strategy is used to solve the static part, while the same method is utilized for the solution of the linearized dynamic part and the extraction of the natural frequencies of the cracked beam. The investigation includes several numerical as well as experimental case studies on the post-buckled simply supported and clamped-clamped beams having open cracks. The results show that several parameters such as the amount of applied compressive force and boundary conditions influences the outcome of the crack detection scheme. The identification results also show that the crack position and depth can be predicted well by the presented method.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002013493
|
oai_dc
|
Nonlinear electromechanical analysis of a functionally graded square plate integrated with smart layers resting on Winkler-Pasternak foundation
|
Nonlinear electromechanical analysis of a functionally graded square plate integrated with smart layers resting on Winkler-Pasternak foundation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mohammad Arefi(University of Kashan)"
] |
This paper presents nonlinear analysis of a functionally graded square plate integrated with two functionally graded piezoelectric layers resting on the Winkler-Pasternak foundation. Geometric nonlinearity was considered in the strain-displacement relation based on the Von-Karman assumption. All the mechanical and electrical properties except Poisson\'s ratio can vary continuously along the thickness of the plate based on a power function. Electric potential was assumed as a quadratic function along the thickness direction and trigonometric function along the planar coordinate. The effect of non homogeneous index was investigated on the responses of the system. Furthermore, a comprehensive investigation has been performed for studying the effect of two parameters of assumed foundation on the mechanical and electrical components. A comparison between linear and nonlinear responses of the system presents necessity of this study.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002013490
|
oai_dc
|
Stochastic micro-vibration response characteristics of a sandwich plate with MR visco-elastomer core and mass
|
Stochastic micro-vibration response characteristics of a sandwich plate with MR visco-elastomer core and mass
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Z. G. Ying(Zhejiang University); Y. Q. Ni(The Hong Kong Polytechnic University); Y.F. Duan(Zhejiang University)"
] |
The magneto-rheological visco-elastomer (MRVE) is used as a smart core to control the stochastic micro-vibration of a sandwich plate with supported mass. The micro-vibration response of the sandwich plate with MRVE core and supported mass under stochastic support motion excitations is studied and compared to evaluate the vibration suppression capability. The effects of the supported mass and localized magnetic field on the stochastic micro-vibration response of the MRVE sandwich plate are taken into account. The dynamic characteristics of the MRVE core in micro-vibration are described by a non-homogeneous complex modulus dependent on vibration frequency and controllable by applied magnetic fields. The partial differential equations for the coupled transverse and longitudinal motions of the MRVE sandwich plate with supported mass are derived from the dynamic equilibrium, constitutive and geometric relations. The simplified ordinary differential equations are obtained for the transverse vibration of the MRVE sandwich plate under localized magnetic fields. A frequency-domain solution method for the stochastic micro-vibration response of sandwich plates with supported mass is developed based on the Galerkin method and random vibration theory. The expressions of frequency-response functions, response power spectral densities and root-mean-square velocity responses of the plate in terms of the one-third octave frequency band are obtained for micro-vibration evaluation. Finally, numerical results are given to illustrate the large response reduction capacity of the MRVE sandwich plate with supported mass under stochastic support motion excitations, and the influences of MRVE parameters, supported mass and localized magnetic field placement on the micro-vibration response.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002013487
|
oai_dc
|
Experimental study on acoustic emission characteristics of reinforced concrete components
|
Experimental study on acoustic emission characteristics of reinforced concrete components
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Aijun Gu(Jiangsu University); Ying Luo(Jiangsu University); Baiqiang X(Jiangsu University)"
] |
Acoustic emission analysis is an effective technique for monitoring the evolution of damage in a structure. An experimental analysis on a set of reinforced concrete beams under flexural loading was carried out. A mixed AE analysis method which used both parameter-based and signal-based techniques was presented to characterize and identify different failure mechanisms of damage, where the signal-based analysis was performed by using the Hilbert-Huang transform. The maximum instantaneous energy of typical damage events and the corresponding frequency characteristics were established, which provided a quantitative assessment of reinforced concrete beam using AE technique. In the bending tests, a \"pitch-catch\" system was mounted on a steel bar to assess bonding state of the steel bar in concrete. To better understand the AE behavior of bond-slip damage between steel bar and concrete, a special bond-slip test called pullout test was also performed. The results provided the basis of quantitative AE to identify both failure mechanisms and level of damages of civil engineering structures.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002013486
|
oai_dc
|
A multi-resolution analysis based finite element model updating method for damage identification
|
A multi-resolution analysis based finite element model updating method for damage identification
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xin Zhang(Zhengzhou University); Danying Gao(Zhengzhou University); Yang Liu(Zhengzhou University)"
] |
A novel finite element (FE) model updating method based on multi-resolution analysis (MRA) is proposed. The true stiffness of the FE model is considered as the superposition of two pieces of stiffness information of different resolutions: the pre-defined stiffness information and updating stiffness information. While the resolution of former is solely decided by the meshing density of the FE model, the resolution of latter is decided by the limited information obtained from the experiment. The latter resolution is considerably lower than the former. Second generation wavelet is adopted to describe the updating stiffness information in the framework of MRA. This updating stiffness in MRA is realized at low level of resolution, therefore, needs less number of updating parameters. The efficiency of the optimization process is thus enhanced. The proposed method is suitable for the identification of multiple irregular cracks and performs well in capturing the global features of the structural damage. After the global features are identified, a refinement process proposed in the paper can be carried out to improve the performance of the MRA of the updating information. The effectiveness of the method is verified by numerical simulations of a box girder and the experiment of a three-span continues pre-stressed concrete bridge. It is shown that the proposed method corresponds well to the global features of the structural damage and is stable against the perturbation of modal parameters and small variations of the damage.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002013495
|
oai_dc
|
Damage detection on a full-scale highway sign structure with a distributed wireless sensor network
|
Damage detection on a full-scale highway sign structure with a distributed wireless sensor network
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zhuoxiong Sun(Purdue University); Sriram Krishnan(Purdue University); Greg Hackmann(Washington University); Guirong Yan(University of Texas at El Paso); Shirley J. Dyke(Purdue University); Chenyang Lu(Washington University); Ayhan Irfanoglu(Purdue University)"
] |
Wireless sensor networks (WSNs) have emerged as a novel solution to many of the challenges of structural health monitoring (SHM) in civil engineering structures. While research projects using WSNs are ongoing worldwide, implementations of WSNs on full-scale structures are limited. In this study, a WSN is deployed on a full-scale 17.3m-long, 11-bay highway sign support structure to investigate the ability to use vibration response data to detect damage induced in the structure. A multi-level damage detection strategy is employed for this structure: the Angle-between-String-and-Horizon (ASH) flexibility-based algorithm as the Level I and the Axial Strain (AS) flexibility-based algorithm as the Level II. For the proposed multi-level damage detection strategy, a coarse resolution Level I damage detection will be conducted first to detect the damaged region(s). Subsequently, a fine resolution Level II damage detection will be conducted in the damaged region(s) to locate the damaged element(s). Several damage cases are created on the full-scale highway sign support structure to validate the multi-level detection strategy. The multi-level damage detection strategy is shown to be successful in detecting damage in the structure in these cases.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002013488
|
oai_dc
|
Nonlinear responses of an arbitrary FGP circular plate resting on the Winkler-Pasternak foundation
|
Nonlinear responses of an arbitrary FGP circular plate resting on the Winkler-Pasternak foundation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mohammad Arefi(University of Kashan); M.N.M. Allam(Mansoura University)"
