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ART001000805
|
oai_dc
|
Finite element vibration and damping analysis of a partially covered cantilever beam
|
Finite element vibration and damping analysis of a partially covered cantilever beam
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mustafa Yaman(Ataturk University)"
] |
There are several ways of decreasing the vibration energy of structures. One of which isspecial damping layers made of various viscoelastic materials are widely applied in structures subjected toinvestigated by using Finite Element method (FEM). The frequency and system loss factor are evaluated.The efects of diferent physical and geometrical parameters on the natural frequency and system lossfactors are discused.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001000806
|
oai_dc
|
The torsional buckling analysis for cylindrical shell with material non-homogeneity in thickness direction under impulsive loading
|
The torsional buckling analysis for cylindrical shell with material non-homogeneity in thickness direction under impulsive loading
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. H. Sofiyev(Suleyman Demirel University)"
] |
This study considers the buckling of orthotropic cylindrical thin shells with material non-homogeneity in the thickness direction, under torsion, which is a power function of time. The dynamictype variational method to these equations and taking the large values of loading parameters intoconsideration, analytic solutions are obtained for critical parameter values. Using those results, the effectsof the periodic and power variations of Youngs moduli and density, ratio of Youngs moduli variations,via pertinent computations. It is concluded that all these factors contribute to appreciable effects on thecritical parameters of the problem in question.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115346
|
oai_dc
|
Automatic modal identification and variability in measured modal vectors of a cable-stayed bridge
|
Automatic modal identification and variability in measured modal vectors of a cable-stayed bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y. Q. Ni(The Hong Kong Polytechnic University); K. Q. Fan(Wuyi University); G. Zheng(Chongqing Communications Research and Design Institute); J. M. Ko(The Hong Kong Polytechnic University)"
] |
An automatic modal identification program is developed for continuous extraction of modal parameters of three cable-supported bridges in Hong Kong which are instrumented with a long-term monitoring system. The program employs the Complex Modal Indication Function (CMIF) algorithm for identifying modal properties from continuous ambient vibration measurements in an on-line manner. By using the LabVIEW graphical programming language, the software realizes the algorithm in Virtual Instrument (VI) style. The applicability and implementation issues of the developed software are demonstrated by using one-year measurement data acquired from 67 channels of accelerometers permanently installed on the cable-stayed Ting Kau Bridge. With the continuously identified results, variability in modal vectors due to varying environmental conditions and measurement errors is observed. Such an observation is very helpful for selection of appropriate measured modal vectors for structural health monitoring use.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115391
|
oai_dc
|
An assumed-stress finite element for static and free vibration analysis of Reissner-Mindlin plates
|
An assumed-stress finite element for static and free vibration analysis of Reissner-Mindlin plates
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kutlu Darilmaz(Istanbul Technical University)"
] |
An assumed stress quadrilateral thin/moderately thick plate element HQP4 based on theMindlin/Reissner plate theory is proposed. The formulation is based on Hellinger-Reissner variationales are carried out. Numerical examples are presented toshow that the validity and efficiency of the present element for static and free vibration analysis of plates.Satisfactory accuracy for thin and moderately thick plates is obtained and it is free from shear locking forthin plate analysis.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001001751
|
oai_dc
|
Computation of structural intensity for plates with multiple cutouts
|
Computation of structural intensity for plates with multiple cutouts
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. S. Khun(National Univ. of Singapore); H. P. Lee(National Univ. of Singapore); S. P. Lim(National Univ. of Singapore)"
] |
The structural intensity fields of rectangular plates with single cutout and multiple cutouts arestudied. The main objective is to examine the effect of the presence of cutouts on the flow patern ofvibrational energy from the source to the sink on a rectangular plate. The computation of the structuralintensity is carried out using the finite element method. The magnitude of energy flow is significantlylarger at the edges on the plate near the cutout boundary parallel to the energy flow. The effects ofcutouts with diferent shape and size at diferent positions on structural intensity of a rectangular plate arepresented and discussed. A case study on a plate with two cutouts is also presented.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001001749
|
oai_dc
|
Stability of multi-step flexural-shear plates with varying cross-section
|
Stability of multi-step flexural-shear plates with varying cross-section
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"J. Y. Xu(Wuhan Univ. of Technology); Q. S. Li(City Univ. of Hong Kong)"
] |
In this paper, multi-story buildings with shear-wal structures and with narrow rectangularplane configuration are modeled as a multi-step flexural-shear plate with varying cross-section forbuckling analysis. The governing diferential equation of such a plate is established. Using appropriatetransformations, the equation is reduced to analyticaly solvable equations by selecting suitable expresionsof the distribution of stifnes. The exact solutions for buckling of such a one-step flexural-shear platewith variable stifnes are derived for several cases. A new exact approach that combines the transfermatrix method and closed from solution of one-step flexural-shear plate with continuously varyingstifnes is presented for stability analysis of multi-step non-uniform flexural-shear plate. A numericalexample shows that the present methods are easy to implement and efficient.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001001750
|
oai_dc
|
Lateral buckling of beams with top bracing
|
Lateral buckling of beams with top bracing
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jong Sup Park(Auburn Univ.); 강영종(Korea Univ.)"
] |
This paper presents the lateral-torsional buckling (LTB) of beams or girders with continuouslateral support at top flange. Traditional moment gradient factors (Cb) given by AISC in LRFDSpecification for Structural Stel Buildings and by AASHTO in LRFD Bridge Design Specifications werereviewed. Finite-element method buckling analyses of doubly symetric I-shaped beams with continuoustop bracing were conducted to develop new moment gradient factors. A uniformly distributed load wasapplied at midheight and either or both end moments were applied at the ends of beams. The proposedsolutions are simple and acurate for use by engineers to determine the LTB resistance of beams.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001001746
|
oai_dc
|
On complex flutter and buckling analysis of a beam structure subjected to static follower force
|
On complex flutter and buckling analysis of a beam structure subjected to static follower force
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Q. Wang(Univ. of Central Florida)"
] |
The fluter and buckling analysis of a beam structure subjected to a static follower force iscompletely studied in the paper. The beam is fixed in the transverse direction and constrained by arotational spring at one end, and by a translational spring and a rotational spring at the other end. The co-existence of flutter and buckling in this beam due to the presence of the follower force is an interesting andimportant phenomenon. The results from this theoretical analysis wil be useful for the stability design ofstructures in enginering applications, such as the potential of flutter control of aircrafts by smart materials.The transition-curve surface for diferentiating the two distinct instability regions of the beam is firstobtained with respect to the variations of the stiffness of the springs at the two ends. Second, the capacityof the folower force is derived for flutter and buckling of the beam as a function of the stiffnes of thesprings by observing the variation of the first two frequencies obtained from dynamic analysis of the beam.The research in the paper may be used as a benchmark for the fluter and buckling analysis of beams.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001001747
|
oai_dc
|
Optimal lay-up of hybrid composite beams, plates and shells using cellular genetic algorithm
|
Optimal lay-up of hybrid composite beams, plates and shells using cellular genetic algorithm
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S. Rajasekaran(PSG College of Technology); K. Nalinaa(PSG College of Technology); S. Greeshma(PSG College of Technology); N.S. Poornima(PSG College of Technology); V. Vinoop Kumar(PSG College of Technology)"
] |
Laminated composite structures find wide range of applications in many branches oftechnology. They are much suited for weight sensitive structures (like aircraft) where thinner and lightermembers made of advanced fiber reinforced composite materials are used. The orientations of fiberdirection in layers and number of layers and the thicknes of the layers as wel as material of compositesplay a major role in determining the strength and stifnes. Thus the basic design problem is to determinethe optimum stacking sequence in terms of laminate thicknes, material and fiber orientation. In thispaper, a new optimization technique caled Celular Automata (CA) has ben combined with GeneticAlgorithm (GA) to develop a diferent search and optimization algorithm, known as Celular GeneticAlgorithm (CGA), which considers the laminate thicknes, angle of fiber orientation and the fiber materialas discrete variables. This CGA has ben sucesfully applied to obtain the optimal fiber orientation,thicknes and material lay-up for multi-layered composite hybrid beams plates and shels subjected tostatic buckling and dynamic constraints.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001001745
|
oai_dc
|
Design of ＂Smart＂ flap actuators for swept shock wave/turbulent boundary layer interaction control
|
Design of ＂Smart＂ flap actuators for swept shock wave/turbulent boundary layer interaction control
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jonathan Couldrick(Univ. College); Krishnakumar Shankar(Univ. College); Sudhir Gai(Univ. College); John Milthorpe(Univ. College)"
] |
Piezoelectric actuators have long been recognised for use in aerospace structures for controlof structural shape. This paper looks at active control of the swept shock wave/turbulent boundary layerinteraction using smart flap actuators. The actuators are manufactured by bonding piezoelectric material toan inert substrate to control the bled/suction rate through a plenum chamber. The cavity providescomunication of signals acros the shock, alowing rapid thickening of the boundary layer approachingthe shock, which splits into a series of weaker shocks forming a lambda shock foot, reducing wave drag.Active control alows optimum control of the interaction, as it would be capable of positioning the controlregion around the original shock position and unimorph tip deflection, hence mas transfer rates. Theactuators are modeled using classical composite material mechanics theory, as well as a finite element-modeling program (ANSYS 5.7).
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001001748
|
oai_dc
|
A two-step approach for joint damage diagnosis of framed structures using artificial neural networks
|
A two-step approach for joint damage diagnosis of framed structures using artificial neural networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"W. L. Qu(Wuhan Univ. of Technology); W. Chen(Wuhan Univ. of Technology); Y.Q. Xiao(City Univ. of Hong Kong)"
] |
Since the conventional direct aproaches are hard to be aplied for damage diagnosis ofcomplex large-scale structures, a two-step approach for diagnosing the joint damage of framed structures ispresented in this paper by using artificial neural networks. The first step is to judge the damaged areas of astructure, which is divided into several sub-areas, using probabilistic neural networks with naturalFrequencies Shift Ratio inputs. The next step is to diagnose the exact damage locations and extents by usingthe Radial Basis Function (RBF) neural network with the second Element End Strain Mode of the damagedsub-area input. The results of numerical simulation show that the proposed approach could diagnose the jointdamage of framed structures induced by earthquake action effectively and has reliable anti-jamming abilities.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115387
|
oai_dc
|
Develoment of a meshless finite mixture(MFM) method
|
Develoment of a meshless finite mixture(MFM) method
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"J. Q. Cheng(Inst. of High Performance Comput); H. P. Lee(Inst. of High Performance Comput); Hua Li(Inst. of High Performance Comput)"
] |
A meshless method with novel variation of point collocation by finite mixture approximationis developed in this paper, termed the meshless finite mixture (MFM) method. It is based on the finitemixture theorem and consists of two or more existing meshless techniques for exploitation of theirrespective merits for the numerical solution of partial differential boundary value (PDBV) problems. Inthis representation, the classical reproducing kernel particle and diferential quadrature techniques aremixed in a point collocation framework. The least-square method is used to optimize the value of theweight coefficient to construct the final finite mixture approximation with higher accuracy and numericalstability. In order to validate the developed MFM method, several one- and two-dimensional PDBVproblems are studied with different mixed boundary conditions. From the numerical results, it is observedthat the optimized MFM weight coefficient can improve significantly the numerical stability and accuracyof the newly developed MFM method for the various PDBV problems.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115342
|
oai_dc
|
Short-term cyclic performance of metal-plate-connected wood truss joints
|
Short-term cyclic performance of metal-plate-connected wood truss joints
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rakesh Gupta(Oregon State University); Thomas H. Miller(Oregon State University); S.M.W. Freilinger(Oregon Dept. of Transportation)"
] |
The objective of this research was to evaluate the performance of metal-plate-connected trussjoints subjected to cyclic loading conditions that simulated seismic events in the lives of the joints. Wealso investigated the duration of load factor for these joints. We tested tension splice joints and heel jointsfrom a standard 9.2-m Fink truss constructed from 38- 89-mm Douglas-fir lumber: 10 tension splicejoints for static condition and for each of 6 cyclic loading conditions (70 joints total) and 10 heel jointsfor static condition and for each of 3 cyclic loading conditions (40 joints total). We evaluated results bycomparing the strengths of the control group (static) with those of the cyclic loading groups. None of thecyclic loading conditions showed any strength degradation; however, there was significant stiffnessdegradation for both types of joint. The results of this research show that the current duration of loadfactor of 1.6 for earthquake loading is adequate for these joints.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000947966
|
oai_dc
|
Evaluation of shear lag parameters for beam-to-column connections in steel piers
|
Evaluation of shear lag parameters for beam-to-column connections in steel piers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Won-Sup Hwang(Inha University); Young-Pil Kim(Inha University); Yong-Myung Park(Pusan Nat. University)"
] |
The paper presents shear lag parameters for beam-to-column connections in steel box piers.Previous researches have analyzed beam-to-column connections in steel piers using a shear lag parameterho obtained from a simple beam model, which is not based on a reasonable design assumption. Instead,the current paper proposes a cantilever beam model and has proved the effectiveness through theoreticaland experimental studies. The paper examines the inaccuracy of the previous researches by estimating theeffective width, the width-span length ratio L/b, and the sectional area ratio S of a cantilever beam. Twodiferent shear lag parameters are defined using the cantilever model and the results are compared eachother. The first type of shear lag parameter hc of a cantilever beam is derived using additional momentsfrom various stres distribution functions while the other shear lag parameter heff of a cantilever beam isdefined based on the concept of the effective width. An evaluation method for shear lag stresses has beeninvestigated by comparing analytical streses with test results. Through the study, it could be observedthat the shear lag parameter heff agrees with hc obtained from the 2nd order stres distribution function.Also, it could be observed that the shear lag parameter hc using the 4th order stres distribution functionalmost converges to the upper bound of test results.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115389
|
oai_dc
|
Dynamic of thick hygrouthermal viscoelastic composite laminates through finite element method
|
Dynamic of thick hygrouthermal viscoelastic composite laminates through finite element method
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Amr E. Assie(Zagazig University); Fatin F. Mahmoud(Zagazig University)"
] |
An uncoupled computational model for analyzing the hygrothermal dynamic response ofcomposite laminates has been developed. The constitutive equations, expressed in an integral form, andinvolving relaxation moduli are adopted, to describe the non-aging hygrothermorheologically simplematerials. A Prony series represents the relaxation moduli is exploited in order to derive a recursiverelationship, and thereby eliminate the storage problem that arises when dealing with material possessingmemory. The problem is formulated in a descritized variational form. Mindlin and higher order finiteelements are employed for spatial descretization, while the Newmark average acceleration scheme isexploited for temporal descritization. The adopted recursive formula uses only the details of the previousevent to compute the details of the current one. Numerical results of the displacement fields of both thinand thick viscoelastic laminates problems are discussed to show up the effectiveness of Mindlin andhigher-order shear theories.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115344
|
oai_dc
|
Evaluation of typhoon induced fatigue damage using health monitoring data for the Tsing Ma Bridge
|
Evaluation of typhoon induced fatigue damage using health monitoring data for the Tsing Ma Bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Tommy H. T. Chan(The Hong Kong Polytech Univ); Z. X. Li(Southeast University); J. M. Ko(The Hong Kong Polytech Univ)"
] |
This paper aims to evaluate the effect of typhoons on fatigue damage accumulation in steel
decks of long-span suspension bridges. The strain-time histories at critical locations of deck sections of
long-span bridges during different typhoons passing the bridge area are investigated by using on-line
strain data acquired from the structural health monitoring system installed on the bridge. The fatigue
damage models based on Miner’s Law and Continuum Damage Mechanics (CDM) are applied to
calculate the increment of fatigue damage due to the action of a typhoon. Accumulated fatigue damage
during the typhoon is also calculated and compared between Miner’s Law and the CDM method. It is
found that for the Tsing Ma Bridge case, the stress spectrum generated by a typhoon is significantly
different than that generated by normal traffic and its histogram shapes can be described approximately as
a Rayleigh distribution. The influence of typhoon loading on accumulative fatigue damage is more
significant than that due to normal traffic loading. The increment of fatigue damage generated by hourly
stress spectrum for the maximum typhoon loading may be much greater than those for normal traffic
loading. It is, therefore, concluded that it is necessary to evaluate typhoon induced fatigue damage for the
purpose of accurately evaluating accumulative fatigue damage for long-span bridges located within
typhoon prone regions.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115343
|
oai_dc
|
An analytical solution for static analysis of a simply supported moderately thick sandwich piezoelectric plate
|
An analytical solution for static analysis of a simply supported moderately thick sandwich piezoelectric plate
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lanhe Wu(Shijiazhuang Railway Inst.); Zhiqing Jiang(Shijiazhuang Railway Inst.); Wenjie Feng(Shijiazhuang Railway Inst.)"
] |
This paper presents a theoretic model of a smart structure, a transversely isotropicpiezoelectric thick square plate constructed with three laminas, piezoelectric-elastic-piezoelectric layer, byadopting the first order shear deformation plate theory and piezoelectric theory. This model assumes thatthe transverse displacements through thickness are linear, and the in-plane displacements in the mid-planeof the plate are not taken to be account. By using Fouriers series expansion, an exact Navier typedanalytical solution for deflection and electric potential of the simply supported smart plate is obtained.The electric boundary conditions are being grounded along four vertical edges. The external voltage andnon-external voltage applied on the surfaces of piezoelectric layers are all considered. The convergence ofthe present approach is carefully studied. Comparison studies are also made for verifying the accuracy andthe applicability of the present method. Then some new results of the electric potentials and displacementsare provided. Numerical results show that the electrostatic voltage is approximately linear in the thicknessdirection, while parabolic in the plate in-plane directions, for both the deflection and the electric voltage.These results are very useful for distributed sensing and finite element verification.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115341
|
oai_dc
|
Local zooming genetic altorithm and its application to radial gate support problems
|
Local zooming genetic altorithm and its application to radial gate support problems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Young-Doo Kwon(Kyungpook University); Seung-Bo Jin(Korea Aerospace Res. Inst.); Jae-Yong Kim(Korea Atomic Res. Inst.); Il-Hee Lee(Vith Turbo Co.)"
] |
On the basis of a structural analysis of radial gate (i.e. Tainter gate), the current paperfocuses on weight minimization according to the location of the arms on a radial gate. In spite of itseconomical significance, there are hardly any previous studies on the optimum design of radial gate.Accordingly, the present study identifies the optimum position of the support point for a radial gate thatguarantees the minimum weight satisfying the strength constraint conditions. This study also identifies theoptimum position for 2 or 3 radial arms with a convex cylindrical skin plate relative to a given radius ofthe skin plate curvature, pivot point, water depth, ice pressure, etc. These optimum designs are thencompared with previously constructed radial gates. Local genetic and hybrid-type genetic algorithms areused as the optimum tools to reduce the computing time and enhance the accuracy. The results indicatethat the weights of the optimized radial gates are appreciably lower than those of previously constructedgates.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115388
|
oai_dc
|
Optimal design using genetic altorithm with nonlinear elastic analysis
|
Optimal design using genetic altorithm with nonlinear elastic analysis
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김승억(세종대학교); W. K. Song(Korea Infra. Safety and Tech.); S.S. Ma(KTH Mechanics)"
] |
An optimal design method with nonlinear elastic analysis is presented. The proposednonlinear elastic method overcomes the drawback of the conventional LRFD method that accounts fornonlinear effect by using the moment amplification factors of B1 and B2. The genetic algorithm used is aprocedure based on Darwinian notions of survival of the fittest, where selection, crossover, and mutationoperators are employed to look for high performance ones among sections in the database. They aresatisfied with the constraint functions and give the lightest weight to the structure. The objective functiontaken is the total weight of the steel structure and the constraint functions are strength, serviceability, andductility requirement. Case studies of a planar portal frame, a space two-story frame, and a three-dimensional steel arch bridge are presented.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115252
|
oai_dc
|
Design and performance validation of a wireless sensing unit for structural monitoring applications
|
Design and performance validation of a wireless sensing unit for structural monitoring applications
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jerome P. Lynch(Univ. of Michigan); K. H. Law(Stanford Univ.); A. S. Kiremidjian(Stanford Univ.); Ed Carryer(Stanford Univ.); C. R. Farrar(Los Alamos Lab.); 손훈(Los Alamos Lab.); D. W. Allen(Los Alamos Lab.); B. Nadler(Los Alamos Lab.); J. R. Wait(Los Alamos Lab.)"
] |
There exists a clear need to monitor the performance of civil structures over their operational
lives. Current commercial monitoring systems suffer from various technological and economic limitations
that prevent their widespread adoption. The wires used to route measurements from system sensors to the
centralized data server represent one of the greatest limitations since they are physically vulnerable and
expensive from an installation and maintenance standpoint. In lieu of cables, the introduction of low-cost
wireless communications is proposed. The result is the design of a prototype wireless sensing unit that
can serve as the fundamental building block of wireless modular monitoring systems (WiMMS). An
additional feature of the wireless sensing unit is the incorporation of computational power in the form of
state-of-art microcontrollers. The prototype unit is validated with a series of laboratory and field tests. The
Alamosa Canyon Bridge is employed to serve as a full-scale benchmark structure to validate the
performance of the wireless sensing unit in the field. A traditional cable-based monitoring system is
installed in parallel with the wireless sensing units for performance comparison.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000947568
|
oai_dc
|
Dynamic analysis of structure/foundation systems
|
Dynamic analysis of structure/foundation systems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Joseph Penzien(Int. Civ. Eng. Consultant Inc.)"
] |
A review of current procedures being used in engineering practice to analyze the response ofstructure/foundation systems subjected separately to diferent types of dynamic excitation, such asearthquake, sea-wave action, wind, or moving wheel loads, is presented. Separate formulations are givenfor analyzing systems in the time and frequency domains. Both deterministic and stochastic forms ofexcitation are treated. A distinction is made between demand and capacity analyses.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000948261
|
oai_dc
|
State-of-the-art of semiactive control systems using MR fluid dampers in civil engineering applications
|
State-of-the-art of semiactive control systems using MR fluid dampers in civil engineering applications
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"정형조(세종대학교); B. F. Spencer Jr.(Univ. of Illinoise); Y. Q. Ni(Hong Kong Polytech. Univ.); I.-W. Lee(KAIST)"
] |
Semiactive control systems have received considerable attention for protecting structuresagainst natural hazards such as strong earthquakes and high winds, because they not only offer thereliability of passive control systems but also maintain the versatility and adaptability of fully activecontrol systems. Among the many semiactive control devices, magnetorheological (MR) fluid damperscomprise one particularly promising class. In the field of civil engineering, much research anddevelopment on MR fluid damper-based control systems has been conducted since this unique semiactivedevice was first introduced to civil engineering applications in mid 1990s. In 2001, MR fluid damperswere applied to the full-scale in-service civil engineering structures for the first time. This state-of-the-artpaper includes a detailed literature review of dynamic models of MR fluid dampers for describing theircomplex dynamic behavior and control algorithms considering the characteristics of MR fluid dampers.This extensive review provides references to semiactive control systems using MR fluid dampers. TheMR fluid damper-based semiactive control systems are shown to have the potential for mitigating theresponses of ful-scale civil engineering structures under natural hazards.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115251
|
oai_dc
|
Adaptive mesh refinement/recovery strategy for FEA
|
Adaptive mesh refinement/recovery strategy for FEA
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chang-Koon Choi(KAIST); Eun-Jin Lee(KAIST); Won-Jin Yu(Samsung Eng. & Constr.)"
] |
This paper deals with the development of h-version adaptive mesh refinement and recoverystrategy using variable-node elements and its application to various engineering field problems with 2Dquadrilateral and 3D hexahedral models. The variable-node elements which have variable mid-side nodeson edges or faces are effectively used in overcoming some problems in connecting the different layerpatterns of the transition zone between the refined and coarse mesh. A modified recovery technique ofgradients adequate for variable-node elements and proper selection of error norms for each engineeringfield problems are proposed. In the region in which the eror is greater than the permissible refinementerror, the mesh is locally refined by subdivision. Reversely, in some parts of the domain having the errorsmaller than the permissible recovery eror, the mesh is locally recovered (coarsened) by combination.Hierarchical structures (e.g. quadtrees and octrees) and element-based storage structures are composed toperform this adaptive process of refinement and recovery. Some numerical examples of a 3D heatconduction analysis of the concrete with hydration heat and a 2D flow analysis of vortex shedding showeffectiveness and validity of the proposed scheme.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115298
|
oai_dc
|
Identification of prestress-loss in PSC beams using modal information
|
Identification of prestress-loss in PSC beams using modal information
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김정태(한국과학기술원); 윤정방(한국과학기술원); Y. S. Ryu(Pukyong National University); 조현만(부경대학교)"
] |
One of the uncertain damage parameters to jeopardize the safety of existing PSC bridges isthe loss of the prestress force. A substantial prestress-loss can lead to severe problems in the serviceabilityand safety of the PSC bridges. In this paper, a nondestructive method to detect prestress-los in beam-typePSC bridges using a few natural frequencies is presented. An analytical model is formulated to estimatechanges in natural frequencies of the PSC bridges under various prestress forces. Also, an inverse-solutionalgorithm is proposed to detect the prestres-loss by measuring the changes in natural frequencies. Thefeasibility of the proposed approach is evaluated using PSC beams for which a few natural frequencieswere experimentally measured for a set of prestress-loss cases. Numerical models of two-span continuousPSC beams are also examined to verify that the proposed algorithm works on more complicated cases.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115299
|
oai_dc
|
Fragility reduction using passive response modification in a Consequence-Based Engineering(CBE) framework
|
Fragility reduction using passive response modification in a Consequence-Based Engineering(CBE) framework
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"L. Duenas-Osorio(Georgia Inst. of Tech.); 박주남(Georgia Inst. of Tech.); P. Towashiraporn(Georgia Inst. of Tech.); B. J. Goodno(Georgia Inst. of Tech.); D. Frost(Georgia Inst. of Tech.); J. I. Craig(Georgia Inst. of Tech.); Ann Bostrom(Georgia Inst. of Tech.)"