] |
This paper presents nonlinear analysis of an arbitrary functionally graded circular plate integrated with two functionally graded piezoelectric layers resting on the Winkler-Pasternak foundation. Geometric nonlinearity is considered in the strain-displacement relation based on the Von-Karman assumption. All the mechanical and electrical properties except Poisson\'s ratio can vary continuously along the thickness of the plate based on a power function. Electric potential is assumed as a quadratic function along the thickness direction. After derivation of general nonlinear equations, as an instance, numerical results of a functionally graded material integrated with functionally graded piezoelectric material obeying two different functionalities is investigated. The effect of different parameters such as parameters of foundation, non homogenous index and boundary conditions can be investigated on the mechanical and electrical results of the system. A comprehensive comparison between linear and nonlinear responses of the system presents necessity of this study. Furthermore, the obtained results can be validated by using previous linear and nonlinear analyses after removing the effect of foundation.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002013491
|
oai_dc
|
Overall damage identification of flag-shaped hysteresis systems under seismic excitation
|
Overall damage identification of flag-shaped hysteresis systems under seismic excitation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Cong Zhou(University of Canterbury); J. Geoffrey Chase(University of Canterbury); Geoffrey W. Rodgers(University of Canterbury); Hamish Tomlinson(University of Canterbury); Chao Xu(Northwestern Polytechnical University)"
] |
This research investigates the structural health monitoring of nonlinear structures after a major seismic event. It considers the identification of flag-shaped or pinched hysteresis behavior in response to structures as a more general case of a normal hysteresis curve without pinching. The method is based on the overall least squares methods and the log likelihood ratio test. In particular, the structural response is divided into different loading and unloading sub-half cycles. The overall least squares analysis is first implemented to obtain the minimum residual mean square estimates of structural parameters for each sub-half cycle with the number of segments assumed. The log likelihood ratio test is used to assess the likelihood of these nonlinear segments being true representations in the presence of noise and model error. The resulting regression coefficients for identified segmented regression models are finally used to obtain stiffness, yielding deformation and energy dissipation parameters. The performance of the method is illustrated using a single degree of freedom system and a suite of 20 earthquake records. RMS noise of 5%, 10%, 15% and 20% is added to the response data to assess the robustness of the identification routine. The proposed method is computationally efficient and accurate in identifying the damage parameters within 10% average of the known values even with 20% added noise. The method requires no user input and could thus be automated and performed in real-time for each sub-half cycle, with results available effectively immediately after an event as well as during an event, if required.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002013494
|
oai_dc
|
An improved cross-correlation method based on wavelet transform and energy feature extraction for pipeline leak detection
|
An improved cross-correlation method based on wavelet transform and energy feature extraction for pipeline leak detection
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Suzhen Li(Tongji University); Xinxin Wang(Tongji University); Ming Zhao(Tongji University)"
] |
Early detection and precise location of leakage is of great importance for life-cycle maintenance and management of municipal pipeline system. In the past few years, acoustic emission (AE) techniques have demonstrated to be an excellent tool for on-line leakage detection. Regarding the multi-mode and frequency dispersion characteristics of AE signals propagating along a pipeline, the direct cross-correlation technique that assumes the constant AE propagation velocity does not perform well in practice for acoustic leak location. This paper presents an improved cross-correlation method based on wavelet transform, with due consideration of the frequency dispersion characteristics of AE wave and the contribution of different mode. Laboratory experiments conducted to simulate pipeline gas leakage and investigate the frequency spectrum signatures of AE leak signals. By comparing with the other methods for leak location identification, the feasibility and superiority of the proposed method are verified.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002013485
|
oai_dc
|
A general method for active surface adjustment of cable net structures with smart actuators
|
A general method for active surface adjustment of cable net structures with smart actuators
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zuo-Wei Wang(Xidian University); Tuan-Jie Li(Xidian University)"
] |
Active surface adjustment of cable net structures is becoming significant when large-size cable net structures are widely applied in various fields, especially in satellite antennas. A general-duty adjustment method based on active cables is proposed to achieve active surface adjustment or surface profile reconfiguration of cable net structures. Piezoelectric actuators and voice coil actuators are selected for constructing active cable structures and their simplified mechanical models are proposed. A bilevel optimization model of active surface adjustment is proposed based on the nonlinear static model established by the direct stiffness method. A pattern search algorithm combined with the trust region method is developed to solve this optimization problem. Numerical examples of a parabolic cable net reflector are analyzed and different distribution types of active cables are compared.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002013484
|
oai_dc
|
Optimum design of steel frame structures considering construction cost and seismic damage
|
Optimum design of steel frame structures considering construction cost and seismic damage
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. Kaveh(Iran University of Science and Technology); M. Fahimi-Farzam(Iran University of Science and Technology); M. Kalateh-Ahani(Iran University of Science and Technology)"
] |
Minimizing construction cost and reducing seismic damage are two conflicting objectives in the design of any new structure. In the present work, we try to develop a framework in order to solve the optimum performance-based design problem considering the construction cost and the seismic damage of steel moment-frame structures. The Park-Ang damage index is selected as the seismic damage measure because it is one of the most realistic measures of structural damage. The non-dominated sorting genetic algorithm (NSGA-II) is employed as the optimization algorithm to search the Pareto optimal solutions. To improve the time efficiency of the proposed framework, three simplifying strategies are adopted: first, simplified nonlinear modeling investigating minimum level of structural modeling sophistication; second, fitness approximation decreasing the number of fitness function evaluations; third, wavelet decomposition of earthquake record decreasing the number of acceleration points involved in time-history loading. The constraints of the optimization problem are considered in accordance with Federal Emergency Management Agency\'s (FEMA) recommended seismic design specifications. The results from numerical application of the proposed framework demonstrate the efficiency of the framework in solving the present multi-objective optimization problem.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002013492
|
oai_dc
|
Simulation of superelastic SMA helical springs
|
Simulation of superelastic SMA helical springs
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Reza Mehrabi(Vali-e-Asr University of Rafsanjan); Mohammad Reza Karamooz Ravari(Graduate University of Advanced Technology)"
] |
Shape memory alloy (SMA) helical springs have found a large number of different applications in industries including biomedical devices and actuators. According to the application of SMA springs in different actuators, they are usually under tension and torsion loadings. The ability of SMAs in recovering inelastic strains is due to martensitic phase transformation between austenite and martensite phases. Stress or temperature induced martensite transformation induced of SMAs is a remarkable property which makes SMA springs more superior in comparison with traditional springs. The present paper deals with the simulation of SMA helical spring at room temperature. Three-dimensional phenomenological constitutive model is used to describe superelastic behavior of helical spring. This constitutive model is implemented as a user subroutine through ABAQUS STANDARD (UMAT), and the process of the implementation is presented. Numerical results show that the developed constitutive model provides an appropriate approach to captures the general behavior of SMA helical springs.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART002013489
|
oai_dc
|
Determination of the restoration effect on the structural behavior of masonry arch bridges
|
Determination of the restoration effect on the structural behavior of masonry arch bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A.C. Altunisik(Karadeniz Technical University); A. Bayraktar(Karadeniz Technical University); A.F. Genc(Karadeniz Technical University)"
] |