] |
Consequence-Based Engineering (CBE) is a new paradigm proposed by the Mid-AmericaEarthquake Center (MAE) to guide evaluation and rehabilitation of building structures and networks inareas of low probability - high consequence earthquakes such as the central region of the U.S. Theprincipal objective of CBE is to minimize consequences by prescribing appropriate intervention proceduresfor a broad range of structures and systems, in consultation with key decision makers. One possibleintervention option for rehabilitating unreinforced masonry (URM) buildings, widely used for essentialfacilities in Mid-America, is pasive energy disipation (PED). After the CBE process is described, itsapplication in the rehabilitation of vulnerable URM building construction in Mid-America is illustratedthrough the use of PED devices attached to flexible timber floor diaphragms. It is shown that PEDs canbe applied to URM buildings in situations where flor diaphragm flexibility can be controlled to reduceboth out-of-plane and in-plane wall responses and damage. Reductions as high as 48% in rofdisplacement and acceleration can be achieved as demonstrated in studies reported below.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115300
|
oai_dc
|
Controller optimization with constraints on probabilistic peak responses
|
Controller optimization with constraints on probabilistic peak responses
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"박지훈(MIDASIT Co., Ltd.); 민경원(단국대학교); 박홍근(서울대학교)"
] |
Peak response is a more suitable index than mean response in the light of structural safety. Inthis study, a controller optimization method is proposed to restrict peak responses of building structuressubject to earthquake excitations, which are modeled as partially stationary stochastic process. Theconstraints are given with specified failure probabilities of peak responses. LQR is chosen to assurestability in numerical process of optimization. Optimization problem is formulated with weightings oncontroled outputs as design variables and gradients of objective and constraint functions are derived. Fullstate feedback controllers designed by the proposed method satisfy various design objectives and outputfeedback controllers using LQG also yield similar results without significant performance deterioration.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000948263
|
oai_dc
|
On magnetostrictive materials and their use in adaptive structures
|
On magnetostrictive materials and their use in adaptive structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Marcelo J. Dapino(The Ohio State University)"
] |
Magnetostrictive materials are routinely employed as actuator and sensor elements in a widevariety of noise and vibration control problems. In infrastructural applications, other technologies such ashydraulic actuation, piezoelectric materials and more recently, magnetorheological fluids, are being favoredfor actuation and sensing purposes. These technologies have reached a degree of technical maturity and insome cases, cost effectiveness, which justify their broad use in infrastructural applications. Advanced civilstructures present new challenges in the areas of condition monitoring and repair, reliability, and high-authority actuation which motivate the need to explore new methods and materials recently developed inthe areas of materials science and transducer design. This paper provides an overview of a class ofmaterials that because of the large force, displacement, and energy conversion effciency that it canprovide is being considered in a growing number of quasistatic and dynamic applications. Sincemagnetostriction involves a bidirectional energy exchange between magnetic and elastic states,magnetostrictive materials provide mechanisms both for actuation and sensing. This paper provides anoverview of materials, methods and applications with the goal to inspire novel solutions based onmagnetostrictive materials for the design and control of advanced infrastructural systems.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000948264
|
oai_dc
|
Nonlinear dynamic analysis of RC frames using cyclic moment-curvature relation
|
Nonlinear dynamic analysis of RC frames using cyclic moment-curvature relation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"곽효경(KAIST); Sun-Pil Kim(KAIST); Ji-Eun Kim(KAIST)"
] |
Nonlinear dynamic analysis of a reinforced concrete (RC) frame under earthquake loading is
performed in this paper on the basis of a hysteretic moment-curvature relation. Unlike previous analytical moment-curvature relations which take into account the flexural deformation only with the perfect-bond assumption, by introducing an equivalent flexural stiffness, the proposed relation considers the rigid-bodymotion due to anchorage slip at the fixed end, which accounts for more than 50% of the total deformation. The advantage of the proposed relation, compared with both the layered section approach and the multi-component model, may be the ease of its application to a complex structure composed of many elements and on the reduction in calculation time and memory space. Describing the structural response more exactly becomes possible through the use of curved unloading and reloading branches inferred from the stress-strain relation of steel and consideration of the pinching effect caused by axial force. Finally, the applicability of the proposed model to the nonlinear dynamic analysis of RC structures
is established through correlation studies between analytical and experimental results.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000947653
|
oai_dc
|
Decentralized energy market-based structural control
|
Decentralized energy market-based structural control
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"J. P. Lynch(Univ. of Michigan); K. H. Law(Stanford Univ.)"
] |
Control systems are used to limit structural lateral deflections during large external loadssuch as winds and earthquakes. Most recently, the semi-active control approach has grown in popularitydue to inexpensive control devices that consume little power. As a result, recently designed controlsystems have employed many semi-active control devices for the control of a structure. In the future, it isenvisioned that structural control systems will be large-scale systems defined by high actuation and sensordensities. Decentralized control approaches have been used to control large-scale systems that are toocomplex for a traditional centralized approach, such as linear quadratic regulation (LQR). This paperdescribes the derivation of energy market-based control (EMBC), a decentralized approach that models thestructural control system as a competitive marketplace. The interaction of free-market buyers and sellersresult in an optimal allocation of limited control system resources such as control energy. The Kajima-Shizuoka Building and a 20-story benchmark structure are selected as illustrative examples to be used forcomparison of the EMBC and centralized LQR approaches.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000947569
|
oai_dc
|
Damage index sensor for smart structures
|
Damage index sensor for smart structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Akira Mita(Keio University); Shinpei Takahira(Keio University)"
] |
A new sensor system is proposed for measuring damage indexes. The damage index is aphysical value that is well corelated to a critical damage in a device or a structure. The mechanismproposed here utilizes elastic buckling of a thin wire and does not require any external power supply formemorizing the index. The mechanisms to detect peak strain, peak displacement, peak acceleration andcumulative deformation as examples of damage indexes are presented. Furthermore, passive and activewireless data retrieval mechanisms using electromagnetic induction are proposed. The passive wirelesssystem is achieved by forming a closed LC circuit to oscillate at its natural frequency. The active wirelesssensor can transmit the data much further than the pasive system at the sacrifice of slightly complicatedelectric circuit for the sensor. For wireless data retrieval, no wire is needed for the sensor to supplyelectrical power. For the active system, electrical power is supplied to the sensor by radio waves emittedfrom the retrieval system. Thus, external power supply is only needed for the retrieval system when theretrieval becomes necesary. Theoretical and experimental studies to show excellent performance of theproposed sensor are presented. Finally, a prototype damage index sensor installed into a 7 storey base-isolated building is explained.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000947597
|
oai_dc
|
Intelligent hybrid controlled structures with soil-structure interaction
|
Intelligent hybrid controlled structures with soil-structure interaction
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"X.Z. Zhang(University of Missouri-Rolla); Franklin Y. Cheng(University of Missouri-Rolla); M. L. Lou(Tongji University)"
] |
A hybrid control system is presented for seismic-resistant building structures with andwithout soil-structure interaction (SI). The hybrid control is a damper-actuator-bracing control systemcomposed of passive and active controllers. An intelligent algorithm is developed for the hybrid system,in which the passive damper is designed for minor and moderate earthquakes and the active control isdesigned to activate when the structural response is greater than a given threshold quantity. Thus, theexternal energy for active controller can be optimally utilized. In the control of a multistory building, thecontroler placement is determined by evaluating the optimal location index (OLI) calculated from sixearthquake sources. In the study, the soil-structure interaction is considered both in frequency domain andtime domain analyses. It is found that the interaction can significantly affect the control effectiveness. Inthe hybrid control algorithm with intelligent strategy, the working stages of passive and active controllerscan be diferent for a building with and without considering SSI. Thus SSI is essential to be included inpredicting the response history of a controled structure.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000948260
|
oai_dc
|
Damage assessment of cable stayed bridge using probabilistic neural network
|
Damage assessment of cable stayed bridge using probabilistic neural network
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hyo-Nam Cho(Hanyang University); Y. M. Choi(Hanyang University); Sung-Chil Lee(Hanyang University); Choon-Kun Hur(Hanyang University)"
] |
This paper presents an efficient algorithm for the estimation of damage location and severityin bridge structures using Probabilistic Neural Network (PN). Generally, the Back Propagation NeuralNetwork (BPN)-based damage detection methods need a lot of training patterns for neural networklearning process and the optimum architecture of a BPN is selected by trial and eror. In this paper, thePN instead of the conventional BPN is used as a pattern classifier. The modal properties of damagedstructure are somewhat diferent from those of undamaged one. The basic idea of proposed algorithm isthat the PN classifies a test pattern which consists of the modal characteristics from damaged structure,how close it is to each training pattern which is composed of the modal characteristics from variousstructural damage cases. In this algorithm, two PNs are sequentially used. The first PNN estimates thedamage location using mode shape and the results of the first PN are put into the second PN for thedamage severity estimation using natural frequency. The proposed damage assesment algorithm using thePN is applied to a cable-stayed bridge to verify its applicability.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000947570
|
oai_dc
|
Fiber optic smart monitoring of concrete beam retrofitted by composite patches
|
Fiber optic smart monitoring of concrete beam retrofitted by composite patches
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ki-Soo Kim(Hoseo University); Chul Chung(Hoseo University); Ho-Joon Lee(Hoseo University); Young-Goo Kang(Hoseo University); Hong Kim(Hoseo University)"
] |
In order to extend the lifetime of buildings and civil infrastructure, patch type fibrouscomposite retrofitting materials are widely used. Retrofitted concrete columns and beams gain stiffnessand strength, but lose toughness and show brittle failure. Usually, the cracks in concrete structures arevisible to the naked eye and the status of the structure in the life cycle is estimated through visualinspections. After retrofitting of the structure, crack visibility is blocked by retrofitted composite materials.Therefore, structural monitoring after retrofitting is indispensable and self diagnosis method with opticalfiber sensors is very useful. In this paper, we try to detect the peel out effect and find the strain diferencebetween the main structure and retrofitting patch material when they separate from each other. In theexperiment, two fiber optic Bragg grating sensors are applied to the main concrete structure and thepatching material separately at the same position. The sensors show coincident behaviors at the initialloading, but different behaviors after a certain load. The test results show the posibility of optical fibersensor monitoring of beam structures retrofitted by the composite patches.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115253
|
oai_dc
|
Holder exponent analysis for discontinuity detection
|
Holder exponent analysis for discontinuity detection
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"손훈(Los Alamos Lab.); A. N. Robertson(Los Alamos Lab.); C. R. Farrar(Los Alamos Lab.)"