In this paper, it is aimed to investigate the restoration effect on the structural behavior of masonry arch bridges. Dandalaz masonry arch bridge located on the 4km east of Karacasu town of Aydin, Turkey is selected as a numerical example. The construction year of the bridge is not fully known, but the bridge is dated back to 15th century. Considering the current situation, it can be easily seen that the structural elements such as arch, side walls and timber blocks are heavily damaged and the bridge is unserviceable. Firstly finite element model of the bridge is constituted to reflect the current situation (before restoration) using building survey drawings. After, restoration project is explained and finite element model is reconstituted (after restoration). The structural responses of the bridge are obtained before and after restoration under dead load, live load and dynamic earthquake loads. For both conditions, maximum displacements, maximum-minimum principal stresses and maximum-minimum elastic strains are given with detail using contours diagrams and compared with each other to determine the restoration effect. From the study, it can be seen that the maximum internal forces are consisted under dynamic loads before and after restoration. Also, the restoration projects and studies have important and positive effects on the structural response of the bridge to transfer these structures to future.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001896518
|
oai_dc
|
Spatio-temporal protocol for power-efficient acquisition wireless sensors based SHM
|
Spatio-temporal protocol for power-efficient acquisition wireless sensors based SHM
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Nikola Bogdanovic(University of Patras & C.T.I RU-8); Dimitris Ampeliotis(University of Patras & C.T.I. RU-8); Kostas Berberidis(University of Patras & C.T.I. RU-8); Fabio Casciati(University of Pavia); Jorge Plata-Chaves(University of Patras & C.T.I. RU-8)"
] |
In this work, we address the so-called sensor reachback problem for Wireless Sensor Networks, which consists in collecting the measurements acquired by a large number of sensor nodes into a sink node which has major computational and power capabilities. Focused on applications such as Structural Health Monitoring, we propose a cooperative communication protocol that exploits the spatio-temporal correlations of the sensor measurements in order to save energy when transmitting the information to the sink node in a non-stationary environment. In addition to cooperative communications, the protocol is based on two well-studied adaptive filtering techniques, Least Mean Squares and Recursive Least Squares, which trade off computational complexity and reduction in the number of transmissions to the sink node. Finally, experiments with real acceleration measurements, obtained from the Canton Tower in China, are included to show the effectiveness of the proposed method.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001896520
|
oai_dc
|
Output–error state–space identification of vibrating structures using evolution strategies: a benchmark study
|
Output–error state–space identification of vibrating structures using evolution strategies: a benchmark study
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Vasilis K. Dertimanis(Cyprus University of Technology)"
] |
In this study, four widely accepted and used variants of Evolution Strategies (ES) are adapted and applied to the output–error state-space identification problem. The selection of ES is justified by prior strong indication of superior performance to similar problems, over alternatives like Genetic Algorithms (GA) or Evolutionary Programming (EP). The ES variants that are being tested are (i) the (1+1)–ES, (ii) the (u/p+y)–o–SA–ES, (iii) the (ui,y)–o–SA–ES, and (iv) the (uw,y)–CMA–ES. The study is based on a six–degree–of–freedom (DOF) structural model of a shear building that is characterized by light damping (up to 5%). The envisaged analysis is taking place through Monte Carlo experiments under two different excitation types (stationary / non–stationary) and the applied ES are assessed in terms of (i) accurate modal parameters extraction, (ii) statistical consistency, (iii) performance under noise–corrupted data, and (iv) performance under non–stationary data. The results of this suggest that ES are indeed competitive alternatives in the non–linear state-space estimation problem and deserve further attention.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001896522
|
oai_dc
|
Layout optimization of wireless sensor networks for structural health monitoring
|
Layout optimization of wireless sensor networks for structural health monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Khash-Erdene Jalsan(Swiss Federal Laboratories); Rohan N. Soman(Cyprus University); Kallirroi Flouri(Swiss Federal Laboratories); Marios A. Kyriakides(Cyprus University); Glauco Feltrin(Swiss Federal Laboratories); Toula Onoufriou(Cyprus University)"
] |
Node layout optimization of structural wireless systems is investigated as a means to prolong the network lifetime without, if possible, compromising information quality of the measurement data. The trade-off between these antagonistic objectives is studied within a multi-objective layout optimization framework. A Genetic Algorithm is adopted to obtain a set of Pareto-optimal solutions from which the end user can select the final layout. The information quality of the measurement data collected from a heterogeneous WSN is quantified from the placement quality indicators of strain and acceleration sensors. The network lifetime or equivalently the network energy consumption is estimated through WSN simulation that provides realistic results by capturing the dynamics of the wireless communication protocols. A layout optimization study of a monitoring system on the Great Belt Bridge is conducted to evaluate the proposed approach. The placement quality of strain gauges and accelerometers is obtained as a ratio of the Modal Clarity Index and Mode Shape Expansion values that are computed from a Finite Element model of the monitored bridge. To estimate the energy consumption of the WSN platform in a realistic scenario, we use a discrete-event simulator with stochastic communication models. Finally, we compare the optimization results with those obtained in a previous work where the network energy consumption is obtained via deterministic communication models.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001896525
|
oai_dc
|
Multi-type, multi-sensor placement optimization for structural health monitoring of long span bridges
|
Multi-type, multi-sensor placement optimization for structural health monitoring of long span bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rohan N. Soman(Cyprus University); Toula Onoufriou(Cyprus University); Marios A. Kyriakides(Cyprus University); Renos A. Votsis(Cyprus University); Christis Z. Chrysostomou(Cyprus University)"
] |
The paper presents a multi-objective optimization strategy for a multi-type sensor placement for Structural Health Monitoring (SHM) of long span bridges. The problem is formulated for simultaneous placement of strain sensors and accelerometers (heterogeneous network) based on application demands for SHM system. Modal Identification (MI) and Accurate Mode Shape Expansion (AMSE) were chosen as the application demands for SHM. The optimization problem is solved through the use of integer Genetic Algorithm (GA) to maximize a common metric to ensure adequate MI and AMSE. The performance of the joint optimization problem solved by GA is compared with other established methods for homogenous sensor placement. The results indicate that the use of a multi-type sensor system can improve the quality of SHM. It has also been demonstrated that use of GA improves the overall quality of the sensor placement compared to other methods for optimization of sensor placement.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001911495
|
oai_dc
|
A wavelet finite element-based adaptive-scale damage detection strategy
|
A wavelet finite element-based adaptive-scale damage detection strategy
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wen-Yu He(The Hong Kong Polytechnic University); Songye Zhu(The Hong Kong Polytechnic University); Wei-Xin Ren(Hefei University of Technology)"
] |
This study employs a novel beam-type wavelet finite element model (WFEM) to fulfill an adaptive-scale damage detection strategy in which structural modeling scales are not only spatially varying but also dynamically changed according to actual needs. Dynamical equations of beam structures are derived in the context of WFEM by using the second-generation cubic Hermite multiwavelets as interpolation functions. Based on the concept of modal strain energy, damage in beam structures can be detected in a progressive manner: the suspected region is first identified using a low-scale structural model and the more accurate location and severity of the damage can be estimated using a multi-scale model with local refinement in the suspected region. Although this strategy can be implemented using traditional finite element methods, the multi-scale and localization properties of the WFEM considerably facilitate the adaptive change of modeling scales in a multi-stage process. The numerical examples in this study clearly demonstrate that the proposed damage detection strategy can progressively and efficiently locate and quantify damage with minimal computation effort and a limited number of sensors.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001911507
|
oai_dc
|
Electrical signal characteristics of conductive asphalt concrete in the process of fatigue cracking
|
Electrical signal characteristics of conductive asphalt concrete in the process of fatigue cracking
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Qun Yang(Tongji University); Ping Wang(Tongji University); Xu Li(Tongji University); Hong-Wei Zhang(Tongji University)"