] |
In this paper, a Holder exponent, a measure of the degree to which a signal is differentiable,is presented to detect the presence of a discontinuity and when the discontinuity occurs in a dynamicsignal. This discontinuity detection has potential applications to structural health monitoring becausediscontinuities are often introduced into dynamic response data as a result of certain types of damage.Wavelet transforms are incorporated with the Holder exponent to capture the time varying nature ofdiscontinuities, and a classification procedure is developed to quantify when changes in the Holderexponent are significant. The proposed Holder exponent analysis is applied to various experimental signalsto reveal underlying damage causing events from the signals. Signals being analyzed include accelerationresponse of a mechanical system with a rattling internal part, acceleration signals of a three-story buildingmodel with a loosing bolt, and strain records of an in-situ bridge during construction. The experimentalresults presented in this paper demonstrate that the Holder exponent can be an effective tool foridentifying certain types of events that introduce discontinuities into the measured dynamic response data.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000947596
|
oai_dc
|
Piezoelectric friction dampers ofr earthquake mitigation of buildings: design, fabrication and characterization
|
Piezoelectric friction dampers ofr earthquake mitigation of buildings: design, fabrication and characterization
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Genda Chen(University of Missouri-Rolla); G. T. Garrett(University of Missouri-Rolla); C.Q. Chen(University of Missouri-Rolla); Franklin Y. Cheng(University of Missouri-Rolla)"
] |
In this paper, the design, fabrication and characterization of a piezoelectric friction damperare presented. It was sized with the proposed practical procedure to minimize the story drift and flooracceleration of an existing 1/4-scale, three-story frame structure under both near-fault and far-fieldearthquakes. The design operation friction force in kip was numerically determined to range from 2.2 to3.3 times the value of the peak ground acceleration in g (gravitational acceleration). Experimental resultsindicated that the load-displacement loop of the damper is nearly rectangular in shape and independent ofthe excitation frequency. The coefficient of friction of the damper is approximately 0.85 when theclamping force on the damper is above 400 lbs. It was found that the friction force variation of thedamper generated by piezoelectric actuators with 1000 Volts is approximately 90% of the expected value.The properties of the damper are insensitive to its ambient temperature and remain almost the same afterbeing tested for more than 12,000 cycles.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000948262
|
oai_dc
|
The utilities of U-shape EM sensor in stress monitoring
|
The utilities of U-shape EM sensor in stress monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"G. Wang(The Univ. of Illinois); M. L. Wang(The Univ. of Illinois)"
] |
In this paper, load monitoring technologies using U-shape Magnetoelastic (EM or ME)sensors have been exploited systemically for the first time. The steel rod to be tested is the Japan 7 mpiano steel rod. The load dependence of the magnetic properties of the piano steel rod was manifested.Two experimental designs of U-shape magnetoelastic sensors were introduced, one with double pick-upconcentric coils wound on the rod to be tested, the other with pick-up coil on one yoke fot. The formerdesign is used to derive the correlation of the relative permeability with elastic tension, while the latter isaimed to reflect the stress induced magnetic flux variation along the magnetic circuit. Magnetostaticsimulations provide interpretations for the yoke fot sensing technology. Tests with double pick-up coilsindicate that under proper working points (primary voltages), the relative permeability varies linearly withthe axial load for the Japan 7 mm piano steel rod. Tests with pick-up coil on the yoke foot show that theintegrated sensing voltage changes quadratically with the load, and error is more acceptable when theworking point is high enough.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001464231
|
oai_dc
|
Output-only modal parameter identification of civil engineering structures
|
Output-only modal parameter identification of civil engineering structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wei-Xin Ren(Fuzhou University); Zhou-Hong Zong(Fuzhou University)"
] |
The ambient vibration measurement is a kind of output data-only dynamic testing where the traffics and winds are used as agents responsible for natural or environmental excitation. Therefore an experimental modal analysis procedure for ambient vibration testing will need to base itself on output-only
data. The modal analysis involving output-only measurements presents a challenge that requires the use of special modal identification technique, which can deal with very small magnitude of ambient vibration contaminated by noise. Two complementary modal analysis methods are implemented. They are rather simple peak picking (PP) method in frequency domain and more advanced stochastic subspace identification (SSI) method in time domain. This paper presents the application of ambient vibration testing and experimental modal analysis on large civil engineering structures. A 15 storey reinforced concrete shear core building and a concrete filled steel tubular arch bridge have been chosen as two case studies. The results have shown that both techniques can identify the frequencies effectively. The stochastic subspace identification technique can detect frequencies that may possibly be missed by the peak picking method and gives a more reasonable mode shapes in most cases.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115297
|
oai_dc
|
Comparative study on modal identification methods using output-only information
|
Comparative study on modal identification methods using output-only information
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jin-Hak Yi(KAIST); 윤정방(한국과학기술원)"
] |
In this paper, several modal identification techniques for output-only structural systems areextensively investigated. The methods considered are the power spectral method, the frequency domaindecomposition method, the Ibrahim time domain method, the eigensystem realization algorithm, and thestochastic subspace identification method. Generally, the power spectral method is most widely used inpractical area, however, the other methods may give better estimates particularly for the cases with closedmodes and/or with large measurement noise. Example analyses were carried out on typical structuralsystems under three different loading cases, and the identification performances were examined throughtthe comparisons between the estimates by various methods.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115201
|
oai_dc
|
Design load-carrying capacity estimates and an improved wooden shore setup
|
Design load-carrying capacity estimates and an improved wooden shore setup
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y. L. Huang(Chung Hsing Univ.); Y. C. Lin(Chung Hsing Univ.); C. F. Lee(Chung Hsing Univ.); H. J. Chen(Chung Hsing Univ.); T. Yen(Chung Hsing Univ.)"
] |
The design load-carying capacities of woden shores depend on factors, such as the wodspecies and properties, and construction methods. This paper focuses on the construction methods,including an upright single shore, group of upright shores, group of inclined shores, butt connections andlap connections. This paper reports experiments to obtain critical loads and then developed an empiricalequation based on Eulers formula for the critical loads and design load-carrying capacities. The testresults show that the critical loads for an upright single wooden shore are greater than the average valuesfor a group of upright shores, and the latter are greater than the average values for a group of inclinedshores. Test results also show that the critical loads become smaller when butt or lap connections areused, butt connections possessing greater critical loads than lap connections. Groups of inclined shores arevery popular at work sites because they have some practical advantages even though they actually possessinferior critical loads. This paper presents an improved setup for constructing groups of inclined shores.With this method, the inclined shores have larger critical loads than upright shores. The design load-carrying capacities were obtained by multiplying the average critical loads by a resistance factor (orstrength reduction factor, f) that were all smaller than 1. This article preliminarily suggests f factorsbased on the test results for the reference of engineers or specification comittees.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000947566
|
oai_dc
|
Experimental investigation on steel-concrete bond in lightweight and normal weight concrete
|
Experimental investigation on steel-concrete bond in lightweight and normal weight concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"How-Ji Chen(Nat. Chung-Hsing University); Chung-Ho Huang(Nat. Chung-Hsing University); Zhang-Yu Kao(Nat. Chung-Hsing University)"
] |
The bonding behaviors of Lightweight Aggregate Concrete (LWAC) and normal weightconcrete were investigated experimentally. Pull-out tests were carried out to measure the bond strengths ofthree groups of specimens with compresive strength levels of 60, 40, and 20 MPa, respectively. Testresults showed that the difference in the bond failure pattern between LWAC and normal weight concretewas significant as the concrete compressive strength became lower than 40 MPa. The corresponding bondstrengths of LWAC were lower than that for normal weight concrete. As the compresive strength ofconcrete became relatively high (> 40 MPa), a bond failure pattern in normal weight concrete occurredthat was similar to that in LWAC. The bond strength of LWAC is higher than that for normal weightconcrete because it possesses higher mortar strength. Stirrup use leads to an increase of approximately20% in nominal bond strength for both types of concrete at any strength level.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001197897
|
oai_dc
|
Orthotropic sandwich plates with interlayer slip and under edgewise loads
|
Orthotropic sandwich plates with interlayer slip and under edgewise loads
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"R. Hussein(Syracuse)"
] |
An elasticity solution for sandwich plates assembled with non-rigid bonding and subjected toedgewise loads is presented. The solution satisfies the equilibrium equations of the face and coreelements, the compatibility equations of stresses and strains at the interfaces, and the boundary conditions.To investigate the effects of bonding stiffnesses on the responses of sandwich plates, numericalevaluations are conducted. The results obtained have shown that the bonding stiffness, up to a certainlevel, has a strong effect on the plate mechanical response. Beyond this level, the usual assumption ofperfect bonding used in classical theories is quite acceptable. An answer to what constitutes perfectbonding is found in terms of the ratio of the core stiffness to the bonding stiffness.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115203
|
oai_dc
|
Deformation-based vulnerability functions for RC bridges
|
Deformation-based vulnerability functions for RC bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. S. Elnashai(Univ. Illinois); B. Borzi(EQE International Ltd.); S. Vlachos(Thomi Engineering)"
] |
There is an ever-increasing demand for assessment of earthquake effects on transportationstructures, emphasised by the crippling consequences of recent earthquakes hitting developed countriesreliant on road transportation. In this work, vulnerability functions for RC bridges are derived analyticallyusing advanced material characterisation, high quality earthquake records and adaptive inelastic dynamicanalysis techniques. Four limit states are employed, all based on deformational quantities, in line withrecent development of deformation-based seismic assessment. The analytically-derived vulnerabilityfunctions are then compared to a data set comprising observational damage data from the Northridge(California 1994) and Hyogo-ken Nanbu (Kobe 1995) earthquakes. The good agreement gives someconfidence in the derived formulation that is recommended for use in seismic risk assessment.Furthermore, by varying the dimensions of the prototype bridge used in the study, and the span lengthssuported by piers, three more bridges are obtained with diferent overstrength ratios (ratio of design-to-available base shear). The process of derivation of vulnerability functions is repeated and the ensuingrelationships compared. The results point towards the feasibility of deriving scaling factors that may beused to obtain the set of vulnerability functions for a bridge with the knowledge of a genericfunctionand the overstrength ratio. It is demonstrated that this simple procedure gives satisfactory results for thecase considered and may be used in the future to facilitate the process of deriving analytical vulnerabilityfunctions for clases of bridges once a generic relationship is established.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115202
|
oai_dc
|
Shaking tables test and numerical analysis of a combined energy dissipation system with metallic yield dampers and oil dampers
|
Shaking tables test and numerical analysis of a combined energy dissipation system with metallic yield dampers and oil dampers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Qiang Zhou(Wuhan Univ. of Tech.); Xilin Lu(Tongji University)"
] |
A shaking table test on a three-story one-bay steel frame model with metallic yield dampers
and their parallel connection with oil dampers is carried out to study the dynamic characteristics and
seismic performance of the energy dissipation system. It is found from the test that the combined energy
dissipation system has favorable reducing vibration effects on structural displacement, and the structural
peak acceleration can not evidently be reduced under small intensity seismic excitations, but in most cases
the vibration reduction effect is very good under large intensity seismic excitations. Test results also show
that stiffness of the energy dissipation devices should match their damping. Dynamic analysis method and
mechanics models of these two dampers are proposed. In the analysis method, the force-displacement
relationship of the metallic yield damper is represented by an elastic perfectly plastic model, and the
behavior of the oil damper is simulated by a velocity and displacement relative model in which the
contributions of the oil damper to the damping force and stiffness of the system are considered. Validity
of the analytical model and the method is verified through comparison between the results of the shaking
table test and numerical analysis.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115204
|
oai_dc
|
Simplified computational methodology for analysis and studies on behaviour of incrementally launched continuous bridges
|
Simplified computational methodology for analysis and studies on behaviour of incrementally launched continuous bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Saptarshi Sasmal(CSIR campus); K. Ramanjaneyulu(CSIR campus); V. Srinivas(CSIR campus); S. Gopalakrishnan(CSIR campus)"
] |
Incremental launching method is one of the highly competitive techniques for construction ofconcrete bridges. It avoids costly and time consuming form work and centralizes all construction activitiesin a small casting yard, thus saving in cost and time against conventional bridge construction. From thequality point of view, it eliminates the uncertainty of monolithic behaviour by allowing high repetitivenessand industrial environment. But, from analysis and design point of view, the most characteristic aspect ofincrementally launched bridges is that, it has to absorb the streses associated with the temporary supportsthat are gradually taken on by the deck during its launch. So, it is necessary to analyse the structure foreach step of launching which is a tedious and time consuming process. Effect of support settlements ortemperature variation makes the problem more complex. By using transfer matrix method, this problemcan be handled efficiently with minimal computational effort. This paper gives insight into method ofanalysis, formulation for optimization of the structural system, effect of support settlement andtemperature gradient, during construction, on the stress state of incrementally launched bridges.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115205
|
oai_dc
|
Probabilistic determination of initial cables forces of cable-stayed bridges under dead loads
|
Probabilistic determination of initial cables forces of cable-stayed bridges under dead loads
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jin Cheng(Tongji University); Ru-Cheng Xiao(Tongji University); Jian-Jing Jiang(Tsinghua University)"
] |
This paper presents an improved Monte Carlo simulation for the probabilistic determinationof initial cable forces of cable-stayed bridges under dead loads using the response surfaces method. Aresponse surface (i.e. a quadratic response surface without cross-terms) is used to approximate structuralresponse. The use of the response surface eliminates the need to perform a deterministic analysis in eachsimulation loop. In addition, use of the response surface requires fewer simulation loops than conventionalMonte Carlo simulation. Thereby, the computation time is saved significantly. The statistics (e.g. meanvalue, standard deviation) of the structural response are calculated through conventional Monte Carlosimulation method. By using Monte Carlo simulation, it is possible to use the existing deterministic finiteelement code without modifying it. Probabilistic analysis of a truss demonstrates the proposed methodsefficiency and accuracy; probabilistic determination of initial cable forces of a cable-stayed bridge underdead loads verifies the methods applicability.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115116
|
oai_dc
|
Harmonic differntial quadrature(HDQ) for axisymmetric bending analysis of thin isotropic circular plates
|
Harmonic differntial quadrature(HDQ) for axisymmetric bending analysis of thin isotropic circular plates
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Omer Civalek(Firat University); Mehmet Ülker(Firat University)"
] |
Numerical solution to linear bending analysis of circular plates is obtained by the method ofharmonic differential quadrature (HDQ). In the method of differential quadrature (DQ), partial spacederivatives of a function appearing in a diferential equation are approximated by means of a polynomialexpressed as the weighted linear sum of the function values at a preselected grid of discrete points. Themethod of HDQ that was used in the paper proposes a very simple algebraic formula to determine theweighting coefficients required by diferential quadrature approximation without restricting the choice ofmesh grids. Applying this concept to the governing diferential equation of circular plate gives a set oflinear simultaneous equations. Bending moments, stresses values in radial and tangential directions andvertical deflections are found for two diferent types of load. In the present study, the axisymmetricbending behavior is considered. Both the clamped and the simply supported edges are considered asboundary conditions. The obtained results are compared with existing solutions available from analyticaland other numerical results such as finite elements and finite differences methods. A comparison betweenthe HDQ results and the finite difference solutions for one example plate problem is also made. Themethod presented gives accurate results and is computationally efficient.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115156
|
oai_dc
|
J-integral and fatigue life computations in the incremental plasticity analysis of large scale yielding by p-version of F.E.M.
|
J-integral and fatigue life computations in the incremental plasticity analysis of large scale yielding by p-version of F.E.M.