] |
As a kind of intelligent materials, conductive asphalt concrete has a broad application prospect including melting ice and snow on the pavement, closing cracks in asphalt concrete, sensing pavement damage, and so on. Conductive pavement will be suffered from fatigue failure as conventional pavement in the process of service, and this fatigue damage of internal structure can be induced by electrical signal output. The characteristics of electrical signal variation of conductive asphalt concrete in the process of fatigue cracking were researched in this paper. The whole process was clearly divided into three stages according to resistance changes, and the development of fatigue damage wasn\'t obvious in stage I and stage II, while in stage III, the synchronicity between the resistance and damage began to appear. Thus, fatigue damage variable D and initial damage value D0 represented by the functions of resistance were introduced in stage III. After calculating the initial damage value D0 under different stress levels, it was concluded that the initial damage value D0 had no noticeable change, just ranged between 0.24 and 0.25. This value represented a critical point which could be used to inform the repair time of early fatigue damage in the conductive asphalt pavement.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001911499
|
oai_dc
|
Long run ambient noise recording for a masonry medieval tower
|
Long run ambient noise recording for a masonry medieval tower
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S. Casciati(University of Catania at Siracusa); A. Tento(Istituto per la Dinamica dei Processi Ambientali); S. Casciati(University of Catania at Siracusa); R. Daminelli(Istituto per la Dinamica dei Processi Ambientali)"
] |
Ambient vibration techniques are nowadays a very popular tool to assess dynamic properties of buildings. Due to its non destructive character, this method is particularly valuable, especially for health monitoring of historical monuments. The present ambient vibration experiment consists on the evaluation of vibration modes of a Medieval tower. Situated in Soncino (close to Cremona, in the Northern Italian region named Lombardia), the tower of 41.5 meters height has been monitored by seismometers located at different points inside the structure. Spectral ratios of the recorded ambient vibrations clearly identify a fundamental mode at about 1 Hz, with a slight difference in the two horizontal components. A second mode is also evidenced at approx 4-5 Hz, with a moderate degree of uncertainty. The records of a ML 4.4 earthquake, occurred during the monitoring period, confirm the information obtained by microtremor analysis. Daily variations of both 1st and 2nd mode were detected: these variations, of an amount up to 2%, seem to be well related with the temperature
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001911509
|
oai_dc
|
Damages of minarets during Erciş and Edremit Earthquakes, 2011 in Turkey
|
Damages of minarets during Erciş and Edremit Earthquakes, 2011 in Turkey
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ahmet Can Altunişik(Karadeniz Technical University); Alemdar Bayraktar(Karadeniz Technical University); Murat Muvafik(Yüzüncü Yıl University)"
] |
This paper illustrates the damages of reinforced concrete and masonry minarets during October 23 (Erciş) and November 9 (Edremit), 2011 Van earthquakes in Turkey. Erciş and Edremit are townships located 90km and 18km from Van city center in Turkey, respectively. Ground accelerations and response spectrums for these earthquakes are given in this paper. A total of 63 reinforced concrete and masonry minarets are heavily damaged or collapsed in the city center and villages nearby after both earthquakes. Because of the fact that there is no Turkish standard and specification directly related to design of minarets, nearly all of the constructions are carried out by workers using only their own technical knowledge. So, all of the non-engineering reinforced concrete and masonry minarets completely collapsed or damaged heavily. From the study, it is seen that the damages are due to several reasons such as site effect, location, and length of the fault, reduction in cross section and formation of the discontinuity, use of plain reinforcement steel, use of concrete with insufficient strength, existence of short lap splices and incorrect end hook angle, larger mass and stiffness concentrations on some region, longitudinal reinforcements discontinuity, cracks at the cylindrical body, and damage of spire and end ornament. In addition to these reasons, the two earthquakes hit the minarets within seventeen days, causing progressive damage. So, the existing design and construction practices should be improved to provide sufficient earthquake performance. Also, it is recommended that there should be a safe distance between the minaret and surrounding structures to reduce the loose of life after earthquake
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001911497
|
oai_dc
|
DOB-based piezoelectric vibration control for stiffened plate considering accelerometer measurement noise
|
DOB-based piezoelectric vibration control for stiffened plate considering accelerometer measurement noise
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Shengquan Li(Yangzhou University); Rong Zhao(Yangzhou University); Yueping Mo(Yangzhou University); Zhenyu Sun(Yangzhou University); Juan Li(Southeast University)"
] |
This paper presents a composite control strategy for the active suppression of vibration due to the unknown disturbances, such as external excitation, harmonic effects and control spillover, as well as high-frequency accelerometer measurement noise in the all-clamped stiffened plate. The proposed composite control action based on the modal approach, consists of two contributions including feedback part and feedforward part. The feedback part is the well-known PID controller, which is widely used to increase the structure damping and improve its dynamic performance close to the resonance frequencies. In order to get better performance for vibration suppression, the weight matrixes is optimized by chaos sequence. Then an improved disturbance observer (IDOB) as the feedforward compensation part is developed to enhance the vibration suppression performance of PID under various disturbances and uncertainties. The proposed IDOB can simultaneously estimate the various disturbances dynamically as well as measurement noise acting on the system and suppress them by feedforward compensation design. A rigorous analysis is also given to show why the IDOB can effectively suppress the unknown disturbances and measurement noise. In order to verify the proposed composite control algorithm (IDOB-PID), the dSPACE real-time simulation platform is used and an experimental platform for the all-clamped stiffened plate active vibration control system is set up. The experimental results demonstrate the effectiveness, practicality and strong anti-disturbances ability of the proposed control strategy.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001911498
|
oai_dc
|
Positioning and vibration suppression for multiple degrees of freedom flexible structure by genetic algorithm and input shaping
|
Positioning and vibration suppression for multiple degrees of freedom flexible structure by genetic algorithm and input shaping
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"J. Lin(Chien Hsin University of Science and Technology); C.B. Chiang(Chien Hsin University of Science and Technology)"
] |
The main objective of this paper is to develop an innovative methodology for the vibration suppression control of the multiple degrees-of-freedom (MDOF) flexible structure. The proposed structure represented in this research as a clamped-free-free-free truss type plate is rotated by motors. The controller has two loops for tracking and vibration suppression. In addition to stabilizing the actual system, the proposed feedback control is based on a genetic algorithm (GA) to seek the primary optimal control gain for tracking and stabilization purposes. Moreover, input shaping is introduced for the control scheme that limits motion-induced elastic vibration by shaping the reference command. Experimental results are presented, demonstrating that, in the control loop, roll and yaw angles track control and elastic mode stabilization. It was also demonstrated that combining the input shaper with the proportional-integral-derivative (PID) feedback method has been shown to yield improved performance in controlling the flexible structure system. The broad range of problems discussed in this research is valuable in civil, mechanical, and aerospace engineering for flexible structures with MDOM motion.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001911494
|
oai_dc
|
Electromechanical analysis of 2-2 cement-based piezoelectric transducers in series electrically
|
Electromechanical analysis of 2-2 cement-based piezoelectric transducers in series electrically
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jianjun Wang(Beijing Jiaotong University); Zhifei Shi(Beijing Jiaotong University)"
] |
his paper aims to present the analytical solutions of 2-2 cement based piezoelectric transducers in series electrically based on the theory of piezo-elastic dynamics. The solutions of two different kinds of 2-2 cement based piezoelectric transducers under external harmonic load are obtained by using the displacement method. The effects of electrical connection of piezoelectric layers, loading frequency, thickness and distance of piezoelectric layers on the characteristics of the transducers are discussed. Comparisons with other related experimental investigations are also given, and good agreement is found. The proposed 2-2 cement based piezoelectric transducers have a great potential application in monitoring structural health in civil engineering and capturing mechanical energy or monitoring train-running safety in railway system and traffic safety in road system.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001911496