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kwang S. Woo(Wuhan Univ. of Tech.); Chong H. Hong(Tamna University); Prodyot K. Basu(Vandervilt University)"
] |
Since the linear elastic fracture analysis has been proved to be insuficient in predicting thefailure of strain hardening materials, a number of fracture concepts have been studied which remainapplicable in the presence of plasticity near a crack tip. This work thereby presents a new finite elementmodel to predict the elastic-plastic crack-tip field and fatigue life of center-cracked panels(CCP) withductile fracture under large-scale yielding conditions. Also, this study has been carried out to investigatethe path-dependence of J-integral within the plastic zone for elastic-perfectly plastic, bilinear elastic-plastic, and nonlinear elastic-plastic materials. Based on the incremental theory of plasticity, the p-versionfinite element is employed to account for the accurate values of J-integral, the most dominant fractureparameter, and the shape of plastic zone near a crack tip by using the J-integral method. To predict thefatigue life, the conventional Paris law has been modified by substituting the range of J-value denoted byDJ for DK. The experimental fatigue test is conducted with five CCP specimens to validate the accuracyof the proposed model. It is noted that the relationship between the crack length a and DK in LEFManalysis shows a strong linearity, on the other hand, the nonlinear relationship between a and DJ isdetected in EPFM analysis. Therefore, this trend will be depended especially in the case of large scaleyielding. The numerical results by the proposed model are compared with the theoretical solutions inliteratures, experimental results, and the numerical solutions by the conventional h-version of the finiteelement method.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115159
|
oai_dc
|
A mixed 8-node hexahedral element based on the Hu-Washizu principle and the field extrapolation technique
|
A mixed 8-node hexahedral element based on the Hu-Washizu principle and the field extrapolation technique
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yung-I Chen(Bureau of High Speed Rail); Guan-Yuan Wu(Ctr. Police University)"
] |
A mixed eight-node hexahedral element formulated via the Hu-Washizu principle as well asthe field extrapolation technique is presented. The mixed element with only three translational degrees offredom at each node can provide extremely accurate and reliable performance for popular benchmarkproblems such as spacial beams, plates, shells as well as general three-dimensional elasticity problems.Numerical calculations also show that when extremely skewed and coarse meshes and nearlyincompressible materials are used, the proposed mixed element can still possess excellent behaviour. Themixed formulation starts with introduction of a parallelepiped domain associated with the given generaleight-node hexahedral element. Then, the assumed strain field at the nodal level is constructed via the Hu-Washizu variational principle for that associated parallelepiped domain. Finally, the assumed strain field atthe nodal level of the given hexahedral element is established by using the field extrapolation technique,and then by using the trilinear shape functions the assumed strain field of the whole element domain isobtained. All matrices involved in establishing the element stiffness matrix can be evaluated analyticallyand expressed explicitly; however, a 24 by 24 matrix has to be inverted to construct the displacementextrapolation matrix. The proposed hexahedral element satisfies the patch test as long as the element witha shape of parallelepiped.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115158
|
oai_dc
|
Seismic performance and damage assessment of reinforced concrete bridge piers with lap-spliced longitudinal steels
|
Seismic performance and damage assessment of reinforced concrete bridge piers with lap-spliced longitudinal steels
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"정영수(중앙대학교); Chang K. Park(Chung-Ang University); Eun H. Lee(Chung-Ang University)"
] |
It is known that lap splices in the longitudinal reinforcement of reinforced concrete (RC)bridge columns are not desirable for seismic performance, but it is sometimes unavoidable. Lap spliceswere practically located in the potential plastic hinge region of most bridge columns that were constructedbefore the 1992 seismic design provisions of the Korea Bridge Design Specification. The objective of thisresearch is to evaluate the seismic performance of reinforced concrete (RC) bridge piers with lap splicingof longitudinal reinforcement in the plastic hinge region, to develop an enhancement scheme for theirseismic capacity by retrofitting with glassfiber sheets, and to asses a damage of bridge columns subjectedto seismic loadings for the development of rational seismic design provisions in low or moderateseismicity region. Nine (9) test specimens with an aspect ratio of 4 were made with three confinementratios and three types of lap splice. Quasi-static tests were conducted in a displacement-controlled wayunder three different axial loads. A significant reduction of displacement ductility was observed for testcolumns with lap splices of longitudinal reinforcements, whose displacement ductility could be greatlyimproved by externally wrapping with glassfiber sheets in the plastic hinge region. A damage of thelimited ductile specimen was assessed to be relatively small.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000947724
|
oai_dc
|
Long-term flexural cracking of reinforced concrete members
|
Long-term flexural cracking of reinforced concrete members
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rajeh Z. Al-Zaid(King Saud Univ.)"
] |
A rational and simple analytical model to predict the time varying cracking moment ofreinforced concrete sections under sustained loading is developed. The modeling procedure is based onequilibrium and compatibility requirements and takes into account the interdependent effects of creep andshrinkage as well as the presence of axial loading. A parametric study is conducted in which particularconsideration is given to the effects of reinforcement ratio, level of loading, and creep and shrinkagecharacteristics of concrete. It is concluded that the reduction in cracking moment is mainly attributed toshrinkage. The effect of shrinkage is more pronounced at low levels of sustained loading and at highreinforcement ratios. This effect is lessened by the compression steel and creep particularly when theapplied moment is near the cracking moment.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000947726
|
oai_dc
|
Incompatible 3-node interpolation for gradient-dependent plasticity
|
Incompatible 3-node interpolation for gradient-dependent plasticity
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Genda Chen(The Univ. of Southern Queensland); G. Baker(The Univ. of Southern Queensland)"
] |
In gradient-dependent plasticity theory, the yield strength depends on the Laplacian of anequivalent plastic strain measure (hardening parameter), and the consistency condition results in adiferential equation with respect to the plastic multiplier. The plastic multiplier is then discretized inaddition to the usual discretization of the displacements, and the consistency condition is solvedsimultaneously with the equilibrium equations. The disadvantage is that the plastic multiplier requires aHermitian interpolation that has four degrees of freedom at each node. Instead of using a Hermitianinterpolation, in this article, a 3-node incompatible (trigonometric) interpolation is proposed for the plasticmultiplier. This incompatible interpolation uses only the function values of each node, but it is continuousacross element boundaries and its second-order derivatives exist within the elements. It greatly reduces thedegrees of freedom for a problem, and is shown through a numerical example on localization to yieldgood results.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001115157
|
oai_dc
|
Behaviour of composite walls under monotonic and cyclic shear loading
|
Behaviour of composite walls under monotonic and cyclic shear loading
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"K. M. Anwar Hossain(Ryerson University); H. D. Wright(Univ. of Strathclyde)"
] |
The novel form of composite walling system consists of two skins of profiled steel sheetingwith an in-fill of concrete. Such walling system can be used as shear elements in steel framed buildingsubjected to lateral load. This paper presents the results of small-scale model tests on composite wall andits components manufactured from very thin sheeting and micro-concrete tested under monotonic andcyclic shear loading conditions. The heavily instrumented small-scale tests provided information on theload-deformation response, strength, stiffnes, strain condition, sheet-concrete interaction and failuremodes. Analytical models for shear strength and stiffness are derived with some modification factor totake into account the effect of quasi-static cycling loading. The performance of design equations isvalidated through experimental results.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART000947725
|
oai_dc
|
Crack growth life model for fatigue susceptible structural components in aging aircraft
|
Crack growth life model for fatigue susceptible structural components in aging aircraft
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Karen C. Chou(Minnesota State Univ.); Glenn C. Cox(Lockwood Greene Engineers); Allison M. Lockwood(Univ. of Tennessee)"
] |
A total life model was developed to assess the service life of aging aircraft. The primaryfocus of this paper is the development of crack growth life projection using the response surface method.Crack growth life projection is a necessary component of the total life model. The study showed that thenumber of load cycles N needed for a crack to propagate to a specified size can be linearly related to thegeometric parameter, material, and stress level of the component considered when all the variables aretransformed to logarithmic values. By the Central Limit theorem, the ln N was approximated by Gaussiandistribution. This Gaussian model compared well with the histograms of the number of load cyclesgenerated from simulated crack growth curves. The outcome of this study will aid engineers in designingtheir crack growth experiments to develop the stochastic crack growth models for service life assesments.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974483
|
oai_dc
|
System identification of an in-service railroad bridge using wireless smart sensors
|
System identification of an in-service railroad bridge using wireless smart sensors
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Robin E. Kim(University of Illinois); Fernando Moreu(University of Illinois); Billie F. Spencer, Jr(University of Illinois)"
] |
Railroad bridges form an integral part of railway infrastructure throughout the world. Toaccommodate increased axel loads, train speeds, and greater volumes of freight traffic, in the presence ofchanging structural conditions, the load carrying capacity and serviceability of existing bridges must beassessed. One way is through system identification of in-service railroad bridges. To dates, numerousresearchers have reported system identification studies with a large portion of their applications beinghighway bridges. Moreover, most of those models are calibrated at global level, while only a few studiesapplications have used globally and locally calibrated model. To reach the global and local calibration, bothambient vibration tests and controlled tests need to be performed. Thus, an approach for systemidentification of a railroad bridge that can be used to assess the bridge in global and local sense is needed.
This study presents system identification of a railroad bridge using free vibration data. Wireless smartsensors are employed and provided a portable way to collect data that is then used to determine bridgefrequencies and mode shapes. Subsequently, a calibrated finite element model of the bridge provides globaland local information of the bridge. The ability of the model to simulate local responses is validated bycomparing predicted and measured strain in one of the diagonal members of the truss. This researchdemonstrates the potential of using measured field data to perform model calibration in a simple andpractical manner that will lead to better understanding the state of railroad bridges.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974479
|
oai_dc
|
Structural identification of Humber Bridge for performance prognosis
|
Structural identification of Humber Bridge for performance prognosis
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"R. Rahbari(University of Sheffield); J. Niu(Southeast University); J.M.W. Brownjohn(University of Exeter); K.Y. Koo(University of Exeter)"
] |
Structural identification or St-Id is ‘the parametric correlation of structural responsecharacteristics predicted by a mathematical model with analogous characteristics derived from experimentalmeasurements’. This paper describes a St-Id exercise on Humber Bridge that adopted a novel two-stageapproach to first calibrate and then validate a mathematical model. This model was then used to predicteffects of wind and temperature loads on global static deformation that would be practically impossible toobserve. The first stage of the process was an ambient vibration survey in 2008 that used operational modalanalysis to estimate a set of modes classified as vertical, torsional or lateral. In the more recent second stagea finite element model (FEM) was developed with an appropriate level of refinement to provide acorresponding set of modal properties. A series of manual adjustments to modal parameters such as cabletension and bearing stiffness resulted in a FEM that produced excellent correspondence for vertical andtorsional modes, along with correspondence for the lower frequency lateral modes. In the third stage traffic,wind and temperature data along with deformation measurements from a sparse structural health monitoringsystem installed in 2011 were compared with equivalent predictions from the partially validated FEM. Thematch of static response between FEM and SHM data proved good enough for the FEM to be used topredict the un-measurable global deformed shape of the bridge due to vehicle and temperature effects but theFEM had limited capability to reproduce static effects of wind. In addition the FEM was used to showinternal forces due to a heavy vehicle to to estimate the worst-case bearing movements under extremecombinations of wind, traffic and temperature loads. The paper shows that in this case, but with limitations,such a two-stage FEM calibration/validation process can be an effective tool for performance prognosis.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974432
|
oai_dc
|
Control system modeling of stock management for civil infrastructure
|
Control system modeling of stock management for civil infrastructure
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Masato Abé(BMC Corporation)"
] |
Management of infrastructure stock is essential in sustainability of society, and its analysis andoptimization are studied in the light of control system modeling in this paper. At the first part of the paper,cost of stock management is analyzed based on macroscopic statistics on infrastructure stock andeconomical growth. Stock management burden relative to economy is observed to become larger at loweconomic growth periods in developed economies. Then, control system modeling of stock management isintroduced and by augmenting maintenance actions as control input, dynamic behavior of stock is simulatedand compared with existing time history statistics. Assuming steady state conditions, applicability of themodel to cross sectional data is also demonstrated. The proposed model is enhanced so that both preventiveand corrective maintenance can be included as system inputs, i.e., feedforward and feedback control inputs.