|
oai_dc
|
Fatigue damage monitoring and evolution for basalt fiber reinforced polymer materials
|
Fatigue damage monitoring and evolution for basalt fiber reinforced polymer materials
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hui Li(Harbin Institute of Technology); Wentao Wang(Harbin Institute of Technology); Wensong Zhou(Harbin Institute of Technology)"
] |
A newly developed method based on energy is presented to study the damage pattern of FRP material. Basalt fiber reinforced polymer (BFRP) is employed to monitor the damage under fatigue loading. In this study, acoustic emission technique (AE) combined with scanning electronic microscope (SEM) technique is employed to monitor the damage evolution of the BFRP specimen in an approximate continuous scanning way. The AE signals are analyzed based on the wavelet transform, and the analyses are confirmed by SEM images. Several damage patterns of BFRP material, such as matrix cracking, delamination, fiber fracture and their combinations, are identified through the experiment. According to the results, the cumulative energy (obtained from wavelet coefficients) of various damage patterns are closely related to the damage evolution of the BFRP specimens during the entire fatigue tests. It has been found that the proposed technique can effectively distinguish different damage patterns of FRP materials and describe the fatigue damage evolution.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001911500
|
oai_dc
|
Bearing fault detection through multiscale wavelet scalogram-based SPC
|
Bearing fault detection through multiscale wavelet scalogram-based SPC
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"정욱(Dongguk University-Seoul); Bong-Hwan Koh(Dongguk University-Seoul)"
] |
Vibration-based fault detection and condition monitoring of rotating machinery, using statistical process control (SPC) combined with statistical pattern recognition methodology, has been widely investigated by many researchers. In particular, the discrete wavelet transform (DWT) is considered as a powerful tool for feature extraction in detecting fault on rotating machinery. Although DWT significantly reduces the dimensionality of the data, the number of retained wavelet features can still be significantly large. Then, the use of standard multivariate SPC techniques is not advised, because the sample covariance matrix is likely to be singular, so that the common multivariate statistics cannot be calculated. Even though many feature-based SPC methods have been introduced to tackle this deficiency, most methods require a parametric distributional assumption that restricts their feasibility to specific problems of process control, and thus limit their application. This study proposes a nonparametric multivariate control chart method, based on multiscale wavelet scalogram (MWS) features, that overcomes the limitation posed by the parametric assumption in existing SPC methods. The presented approach takes advantage of multi-resolution analysis using DWT, and obtains MWS features with significantly low dimensionality. We calculate Hotelling\' s T2-type monitoring statistic using MWS, which has enough damage-discrimination ability. A bootstrap approach is used to determine the upper control limit of the monitoring statistic, without any distributional assumption. Numerical simulations demonstrate the performance of the proposed control charting method, under various damage-level scenarios for a bearing system.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001911501
|
oai_dc
|
A new method to detect cracks in plate-like structures with though-thickness cracks
|
A new method to detect cracks in plate-like structures with though-thickness cracks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jiawei Xiang(Wenzhou University); Yongying Jiang(Wenzhou University); Udo Nackenhorst(Leibniz Universität Hannover); Yanxue Wang(Guilin University of Electronic Technology); Haifeng Gao(Wenzhou University); Yumin He(Xi'an University of Architecture and Technology)"
] |
In this paper, a simple two-step method for structural vibration-based health monitoring for beam-like structures have been extended to plate-like structures with though-thickness cracks. Crack locations and severities of plate-like structures are detected using a hybrid approach. The interval wavelet transform is employed to extract crack singularity locations from mode shape and support vector regression (SVR) is applied to predict crack serviettes form crack severity detection database (the relationship of natural frequencies and crack serviettes) using several natural frequencies as inputs. Of particular interest is the natural frequencies estimation for cracked plate-like structures using Rayleigh quotient. Only the natural frequencies and mode shapes of intact structures are needed to calculate the natural frequencies of cracked plate-like structures using a simple formula. The crack severity detection database can be easily obtained with this formula. The hybrid method is investigated using numerical simulation and its validity of the usage of interval wavelet transform and SVR are addressed.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001911503
|
oai_dc
|
Novel approach for early damage detection on rotor blades of wind energy converters
|
Novel approach for early damage detection on rotor blades of wind energy converters
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Stephan Zerbst(Leibniz Universität Hannover); Stavroula Tsiapoki(Leibniz Universität Hannover); Raimund Rolfes(Leibniz Universität Hannover)"
] |
Within this paper a new approach for early damage detection in rotor blades of wind energy converters is presented, which is shown to have a more sensitive reaction to damage than eigenfrequency-based methods. The new approach is based on the extension of Gasch\' s proportionality method, according to which maximum oscillation velocity and maximum stress are proportional by a factor, which describes the dynamic behavior of the structure. A change in the proportionality factor can be used as damage indicator. In addition, a novel deflection sensor was developed, which was specifically designed for use in wind turbine rotor blades. This deflection sensor was used during the experimental tests conducted for the measurement of the blade deflection. The method was applied on numerical models for different damage cases and damage extents. Additionally, the method and the sensing concept were applied on a real 50.8 m blade during a fatigue test in the edgewise direction. During the test, a damage of 1.5 m length was induced on the upper trailing edge bondline. Both the initial damage and the increase of its length were successfully detected by the decrease of the proportionality factor. This decrease coincided significantly with the decrease of the factor calculated from the numerical analyses.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001911505
|
oai_dc
|
Damping and frequency changes induced by increasing levels of inelastic seismic demand
|
Damping and frequency changes induced by increasing levels of inelastic seismic demand
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Diego A. Aguirre(University of Puerto Rico at Mayagüez); Luis A. Montejo(University of Puerto Rico at Mayagüez)"
] |
The objective in this research is to determine the feasibility of using changes on the dynamic properties of a reinforced concrete (RC) structure to identify different levels of seismic induced damage. Damping ratio and natural frequency changes in a RC bridge column are analyzed using different signal processing techniques like Hilbert Transforms, Random Decrement and Wavelet Transforms. The data used in the analysis was recorded during a full-scale RC bridge column shake table test. The structure was subjected to ten earthquake excitations that induced different levels of inelastic demand on the column. In addition, low-intensity white noises were applied to the column in-between earthquakes. The results obtained show that the use of the damping ratio and natural frequency of vibration as damage indicators is arguable.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001876465
|
oai_dc
|
Drive-by bridge inspection from three different approaches
|
Drive-by bridge inspection from three different approaches
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"C.W. Kim(Kyoto University); R. Isemoto(Kyoto University); P.J. McGetrick(Kyoto University); M. Kawatani(Kobe University); E.J. OBrien(University College Dublin)"
] |
This study presents a vibration-based health monitoring strategy for short span bridges utilizing an inspection vehicle. How to screen the health condition of short span bridges in terms of a drive-by bridge inspection is described. Feasibility of the drive-by bridge inspection is investigated through a scaled laboratory moving vehicle experiment. The feasibility of using an instrumented vehicle to detect the natural frequency and changes in structural damping of a model bridge was observed. Observations also demonstrated the possibility of diagnosis of bridges by comparing patterns of identified bridge dynamic parameters through periodical monitoring. It was confirmed that the moving vehicle method identifies the damage location and severity well.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001876466
|
oai_dc
|
Constructing the mode shapes of a bridge from a passing vehicle: a theoretical study
|
Constructing the mode shapes of a bridge from a passing vehicle: a theoretical study
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y.B. Yang(National Taiwan University); Y.C. Li(National Taiwan University); K.C. Chang(Kyoto University)"
] |
This paper presents a theoretical algorithm for constructing the mode shapes of a bridge from the dynamic responses of a test vehicle moving over the bridge. In comparison with those approaches that utilize a limited number of sensors deployed on the bridge, the present approach can offer much more spatial information, as well as higher resolution in mode shapes, since the test vehicle can receive the vibration characteristics of each point during its passage on the bridge. Basically only one or few sensors are required to be installed on the test vehicle. Factors that affect the accuracy of the present approach for constructing the bridge mode shapes are studied, including the vehicle speed, random traffic, and road surface roughness. Through numerical simulations, the present approach is verified to be feasible under the condition of constant and low vehicle speeds.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001876463
|
oai_dc
|
Variability in bridge frequency induced by a parked vehicle
|
Variability in bridge frequency induced by a parked vehicle
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"K.C. Chang(Kyoto University); C.W. Kim(Kyoto University); Sudanna Borjigin(Kyoto University)"
] |
The natural frequency of a bridge is an important parameter in many engineering applications such as bridge seismic design and modal-based bridge health monitoring. The natural frequency of a bridge vibrating alone may differ from that vibrating along with a vehicle. Although such vehicle-induced variability in bridge frequency is revealed in several experimental and numerical simulation studies, few attempts have been made on the theoretical escriptions. In this study, both theoretically and experimentally, the variability in the bridge frequency induced by a parked vehicle is verified, and is therefore suggested to be considered in bridge-related engineering, especially for those cases with near vehicle-bridge resonance conditions or with large vehicle-to-bridge mass ratios. Moreover, the variability ranges could be estimated by an analytical formula presented herein.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001876473
|
oai_dc
|
A structural damage detection approach using train-bridge interaction analysis and soft computing methods
|
A structural damage detection approach using train-bridge interaction analysis and soft computing methods
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xingwen He(Hokkaido University); Mitsuo Kawatani(Kobe University); Toshiro Hayashikawa(Hokkaido University); Chul-Woo Kim(Kobe University,); F. Necati Catbas(University of Central Florida); Hitoshi Furuta(Kansai University)"
] |
In this study, a damage detection approach using train-induced vibration response of the bridge is proposed, utilizing only direct structural analysis by means of introducing soft computing methods. In this approach, the possible damage patterns of the bridge are assumed according to theoretical and empirical considerations at first. Then, the running train-induced dynamic response of the bridge under a certain damage pattern is calculated employing a developed train-bridge interaction analysis program. When the calculated result is most identical to the recorded response, this damage pattern will be the solution. However, owing to the huge number of possible damage patterns, it is extremely time-consuming to calculate the bridge responses of all the cases and thus difficult to identify the exact solution quickly. Therefore, the soft computing methods are introduced to quickly solve the problem in this approach. The basic concept and process of the proposed approach are presented in this paper, and its feasibility is numerically investigated using two different train models and a simple girder bridge model.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001876469
|
oai_dc
|
A drive-by inspection system via vehicle moving force identification
|
A drive-by inspection system via vehicle moving force identification
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"P.J. McGetrick(Queen's University Belfast); E.J. OBrien(University College Dublin); A. González(University College Dublin)"
] |
This paper presents a novel method to carry out monitoring of transport infrastructure such as pavements and bridges through the analysis of vehicle accelerations. An algorithm is developed for the identification of dynamic vehicle-bridge interaction forces using the vehicle response. Moving force identification theory is applied to a vehicle model in order to identify these dynamic forces between the vehicle and the road and/or bridge. A coupled half-car vehicle-bridge interaction model is used in theoretical simulations to test the effectiveness of the approach in identifying the forces. The potential of the method to identify the global bending stiffness of the bridge and to predict the pavement roughness is presented. The method is tested for a range of bridge spans using theoretical simulations and the influences of road roughness and signal noise on the accuracy of the results are investigated.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001876471
|
oai_dc
|
Indirect structural health monitoring of a simplified laboratory-scale bridge model
|
Indirect structural health monitoring of a simplified laboratory-scale bridge model
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Fernando Cerda(Universidad de Concepción); Siheng Chen(Carnegie Mellon University); Jacobo Bielak(Carnegie Mellon University); James H. Garrett(Carnegie Mellon University); Piervincenzo Rizzo(University of Pittsburgh); Jelena Kovačević(Carnegie Mellon University)"
] |
An indirect approach is explored for structural health bridge monitoring allowing for wide, yet cost-effective, bridge stock coverage. The detection capability of the approach is tested in a laboratory setting for three different reversible proxy types of damage scenarios: changes in the support conditions (rotational restraint), additional damping, and an added mass at the midspan. A set of frequency features is used in conjunction with a support vector machine classifier on data measured from a passing vehicle at the wheel and suspension levels, and directly from the bridge structure for comparison. For each type of damage, four levels of severity were explored. The results show that for each damage type, the classification accuracy based on data measured from the passing vehicle is, on average, as good as or better than the classification accuracy based on data measured from the bridge. Classification accuracy showed a steady trend for low (1-1.75 m/s) and high vehicle speeds (2-2.75 m/s), with a decrease of about 7% for the latter. These results show promise towards a highly mobile structural health bridge monitoring system for wide and cost-effective bridge stock coverage.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001876461
|
oai_dc
|
Damage assessment of a bridge based on mode shapes estimated by responses of passing vehicles
|
Damage assessment of a bridge based on mode shapes estimated by responses of passing vehicles
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yoshinobu Oshima(Kyoto University); Kyosuke Yamamoto(University of Tsukuba); Kunitomo Sugiura(University of Tsukuba)"
] |
In this study, an indirect approach is developed for assessing the state of a bridge on the basis of mode shapes estimated by the responses of passing vehicles. Two types of damages, i.e., immobilization of a support and decrease in beam stiffness at the center, are evaluated with varying degrees of road roughness and measurement noise. The assessment theory\'s feasibility is verified through numerical simulations of interactive vibration between a two-dimensional beam and passing vehicles modeled simply as sprung mass. It is determined that the damage state can be recognized by the estimated mode shapes when the beam incurs severe damage, such as immobilization of rotational support, and the responses contain no noise. However, the developed theory has low robustness against noise. Therefore, numerous measurements are needed for damage identification when the measurement is contaminated with noise.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001938026
|
oai_dc
|
Real-time hybrid simulation of a multi-story wood shear wall with first-story experimental substructure incorporating a rate-dependent seismic energy dissipation device
|
Real-time hybrid simulation of a multi-story wood shear wall with first-story experimental substructure incorporating a rate-dependent seismic energy dissipation device
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xiaoyun Shao(Western Michigan University); John van de Lindt(Colorado State University); Pouria Bahmani(Colorado State University); Weichiang Pang(Clemson University); Ershad Ziaei(Clemson University); Michael Symans(Rensselaer Polytechnic InstituteTroy); Jingjing Tian(Rensselaer Polytechnic InstituteTroy); Thang Dao(University of Alabama)"
] |
Real-time hybrid simulation (RTHS) of a stacked wood shear wall retrofitted with a rate-dependent seismic energy dissipation device (viscous damper) was conducted at the newly constructed Structural Engineering Laboratory at the University of Alabama. This paper describes the implementation process of the RTHS focusing on the controller scheme development. An incremental approach was adopted starting from a controller for the conventional slow pseudodynamic hybrid simulation and evolving to the one applicable for RTHS. Both benchmark- scale and full-scale tests are discussed to provide a roadmap for future RTHS implementation at different laboratories and/or on different structural systems. The developed RTHS controller was applied to study the effect of a rate-dependent energy dissipation device on the seismic performance of a multi-story wood shear wall system. The test specimen, setup, program and results are presented with emphasis given to inter-story drift response. At 100% DBE the RTHS showed that the multi-story shear wall with the damper had 32% less inter-story drift and was noticeably less damaged than its un-damped specimen counterpart.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001938031