Optimal management strategy to achieve specified deteriorated stock level with minimal cost, expressed interms of preventive and corrective maintenance actions, is derived based on estimated parameter values forcorrosion of steel bridges. Relative cost effectiveness of preventive maintenance is shown when targetdeteriorated stock level is lower.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974614
|
oai_dc
|
Performance monitoring of timber structures in underground construction using wireless SmartPlank
|
Performance monitoring of timber structures in underground construction using wireless SmartPlank
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xiaomin Xu(University of Cambridge); Kenichi Soga(University of Cambridge); Sarfraz Nawaz(University of Cambridge); Neil Moss(Transport for London); Keith Bowers(Transport for London); Mohammed Gajia(Transport for London)"
] |
Although timber structures have been extensively used in underground temporary supportingsystem, their actual performance is poorly understood, resulting in potentially conservative andover-engineered design. In this paper, a novel wireless sensor technology, SmartPlank, is introduced tomonitor the field performance of timber structures during underground construction. It consists of a woodenbeam equipped with a streamlined wireless sensor node, two thin foil strain gauges and two temperaturesensors, which enables to measure the strain and temperature at two sides of the beam, and to transmit thisinformation in real-time over an IPv6 (6LowPan) multi-hop wireless mesh network and Internet. FourSmartPlanks were deployed at the London Underground’s Tottenham Court Road (TCR) stationredevelopment site during the Stair 14 excavation, together with seven relay nodes and a gateway. Themonitoring started from August 2013, and will last for one and a half years until the Central Line possessionin 2015. This paper reports both the short-term and long-term performances of the monitored timberstructures. The grouting effect on the short-term performance of timber structures is highlighted; the groutinjection process creates a large downward pressure on the top surface of the SmartPlank. The short and longterm earth pressures applied to the monitored structures are estimated from the measured strains, and theestimated values are compared to the design loads.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974430
|
oai_dc
|
Approaching the assessment of ageing bridge infrastructure
|
Approaching the assessment of ageing bridge infrastructure
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Christian Boller(LZfPQ); Peter Starke(LZfPQ); Gerd Dobmann(LZfPQ); Chen-Ming Kuo(LZfPQ); Chung-Hsin Kuo(LZfPQ)"
] |
In many of the industrialized countries an increasing amount of infrastructure is ageing. This hasbecome specifically critical to bridges which are a major asset with respect to keeping an economy alive.
Life of this infrastructure is scattering but often little quantifiable information is known with respect to itsdamage condition. This article describes how a damage tolerance approach used in aviation today may evenbe applied to civil infrastructure in the sense that operational life can be applied in the context of modern lifecycle management. This can be applied for steel structures as a complete process where much of the damageaccumulation behavior is known and may even be adopted to concrete structures in principle, where much ofthe missing knowledge in damage accumulation has to be substituted by enhanced inspection. Thisenhanced and continuous inspection can be achieved through robotic systems in a first approach as well asbuilt in sensors in the sense of structural health monitoring (SHM).
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974640
|
oai_dc
|
Damage identification of belt conveyor support structure using periodic and isolated local vibration modes
|
Damage identification of belt conveyor support structure using periodic and isolated local vibration modes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Amin Hornarbakhsh(Honarbakhsh Construction Office); Tomonori Nagayama(the University of Tokyo); Shohel Rana(the University of Tokyo); Tomonori Tominaga(Nippon Steel and Sumitomo Metal Corporation); Kazumasa Hisazumi(Nippon Steel and Sumitomo Metal Corporation); Ryoichi Kanno(Nippon Steel and Sumitomo Metal Corporation)"
] |
Due to corrosion, a large number of belt conveyors support structure in industrial plants havedeteriorated. Severe corrosion may result in collapse of the structures. Therefore, practical and effectivestructural assessment techniques are needed. In this paper, damage identification methods based on twospecific local vibration modes, named periodic and isolated local vibration modes, are proposed. Theidentification methods utilize the facts that support structures have many identical members repeated alongthe belt conveyor and there exist some local modes within a small frequency range where vibrations of theseidentical members are much larger than those of the other members. When one of these identical members isdamaged, this member no longer vibrates in those modes. Instead, the member vibrates alone in an isolatedmode with a lower frequency. A damage identification method based on frequencies comparison of thesevibration modes and another method based on amplitude comparison of the periodic local vibration modeare explained. These methods do not require the baseline measurement records of undamaged structure. Themethods is capable of detecting multiple damages simultaneously. The applicability of the methods isexperimentally validated with a laboratory model and a real belt-conveyor support structure.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974487
|
oai_dc
|
A statistical framework with stiffness proportional damage sensitive features for structural health monitoring
|
A statistical framework with stiffness proportional damage sensitive features for structural health monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Luciana Balsamo(Columbia University); Suparno Mukhopadhyay(Columbia University); Raimondo Betti(Columbia University)"
] |
A modal parameter based damage sensitive feature (DSF) is defined to mimic the relativechange in any diagonal element of the stiffness matrix of a model of a structure. The damage assessment isperformed in a statistical pattern recognition framework using empirical complementary cumulativedistribution functions (ECCDFs) of the DSFs extracted from measured operational vibration response data.
Methods are discussed to perform probabilistic structural health assessment with respect to the followingquestions: (a) “Is there a change in the current state of the structure compared to the baseline state?”, (b)“Does the change indicate a localized stiffness reduction or increase?”, with the latter representing asituation of retrofitting operations, and (c) “What is the severity of the change in a probabilistic sense?”. Toidentify a range of normal structural variations due to environmental and operational conditions, lower andupper bound ECCDFs are used to define the baseline structural state. Such an approach attempts to decouple“non-damage” related variations from damage induced changes, and account for the unknownenvironmental/operational conditions of the current state. The damage assessment procedure is discussedusing numerical simulations of ambient vibration testing of a bridge deck system, as well as shake tableexperimental data from a 4-story steel frame.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974413
|
oai_dc
|
Joints: the weak link in bridge structures and lifecycles
|
Joints: the weak link in bridge structures and lifecycles
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Bojidar Yanev(Bridge Inspection & Management)"
] |
The condition of the vehicular bridge network in New York City, as represented by ratingsobtained during biennial inspections is reviewed over a period of three decades. Concurrently, the bridgescomprising the network are considered as networks of structural elements whose condition defines theoverall bridge condition according to New York State assumptions. A knowledge-based matrix ofassessments is used in order to determine each element’s vulnerability and impact within the network of anindividual structure and the network of City bridges. In both networks expansion deck joints emerge as theweak link. Typical joint failures are illustrated. Bridge management options for maintenance, preservation,rehabilitation and replacement are examined in the context of joint performance.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974532
|
oai_dc
|
Posterior density estimation for structural parameters using improved differential evolution adaptive Metropolis algorithm
|
Posterior density estimation for structural parameters using improved differential evolution adaptive Metropolis algorithm
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jin Zhou(Keio University); Akira Mita(Keio University); Liu Mei(Keio University)"
] |
The major difficulty of using Bayesian probabilistic inference for system identification is toobtain the posterior probability density of parameters conditioned by the measured response. The posteriordensity of structural parameters indicates how plausible each model is when considering the uncertainty ofprediction errors. The Markov chain Monte Carlo (MCMC) method is a widespread medium for posteriorinference but its convergence is often slow. The differential evolution adaptive Metropolis-Hasting(DREAM) algorithm boasts a population-based mechanism, which runs multiple different Markov chainssimultaneously, and a global optimum exploration ability. This paper proposes an improved differentialevolution adaptive Metropolis-Hasting algorithm (IDREAM) strategy to estimate the posterior density ofstructural parameters. The main benefit of IDREAM is its efficient MCMC simulation through its use of theadaptive Metropolis (AM) method with a mutation strategy for ensuring quick convergence and robustsolutions. Its effectiveness was demonstrated in simulations on identifying the structural parameters withlimited output data and noise polluted measurements.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974427
|
oai_dc
|
Research and practice of health monitoring for long-span bridges in the mainland of China
|
Research and practice of health monitoring for long-span bridges in the mainland of China
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hui Li(Harbin Institute of Technology); Jinping Ou(Harbin Institute of Technology); Xigang Zhang(CCCC Highway Consultants CO., Ltd); Minshan Pei(CCCC Highway Consultants CO., Ltd); Na Li(CCCC Highway Consultants CO., Ltd)"
] |
The large number of long-span bridges constructed in China motivates the applications ofstructural health monitoring (SHM) technology. Many bridges have been equipped with sophisticated SHMsystems in the mainland of China and in Hong Kong of China. Recently, SHM technology has beenextended to field test systems. In this view, SHM can serve as a tool to develop the methods of life-cycleperformance design, evaluation, maintenance and management of bridges; to develop new structuralanalysis methods through validation and feedback from SHM results; and to understand the behavior ofbridges under natural and man-made disasters, rapidly assess the damage and loss of structures over largeregions after disasters, e.g., earthquake, typhoon, flood, etc. It is hoped that combining analytical methods,numerical simulation, small-scale tests and accelerated durability tests with SHM could become the mainengine driving the development of bridge engineering. This paper demonstrates the above viewpoint.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974712
|
oai_dc
|
An innovative hardware emulated simple passive semi-active controller for vibration control of MR dampers
|
An innovative hardware emulated simple passive semi-active controller for vibration control of MR dampers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jianqiu Zhang(HELLA Group); Anil K. Agrawal(The City College of New York)"
] |
Magneto-Rheological (MR) dampers are being used increasingly because of their adaptability tocontrol algorithms and reliability of passive systems. In this paper, an extensive investigation onperformance of MR dampers in semi-active and passive modes has been carried out. It is observed that theoverall energy dissipation by MR dampers in passive-on modes is higher than that in semi-active modes formost of the competitive semi-active controllers. Based on the energy dissipation pattern, a novel semi-activecontroller, termed as “Simple Passive Semi-Active Controller”, has been proposed for MR dampers. Thiscontroller can be emulated by a simple passive hardware proposed in this paper. The proposed concept ofcontroller “hardware emulation” is innovative and can also be implemented for other semi-active devices forcontrol algorithms of certain form. The effectiveness and reliability of the proposed controller has beeninvestigated extensively through numerical simulations. It has been demonstrated that the proposedcontroller is competitive to or more effective than other widely used / investigated semi-active controllers.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974746
|
oai_dc
|
Enabling role of hybrid simulation across NEES in advancing earthquake engineering
|
Enabling role of hybrid simulation across NEES in advancing earthquake engineering
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Daniel Gomez(Purdue University); Shirley J. Dyke(Purdue University); Amin Maghareh(Purdue University)"
] |
Hybrid simulation is increasingly being recognized as a powerful technique for laboratorytesting. It offers the opportunity for global system evaluation of civil infrastructure systems subject toextreme dynamic loading, often with a significant reduction in time and cost. In this approach, a referencestructure/system is partitioned into two or more substructures. The portion of the structural systemdesignated as ‘physical’ or ‘experimental’ is tested in the laboratory, while other portions are replaced with acomputational model. Many researchers have quite effectively used hybrid simulation (HS) and real-timehybrid simulation (RTHS) methods for examination and verification of existing and new design conceptsand proposed structural systems or devices. This paper provides a detailed perspective of the enabling rolethat HS and RTHS methods have played in advancing the practice of earthquake engineering. Herein, ourfocus is on investigations related to earthquake engineering, those with CURATED data available in theirentirety in the NEES Data Repository. Hybrid simulation is increasingly being recognized as a powerful technique for laboratorytesting. It offers the opportunity for global system evaluation of civil infrastructure systems subject toextreme dynamic loading, often with a significant reduction in time and cost. In this approach, a referencestructure/system is partitioned into two or more substructures. The portion of the structural systemdesignated as ‘physical’ or ‘experimental’ is tested in the laboratory, while other portions are replaced with acomputational model. Many researchers have quite effectively used hybrid simulation (HS) and real-timehybrid simulation (RTHS) methods for examination and verification of existing and new design conceptsand proposed structural systems or devices. This paper provides a detailed perspective of the enabling rolethat HS and RTHS methods have played in advancing the practice of earthquake engineering. Herein, ourfocus is on investigations related to earthquake engineering, those with CURATED data available in theirentirety in the NEES Data Repository.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974470
|
oai_dc
|
Displacement estimation of bridge structures using data fusion of acceleration and strain measurement incorporating finite element model
|
Displacement estimation of bridge structures using data fusion of acceleration and strain measurement incorporating finite element model
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"조수진(울산과학기술원); 윤정방(울산과학기술대학교); 심성한(울산과학기술원)"
] |
Recently, an indirect displacement estimation method using data fusion of acceleration andstrain (i.e., acceleration-strain-based method) has been developed. Though the method showed goodperformance on beam-like structures, it has inherent limitation in applying to more general types of bridgesthat may have complex shapes, because it uses assumed analytical (sinusoidal) mode shapes to map themeasured strain into displacement. This paper proposes an improved displacement estimation method thatcan be applied to more general types of bridges by building the mapping using the finite element model ofthe structure rather than using the assumed sinusoidal mode shapes. The performance of the proposedmethod is evaluated by numerical simulations on a deck arch bridge model and a three-span truss bridgemodel whose mode shapes are difficult to express as analytical functions. The displacements are estimatedby acceleration-based method, strain-based method, acceleration-strain-based method, and the improvedmethod. Then the results are compared with the exact displacement. An experimental validation is alsocarried out on a prestressed concrete girder bridge. The proposed method is found to provide the bestestimate for dynamic displacements in the comparison, showing good agreement with the measurements aswell.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974742
|
oai_dc
|
Evolutionary computational approaches for data-driven modeling of multi-dimensional memory-dependent systems
|
Evolutionary computational approaches for data-driven modeling of multi-dimensional memory-dependent systems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ali Bolourchi(University of Southern California); Sami F. Masri(University of Southern California)"
] |
This study presents a novel approach based on advancements in Evolutionary Computation fordata-driven modeling of complex multi-dimensional memory-dependent systems. The investigated exampleis a benchmark coupled three-dimensional system that incorporates 6 Bouc-Wen elements, and is subjectedto external excitations at three points. The proposed technique of this research adapts Genetic Programmingfor discovering the optimum structure of the differential equation of an auxiliary variable associated withevery specific degree-of-freedom of this system that integrates the imposed effect of vibrations at all otherdegrees-of-freedom. After the termination of the first phase of the optimization process, a system ofdifferential equations is formed that represent the multi-dimensional hysteretic system. Then, the parametersof this system of differential equations are optimized in the second phase using Genetic Algorithms to yieldaccurate response estimates globally, because the separately obtained differential equations are coupledessentially, and their true performance can be assessed only when the entire system of coupled differentialequations is solved. The resultant model after the second phase of optimization is a low-orderlow-complexity surrogate computational model that represents the investigated three-dimensionalmemory-dependent system. Hence, this research presents a promising data-driven modeling technique forobtaining optimized representative models for multi-dimensional hysteretic systems that yield reasonablyaccurate results, and can be generalized to many problems, in various fields, ranging from engineering toeconomics as well as biology
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974538
|
oai_dc
|
Probabilistic condition assessment of structures by multiple FE model identification considering measured data uncertainty
|
Probabilistic condition assessment of structures by multiple FE model identification considering measured data uncertainty
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김현중(서울대학교); 고현무(서울대학교)"
] |
A new procedure is proposed for assessing probabilistic condition of structures consideringeffect of measured data uncertainty. In this procedure, multiple Finite Element (FE) models are identified byusing weighting vectors that represent the uncertainty conditions of measured data. The distribution ofstructural parameters is analysed using a Principal Component Analysis (PCA) in relation to uncertaintyconditions, and the identified models are classified into groups according to their similarity by using aK-means method. The condition of a structure is then assessed probabilistically using FE models in theclassified groups, each of which represents specific uncertainty condition of measured data. Yeondae bridge,a steel-box girder expressway bridge in Korea, is used as an illustrative example. Probabilistic condition ofthe bridge is evaluated by the distribution of load rating factors obtained using multiple FE models. Thenumerical example shows that the proposed method can quantify uncertainty of measured data andsubsequently evaluate efficiently the probabilistic condition of bridges.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974717
|
oai_dc
|
Efficient optimal design of passive structural control applied to isolator design
|
Efficient optimal design of passive structural control applied to isolator design
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mahmoud Kamalzare(University of Southern California); Erik A. Johnson(University of Southern California); Steven F. Wojtkiewicz(Clarkson University)"
] |
Typical base isolated buildings are designed so that the superstructure remains elastic in design-levelearthquakes, though the isolation layer is often quite nonlinear using, e.g., hysteretic elements such as lead-rubberbearings and friction pendulum bearings. Similarly, other well-performing structural control systems keep thestructure within the linear range except during the most extreme of excitations. Design optimization of these isolatorsor other structural control systems requires computationally-expensive response simulations of the (mostly or fully)linear structural system with the nonlinear structural control devices. Standard nonlinear structural analysis algorithmsignore the localized nature of these nonlinearities when computing responses. This paper proposes an approach forthe computationally-efficient optimal design of passive isolators by extending a methodology previously developedby the authors for accelerating the response calculation of mostly linear systems with local features (linear ornonlinear, deterministic or random). The methodology is explained and applied to a numerical example of a baseisolated building with a hysteretic isolation layer. The computational efficiency of the proposed approach is shown tobe significant for this simple problem, and is expected to be even more dramatic for more complex systems.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974466
|
oai_dc
|
Cable with discrete negative stiffness device and viscous damper: passive realization and general characteristics
|
Cable with discrete negative stiffness device and viscous damper: passive realization and general characteristics
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lin Chen(Tongji University); Limin Sun(Tongji University); Satish Nagarajaiah(Rice University)"
] |
Negative stiffness, previously emulated by active or semi-active control for cable vibrationmitigation, is realized passively using a self-contained highly compressed spring, the negative stiffnessdevice (NSD).The NSD installed in parallel with a viscous damper (VD) in the vicinity of cable anchorage,enables increment of damper deformation during cable vibrations and hence increases the attainable cabledamping. Considering the small cable displacement at the damper location, even with the weakening device,the force provided by the NSD-VD assembly is approximately linear. Complex frequency analysis has thusbeen conducted to evaluate the damping effect of the assembly on the cable; the displacement-dependentnegative stiffness is further accounted by numerical analysis, validating the accuracy of the linearapproximation for practical ranges of cable and NSD configurations. The NSD is confirmed to be a practicaland cost-effective solution to improve the modal damping of a cable provided by an external damper,especially for super-long cables where the damper location is particularly limited. Moreover, mathematically,a linear negative stiffness and viscous damping assembly has proven capability to represent active orsemi-active control for simplified cable vibration analysis as reported in the literature, while in these studiesonly the assembly located near cable anchorage has been addressed. It is of considerable interest tounderstand the general characteristics of a cable with the assembly relieving the location restriction, since itis quite practical to have an active controller installed at arbitrary location along the cable span such as byhanging an active tuned mass damper. In this paper the cable frequency variations and damping evolutionswith respect to the arbitrary assembly location are then evaluated and compared to those of a taut cable witha viscous damper at arbitrary location, and novel frequency shifts are observed. The characterized complexfrequencies presented in this paper can be used for preliminary damping effect evaluation of an adaptivepassive or semi-active or active device for cable vibration control.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974429
|
oai_dc
|
Can we substitute the intuition of an experienced bridge inspector by monitoring?
|
Can we substitute the intuition of an experienced bridge inspector by monitoring?
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Helmut Wenzel(VCE Vienna Consulting Engineers ZT GmbH); Hiroshi Tanaka(University of Ottawa); Michaela Höllrigl-Binder(VCE Vienna Consulting Engineers ZT GmbH); Helga Allmer(VCE Vienna Consulting Engineers ZT GmbH)"
] |
Damage quantification is a major goal of the SHM community. Methodologies to introduce aquantity for actual condition of a structure into the assessment process are desired. The idea that thecondition of a structure is represented in the character of its dynamic response is fully accepted by the SHMcommunity. The VCLIFE methodology quantifies condition analyzing input from monitoring.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974410
|
oai_dc
|
Effects of local structural damage in a steel truss bridge on internal dynamic coupling and modal damping
|
Effects of local structural damage in a steel truss bridge on internal dynamic coupling and modal damping
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hiroki Yamaguchi(Saitama University); Yasunao Matsumoto(Saitama University); Tsutomu Yoshioka(Nippon Engineering Consultants Co., Ltd)"
] |
Structural health monitoring of steel truss bridge based on changes in modal properties wasinvestigated in this study. Vibration measurements with five sensors were conducted at an existing Warrentruss bridge with partial fractures in diagonal members before and after an emergency repair work. Modalproperties identified by the Eigensystem Realization Algorithm showed evidences of increases in modaldamping due to the damage in diagonal member. In order to understand the dynamic behavior of the bridgeand possible mechanism of those increases in modal damping, theoretical modal analysis was conductedwith three dimensional frame models. It was found that vibrations of the main truss could be coupledinternally with local vibrations of diagonal members and the degree of coupling could change with structuralchanges in diagonal members. Additional vibration measurements with fifteen sensors were then conductedso as to understand the consistency of those theoretical findings with the actual dynamic behavior. Modalproperties experimentally identified showed that the damping change caused by the damage in diagonalmember described above could have occurred in a diagonal-coupled mode. The results in this study implythat damages in diagonal members could be detected from changes in modal damping of diagonal-coupledmodes.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974663
|
oai_dc
|
Integration of health monitoring and vibration control for smart building structures with time-varying structural parameters and unknown excitations
|
Integration of health monitoring and vibration control for smart building structures with time-varying structural parameters and unknown excitations
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y.L. Xu(The Hong Kong Polytechnic University); Q. Huang(The Hong Kong Polytechnic University); Y. Xia(The Hong Kong Polytechnic University); H.J. Liu(The Hong Kong Polytechnic University)"
] |
When a building structure requires both health monitoring system and vibration control system,integrating the two systems together will be cost-effective and beneficial for creating a smart buildingstructure with its own sensors (nervous system), processors (brain system), and actuators (muscular system).