|
oai_dc
|
Model updating with constrained unscented Kalman filter for hybrid testing
|
Model updating with constrained unscented Kalman filter for hybrid testing
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Bin Wu(Harbin Institute of Technology); Tao Wang(Harbin Institute of Technology)"
] |
The unscented Kalman filter (UKF) has been developed for nonlinear model parametric identification, and it assumes that the model parameters are symmetrically distributed about their mean values without any constrains. However, the parameters in many applications are confined within certain ranges to make sense physically. In this paper, a constrained unscented Kalman filter (CUKF) algorithm is proposed to improve accuracy of numerical substructure modeling in hybrid testing. During hybrid testing, the numerical models of numerical substructures which are assumed identical to the physical substructures are updated online with the CUKF approach based on the measurement data from physical substructures. The CUKF method adopts sigma points (i.e., sample points) projecting strategy, with which the positions and weights of sigma points violating constraints are modified. The effectiveness of the proposed hybrid testing method is verified by pure numerical simulation and real-time as well as slower hybrid tests with nonlinear specimens. The results show that the new method has better accuracy compared to conventional hybrid testing with fixed numerical model and hybrid testing based on model updating with UKF.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001938039
|
oai_dc
|
Establishing a stability switch criterion for effective implementation of real-time hybrid simulation
|
Establishing a stability switch criterion for effective implementation of real-time hybrid simulation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Amin Maghareh(Purdue University); Arun Prakash(Purdue University); Shirley J. Dyke(Purdue University); Jeffrey F. Rhoads(Purdue University)"
] |
Real-time hybrid simulation (RTHS) is a promising cyber-physical technique used in the experimental evaluation of civil infrastructure systems subject to dynamic loading. In RTHS, the response of a structural system is simulated by partitioning it into physical and numerical substructures, and coupling at the interface is achieved by enforcing equilibrium and compatibility in real-time. The choice of partitioning parameters will influence the overall success of the experiment. In addition, due to the dynamics of the transfer system, communication and computation delays, the feedback force signals are dependent on the system state subject to delay. Thus, the transfer system dynamics must be accommodated by appropriate actuator controllers. In light of this, guidelines should be established to facilitate successful RTHS and clearly specify: (i) the minimum requirements of the transfer system control, (ii) the minimum required sampling frequency, and (iii) the most effective ways to stabilize an unstable simulation due to the limitations of the available transfer system. The objective of this paper is to establish a stability switch criterion due to systematic experimental errors. The RTHS stability switch criterion will provide a basis for the partitioning and design of successful RTHS
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001938035
|
oai_dc
|
Effects of interface delay in real-time dynamic substructuring tests on a cable for cable-stayed bridge
|
Effects of interface delay in real-time dynamic substructuring tests on a cable for cable-stayed bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Maria Rosaria Marsico(University of Exeter)"
] |
Real-time dynamic substructuring tests have been conducted on a cable-deck system. The cable is representative of a full scale cable for a cable-stayed bridge and it interacts with a deck, numerically modelled as a single-degree-of-freedom system. The purpose of exciting the inclined cable at the bottom is to identify its nonlinear dynamics and to mark the stability boundary of the semi-trivial solution. The latter physically corresponds to the point at which the cable starts to have an out-of-plane response when both input and previous response were in-plane. The numerical and the physical parts of the system interact through a transfer system, which is an actuator, and the input signal generated by the numerical model is assumed to interact instantaneously with the system. However, only an ideal system manifests a perfect correspondence between the desired signal and the applied signal. In fact, the transfer system introduces into the desired input signal a delay, which considerably affects the feedback force that, in turn, is processed to generate a new input. The effectiveness of the control algorithm is measured by using the synchronization technique, while the online adaptive forward prediction algorithm is used to compensate for the delay error, which is present in the performed tests. The response of the cable interacting with the deck has been experimentally observed, both in the presence of delay and when delay is compensated for, and it has been compared with the analytical model. The effects of the interface delay in real-time dynamic substructuring tests conducted on the cable-deck system are extensively discussed.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001938041
|
oai_dc
|
An effective online delay estimation method based on a simplified physical system model for real-time hybrid simulation
|
An effective online delay estimation method based on a simplified physical system model for real-time hybrid simulation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zhen Wang(Harbin Institute of Technology); Bin Wu(Harbin Institute of Technology); Guoshan Xu(Harbin Institute of Technology); Yong Ding(Harbin Institute of Technology); Oreste S. Bursi(University of Trento)"
] |
Real-Time Hybrid Simulation (RTHS) is a novel approach conceived to evaluate dynamic responses of structures with parts of a structure physically tested and the remainder parts numerically modelled. In RTHS, delay estimation is often a precondition of compensation; nonetheless, system delay may vary during testing. Consequently, it is sometimes necessary to measure delay online. Along these lines, this paper proposes an online delay estimation method using least-squares algorithm based on a simplified physical system model, i.e., a pure delay multiplied by a gain reflecting amplitude errors of physical system control. Advantages and disadvantages of different delay estimation methods based on this simplified model are firstly discussed. Subsequently, it introduces the least-squares algorithm in order to render the estimator based on Taylor series more practical yet effective. As a result, relevant parameter choice results to be quite easy. Finally in order to verify performance of the proposed method, numerical simulations and RTHS with a buckling-restrained brace specimen are carried out. Relevant results show that the proposed technique is endowed with good convergence speed and accuracy, even when measurement noises and amplitude errors of actuator control are present.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001938028
|
oai_dc
|
Compensation techniques for experimental errors in real-time hybrid simulation using shake tables
|
Compensation techniques for experimental errors in real-time hybrid simulation using shake tables
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Narutoshi Nakata(Clarkson University); Matthew Stehman(Johns Hopkins University)"
] |
Substructure shake table testing is a class of real-time hybrid simulation (RTHS). It combines shake table tests of substructures with real-time computational simulation of the remaining part of the structure to assess dynamic response of the entire structure. Unlike in the conventional hybrid simulation, substructure shake table testing imposes acceleration compatibilities at substructure boundaries. However, acceleration tracking of shake tables is extremely challenging, and it is not possible to produce perfect acceleration tracking without time delay. If responses of the experimental substructure have high correlation with ground accelerations, response errors are inevitably induced by the erroneous input acceleration. Feeding the erroneous responses into the RTHS procedure will deteriorate the simulation results. This study presents a set of techniques to enable reliable substructure shake table testing. The developed techniques include compensation techniques for errors induced by imperfect input acceleration of shake tables, model-based actuator delay compensation with state observer, and force correction to eliminate process and measurement noises. These techniques are experimentally investigated through RTHS using a uni-axial shake table and three-story steel frame structure at the Johns Hopkins University. The simulation results showed that substructure shake table testing with the developed compensation techniques provides an accurate and reliable means to simulate the dynamic responses of the entire structure under earthquake excitations.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001938033
|
oai_dc
|
Logic circuit design for high-speed computing of dynamic response in real-time hybrid simulation using FPGA-based system
|
Logic circuit design for high-speed computing of dynamic response in real-time hybrid simulation using FPGA-based system
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Akira Igarashi(Kyoto University)"
] |
One of the issues in extending the range of applicable problems of real-time hybrid simulation is the computation speed of the simulator when large-scale computational models with a large number of DOF are used. In this study, functionality of real-time dynamic simulation of MDOF systems is achieved by creating a logic circuit that performs the step-by-step numerical time integration of the equations of motion of the system. The designed logic circuit can be implemented to an FPGA-based system; FPGA (Field Programmable Gate Array) allows large-scale parallel computing by implementing a number of arithmetic operators within the device. The operator splitting method is used as the numerical time integration scheme. The logic circuit consists of blocks of circuits that perform numerical arithmetic operations that appear in the integration scheme, including addition and multiplication of floating-point numbers, registers to store the intermediate data, and data busses connecting these elements to transmit various information including the floating-point numerical data among them. Case study on several types of linear and nonlinear MDOF system models shows that use of resource sharing in logic synthesis is crucial for effective application of FPGA to real-time dynamic simulation of structural response with time step interval of 1 ms.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001938034
|
oai_dc
|
Development, implementation and verification of a user configurable platform for real-time hybrid simulation
|
Development, implementation and verification of a user configurable platform for real-time hybrid simulation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ali Ashasi-Sorkhabi(University of Toronto); Oya Mercan(University of Toronto)"
] |
This paper presents a user programmable computational/control platform developed to conduct real-time hybrid simulation (RTHS). The architecture of this platform is based on the integration of a real-time controller and a field programmable gate array (FPGA).This not only enables the user to apply user-defined control laws to control the experimental substructures, but also provides ample computational resources to run the integration algorithm and analytical substructure state determination in real-time. In this platform the need for SCRAMNet as the communication device between real-time and servo-control workstations has been eliminated which was a critical component in several former RTHS platforms. The accuracy of the servo-hydraulic actuator displacement control, where the control tasks get executed on the FPGA was verified using single-degree-of-freedom (SDOF) and 2 degrees-of-freedom (2DOF) experimental substructures. Finally, the functionality of the proposed system as a robust and reliable RTHS platform for performance evaluation of structural systems was validated by conducting real-time hybrid simulation of a three story nonlinear structure with SDOF and 2DOF experimental substructures. Also, tracking indicators were employed to assess the accuracy of the results.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001938030
|
oai_dc
|
Feedforward actuator controller development using the backward-difference method for real-time hybrid simulation
|
Feedforward actuator controller development using the backward-difference method for real-time hybrid simulation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Brian M. Phillips(University of Maryland); Shuta Takada(University of Tokyo); Yozo Fujino(University of Tokyo); B.F. Spencer, Jr(University of Illinois)"
] |
Real-time hybrid simulation (RTHS) has emerged as an important tool for testing large and complex structures with a focus on rate-dependent specimen behavior. Due to the real-time constraints, accurate dynamic control of servo-hydraulic actuators is required. These actuators are necessary to realize the desired displacements of the specimen, however they introduce unwanted dynamics into the RTHS loop. Model-based actuator control strategies are based on linearized models of the servo-hydraulic system, where the controller is taken as the model inverse to effectively cancel out the servo-hydraulic dynamics (i.e., model-based feedforward control). An accurate model of a servo-hydraulic system generally contains more poles than zeros, leading to an improper inverse (i.e., more zeros than poles). Rather than introduce additional poles to create a proper inverse controller, the higher order derivatives necessary for implementing the improper inverse can be calculated from available information. The backward-difference method is proposed as an alternative to discretize an improper continuous time model for use as a feedforward controller in RTHS. This method is flexible in that derivatives of any order can be explicitly calculated such that controllers can be developed for models of any order. Using model-based feedforward control with the backward-difference method, accurate actuator control and stable RTHS are demonstrated using a nine-story steel building model implemented with an MR damper.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001938038
|
oai_dc
|
Analysis of decimation techniques to improve computational efficiency of a frequency-domain evaluation approach for real-time hybrid simulation
|
Analysis of decimation techniques to improve computational efficiency of a frequency-domain evaluation approach for real-time hybrid simulation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Tong Guo(Southeast University); Chengcheng(Southeast University); Weijie Xu(Southeast University)"
] |
Accurate actuator tracking is critical to achieve reliable real-time hybrid simulation results for earthquake engineering research. The frequency-domain evaluation approach provides an innovative way for more quantitative post-simulation evaluation of actuator tracking errors compared with existing time domain based techniques. Utilizing the Fast Fourier Transform the approach analyzes the actuator error in terms of amplitude and phrase errors. Existing application of the approach requires using the complete length of the experimental data. To improve the computational efficiency, two techniques including data decimation and frequency decimation are analyzed to reduce the amount of data involved in the frequency-domain evaluation. The presented study aims to enhance the computational efficiency of the approach in order to utilize it for future on-line actuator tracking evaluation. Both computational simulation and laboratory experimental results are analyzed and recommendations on the two decimation factors are provided based on the findings from this study.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001938044
|
oai_dc
|
Analysis of delay compensation in real-time dynamic hybrid testing with large integration time-step
|
Analysis of delay compensation in real-time dynamic hybrid testing with large integration time-step
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Fei Zhu(Tsinghua University); Jin-Ting Wang(Tsinghua University); Feng Jin(Tsinghua University); Yao Gui(Tsinghua University); Meng-Xia Zhou(Tsinghua University)"
] |
With the sub-stepping technique, the numerical analysis in real-time dynamic hybrid testing is split into the response analysis and signal generation tasks. Two target computers that operate in real-time may be assigned to implement these two tasks, respectively, for fully extending the simulation scale of the numerical substructure. In this case, the integration time-step of solving the dynamic response of the numerical substructure can be dozens of times bigger than the sampling time-step of the controller. The time delay between the real and desired feedback forces becomes more striking, which challenges the well-developed delay compensation methods in real-time dynamic hybrid testing. This paper focuses on displacement prediction and force correction for delay compensation in the real-time dynamic hybrid testing with a large integration time-step. A new displacement prediction scheme is proposed based on recently-developed explicit integration algorithms and compared with several commonly-used prediction procedures. The evaluation of its prediction accuracy is carried out theoretically, numerically and experimentally. Results indicate that the accuracy and effectiveness of the proposed prediction method are of significance.
|
토목공학
| null |
kci_detailed_000087.xml
|
|||
ART001938024
|
oai_dc
|
A novel hybrid testing approach for piping systems of industrial plants
|
A novel hybrid testing approach for piping systems of industrial plants
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Oreste S. Bursi(University of Trento); Giuseppe Abbiati(University of Trento); Md S. Reza(University of Trento)"
] |
The need for assessing dynamic response of typical industrial piping systems subjected to seismic loading motivated the authors to apply model reduction techniques to experimental dynamic substructuring. Initially, a better insight into the dynamic response of the emulated system was provided by means of the principal component analysis. The clear understanding of reduction basis requirements paved the way for the implementation of a number of model reduction techniques aimed at extending the applicability range of the hybrid testing technique beyond its traditional scope. Therefore, several hybrid simulations were performed on a typical full-scale industrial piping system endowed with a number of critical components, like elbows, Tee joints and bolted flange joints, ranging from operational to collapse limit states. Then, the favourable performance of the L-Stable Real-Time compatible time integrator and an effective delay compensation method were also checked throughout the testing campaign. Finally, several aspects of the piping performance were commented and conclusions drawn.
|
토목공학
| null |
kci_detailed_000088.xml
|
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