This paper presents a real-time integrated procedure to demonstrate how health monitoring and vibrationcontrol can be integrated in real time to accurately identify time-varying structural parameters and unknownexcitations on one hand, and to optimally mitigate excessive vibration of the building structure on the otherhand. The basic equations for the identification of time-varying structural parameters and unknownexcitations of a semi-active damper-controlled building structure are first presented. The basic equations forsemi-active vibration control of the building structure with time-varying structural parameters and unknownexcitations are then put forward. The numerical algorithm is finally followed to show how the identificationand the control can be performed simultaneously. The results from the numerical investigation of anexample building demonstrate that the proposed method is feasible and accurate.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974724
|
oai_dc
|
Experimental investigation of an active mass damper system with time delay control algorithm
|
Experimental investigation of an active mass damper system with time delay control algorithm
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Dong-Doo Jang(Korea Railroad Research Institute); Jeongsu Park(KAIST); 정형조(한국과학기술원)"
] |
This paper experimentally investigates the effectiveness and applicability of the time delaycontrol (TDC) algorithm, which is simple and robust to unknown system dynamics and disturbance, for anactive mass damper (AMD) system to mitigate the excessive vibration of a building structure. To this end,the theoretical background including the mathematical formulation of the control system is first described;and then, a thorough experimental study using a shaking table system with a small-scale three-story buildingstructural model is conducted. In the experimental tests, the performance of the proposed control system isexamined by comparing its structural responses with those of the uncontrolled system in the free vibrationand forced vibration cases. It is clearly verified from the test results that the TDC algorithm embedded AMDsystem can effectively reduce the structural response of the building structure
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974734
|
oai_dc
|
Drift displacement data based estimation of cumulative plastic deformation ratios for buildings
|
Drift displacement data based estimation of cumulative plastic deformation ratios for buildings
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Akira Nishitani(Waseda Universty); Chisa Matsui(Tokyo Metropolitan Government); Yushiro Hara(Waseda Univ); Ping Xiang(Waseda Univ); Yoshihiro Nitta(Ashikaga Institute of Technology); Tomohiko Hatada(Kajima Technical Research Institute); Ryota Katamura(Kajima Technical Research Institute); Iwao Matsuya(Nagaoka Univ. of Technology); Takashi Tanii(Waseda Univ)"
] |
The authors’ research group has developed a noncontact type of sensors which directly measurethe inter-story drift displacements of a building during a seismic event. Soon after that event, suchseismically-induced drift displacement data would provide structural engineers with useful information tojudge how the stories have been damaged. This paper presents a scheme of estimating the story cumulativeplastic deformation ratios based on such measured drift displacement information toward the building safetymonitoring. The presented scheme requires the data of story drift displacements and the ground motionacceleration. The involved calculations are rather simple without any detailed information on structuralelements required: the story hysteresis loops are first estimated and then the cumulative plastic deformationratio of each story is evaluated from the estimated hysteresis. The effectiveness of the scheme isdemonstrated by utilizing the data of full-scale building model experiment performed at E-defense andconducting numerical simulations.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974498
|
oai_dc
|
Assessment of modal parameters considering measurement and modeling errors
|
Assessment of modal parameters considering measurement and modeling errors
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Qindan Huang(The University of Akron); Paolo Gardoni(University of Illinois at Urbana-Champaign); Stefan Hurlebaus(Texas A&M University)"
] |
Modal parameters of a structure are commonly used quantities for system identification anddamage detection. With a limited number of studies on the statistics assessment of modal parameters, thispaper presents procedures to properly account for the uncertainties present in the process of extracting modalparameters. Particularly, this paper focuses on how to deal with the measurement error in an ambientvibration test and the modeling error resulting from a modal parameter extraction process. A bootstrapapproach is adopted, when an ensemble of a limited number of noised time-history response recordings isavailable. To estimate the modeling error associated with the extraction process, a model predictionexpansion approach is adopted where the modeling error is considered as an “adjustment” to the predictionobtained from the extraction process. The proposed procedures can be further incorporated into theprobabilistic analysis of applications where the modal parameters are used. This study considers the effectsof the measurement and modeling errors and can provide guidance in allocating resources to improve theestimation accuracy of the modal data. As an illustration, the proposed procedures are applied to extract themodal data of a damaged beam, and the extracted modal data are used to detect potential damage locationsusing a damage detection method. It is shown that the variability in the modal parameters can be consideredto be quite low due to the measurement and modeling errors; however, this low variability has a significantimpact on the damage detection results for the studied beam.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001974407
|
oai_dc
|
Mechanisms of thermally induced deflection of a long-span cable-stayed bridge
|
Mechanisms of thermally induced deflection of a long-span cable-stayed bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yi Zhou(Tongji University); Limin Sun(Tongji University); Zhijian Peng(Construction Development Company)"
] |
Variation of temperature is a primary environmental factor that affects the behavior of structures.
Therefore, understanding the mechanisms of normal temperature-induced variations of structural behavior wouldhelp in distinguishing them from anomalies. In this study, we used the structural health monitoring data of theShanghai Yangtze River Bridge, a steel girder cable-stayed bridge, to investigate the mechanisms of thermallyinduced vertical deflection ( DT ) at mid-span of such bridges. The DT results from a multisource combination ofthermal expansion effects of the cable temperature (TCab ), girder temperature (TGir ), girder differential temperature(TDif ), and tower temperature (TTow ). It could be approximated by multiple linear superpositions under operationalconditions. The sensitivities of DT of the Shanghai Yangtze River Bridge to the above temperatures were in thefollowing order: TCab > TGir > TTow > TDif . However, the direction of the effect of TCab was observed to beopposite to that of the other three temperatures, and the magnitudes of the effects of TCab and TGir were found tobe almost one order greater than those of TDif and TTow . The mechanisms of the thermally induced verticaldeflection variation at mid-span of a cable-stayed bridge as well as the analytical methodology adoptedin this study could be applicable for other long-span cable-stayed bridges.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001869961
|
oai_dc
|
Experimental assessment of the piezoelectric transverse d15 shear sensing mechanism
|
Experimental assessment of the piezoelectric transverse d15 shear sensing mechanism
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Pelin Berik(Johannes Kepler University); Ayech Benjeddou(Institut Supérieur de Mécanique de Paris); Michael Krommer(Johannes Kepler University)"
] |
The piezoelectric transverse d15 shear sensing mechanism is firstly assessed experimentally for a cantilever smart sandwich plate made of a piezoceramic axially poled patched core and glass fiber reinforced polymer composite faces. Different electrical connections are tested for the assessment of the sensor performance under a varying amplitude harmonic (at 24 Hz) force. Also, the dynamic response of the smart sandwich composite structure is monitored using different acquisition devices. The obtained experimentally sensed voltages are compared to those resulting from the benchmark three-dimensional piezoelectric coupled finite element simulations using a commercial code where realistic features, like equipotential conditions on the patches\' electrodes and mechanical updating of the clamp, are considered. Numerically, it is found that the stiffness of the clamp, which is much softer than the ideal one, has an enormous influence on the sensed voltage of its adjacent patch; therefore, sensing with the patch on the free side would be more advantageous for a cantilever configuration. Apart from confirming the latter result, the plate benchmark experimental assessment showed that the parallel connection of its two oppositely poled patches has a moderate performance but better than the clamp side patch acting as an individual sensor.
Key
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001870009
|
oai_dc
|
Analysis of system dynamic influences in robotic actuators with variable stiffness
|
Analysis of system dynamic influences in robotic actuators with variable stiffness
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Philipp Beckerle(Technische Universität Darmstadt); Janis Wojtusch(Technische Universität Darmstadt); Stephan Rinderknecht(Technische Universität Darmstadt,); Oskar von Stryk(Technische Universität Darmstadt)"
] |
In this paper the system dynamic influences in actuators with variable stiffness as contemporary used in robotics for safety and efficiency reasons are investigated. Therefore, different configurations of serial and parallel elasticities are modeled by dynamic equations and linearized transfer functions. The latter ones are used to identify the characteristic behavior of the different systems and to study the effect of the different elasticities. As such actuation concepts are often used to reach energy-efficient operation, a power consumption analysis of the configurations is performed. From the comparison of this with the system dynamics, strategies to select and control stiffness are derived. Those are based on matching the natural frequencies or antiresonance modes of the actuation system to the frequency of the trajectory. Results show that exclusive serial and parallel elasticity can minimize power consumption when tuning the system to the natural frequencies. Antiresonance modes are an additional possibility for stiffness control in the series elastic setup. Configurations combining both types of elasticities do not provide further advantages regarding power reduction but an input parallel elasticity might enable for more versatile stiffness selection. Yet, design and control effort increase in such solutions. Topologies incorporating output parallel elasticity showed not to be beneficial in the chosen example but might do so in specific applications.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001869990
|
oai_dc
|
A dynamic analysis of three-dimensional functionally graded beams by hierarchical models
|
A dynamic analysis of three-dimensional functionally graded beams by hierarchical models
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Gaetano Giunta(Centre de Recherche Public Henri Tudor); Yao Koutsawa(Centre de Recherche Public Henri Tudor); Salim Belouettar(Centre de Recherche Public Henri Tudor); Adriano Calvi(ESTEC - European Space Agency)"
] |
This paper presents a dynamic analysis of three-dimensional beams. Structures made of functionally graded materials are considered. Several higher-order as well as classical theories are derived by means of a compact notation for the a-priori expansion order of the displacement field over the beam cross-section. The governing differential equations and boundary conditions are obtained in a condensed nuclear form that does not depend on the kinematic hypotheses. The problem is, then, exactly solved in space by means of a Navier-type solution, whereas time integration is performed by means of Newmark\'s solution scheme. Slender and short simply supported beams are investigated. Results are validated towards three-dimensional FEM results obtained via the commercial software ANSYS. Numerical investigations show that good accuracy can be obtained through the proposed formulation provided that the appropriate expansion order is considered.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001869954
|
oai_dc
|
Point load actuation on plate structures based on triangular piezoelectric patches
|
Point load actuation on plate structures based on triangular piezoelectric patches
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Gilles Tondreau(ULB); Sudharsana Raamanujan Raman(ULB); Arnaud Deraemaeker(ULB)"
] |
This paper investigates the design of a perfect point load actuator based on flat triangular piezoelectric patches. Applying a difference of electric potential between the electrodes of a triangular patch leads to point loads at the tips and distributed moments along the edges of the electrodes. The previously derived analytical expressions of these forces show that they depend on two factors: the width over height (b/l) ratio of the triangle, and the ratio of the in-plane piezoelectric properties (e31/e32) of the active layer of the piezoelectric patch. In this paper, it is shown that by a proper choice of b/l and of the piezoelectric properties, the moments can be cancelled, so that if one side of the triangle is clamped, a perfect point load actuation can be achieved. This requires e31/e32 to be negative, which imposes the use of interdigitated electrodes instead of continuous ones. The design of two transducers with interdigitated electrodes for perfect point load actuation on a clamped plate is verified with finite element calculations. The first design is based on a full piezoelectric ceramic patch and shows superior actuation performance than the second design based on a piezocomposite patch with a volume fraction of fibres of 86%. The results show that both designs lead to perfect point load actuation while the use of an isotropic PZT patch with continuous electrodes gives significantly different results.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001869997
|
oai_dc
|
Nonhomogeneous atherosclerotic plaque analysis via enhanced 1D structural models
|
Nonhomogeneous atherosclerotic plaque analysis via enhanced 1D structural models
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Alberto Varello(Politecnico di Torino); Erasmo Carrera(Politecnico di Torino)"
] |
The static analysis of structures with arbitrary cross-section geometry and material lamination via a refined one-dimensional (1D) approach is presented in this paper. Higher-order 1D models with a variable order of expansion for the displacement field are developed on the basis of Carrera Unified Formulation (CUF). Classical Euler-Bernoulli and Timoshenko beam theories are obtained as particular cases of the first-order model. Numerical results of displacement, strain and stress are provided by using the finite element method (FEM) along the longitudinal direction for different configurations in excellent agreement with three-dimensional (3D) finite element solutions. In particular, a layered thin-walled cylinder is considered as first assessment with a laminated conventional cross-section. An atherosclerotic plaque is introduced as a typical structure with arbitrary cross-section geometry and studied for both the homogeneous and nonhomogeneous material cases through the 1D variable kinematic models. The analyses highlight limitations of classical beam theories and the importance of higher-order terms in accurately detecting in-plane cross-section deformation without introducing additional numerical problems. Comparisons with 3D finite element solutions prove that 1D CUF provides remarkable three-dimensional accuracy in the analysis of even short and nonhomogeneous structures with arbitrary geometry through a significant reduction in computational cost.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001869948
|
oai_dc
|
Variable kinematic beam elements for electro-mechanical analysis
|
Variable kinematic beam elements for electro-mechanical analysis
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"F. Miglioretti(Politecnico di Torino); E. Carrera(Politecnico di Torino); M. Petrolo(Politecnico di Torino)"
] |
This paper proposes a refined electro-mechanical beam formulation. Lagrange-type polynomials areused to interpolate the unknowns over the beam cross section. Three- (L3), four- (L4), and nine-point(L9) polynomials are considered which lead to linear, bi-linear, and quadratic displacement field approximations over the beam cross-section. Finite elements are obtained by employing the principle of virtualdisplacements in conjunction with the Carrera Unified Formulation (CUF). The finite element matricesand vectors are expressed in terms of fundamental nuclei whose forms do not depend on the assumptions made. Additional refined beam models are implemented by introducing further discretizations, overthe beam cross-section. Some assessments from bibliography have been solved in order to validate theelectro-mechanical formulation. The investigations conducted show that the present formulation is ableto detect the electro-mechanical interaction.
Key
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001870004
|
oai_dc
|
Mechanical properties and deformation behavior of carbon nanotubes calculated by a molecular mechanics approach
|
Mechanical properties and deformation behavior of carbon nanotubes calculated by a molecular mechanics approach
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Oliver Eberhardt(Technische Universität Dresden); Thomas Wallmersperger(Technische Universität Dresden)"
] |
Carbon nanotubes are due to their outstanding mechanical properties destined for a wide range of possible applications. Since the knowledge of the material behavior is vital regarding the possible applications, experimental and theoretical studies have been conducted to investigate the properties of this promising material. The aim of the present research is the calculation of mechanical properties and of the mechanical behavior of single wall carbon nanotubes (SWCNTs). The numerical simulation was performed on basis of a molecular mechanics approach. Within this approach two different issues were taken into account: (i) the nanotube geometry and (ii) the modeling of the covalent bond. The nanotube geometry is captured by two different approaches, the roll-up and the exact polyhedral model. The covalent bond is modeled by a structural molecular mechanics approach according to Li and Chou. After a short introduction in the applied modeling techniques, the results for the Young\'s modulus for several SWCNTs are presented and are discussed extensively. The obtained numerical results are compared to results available in literature and show an excellent agreement. Furthermore, deviations in the geometry stemming from the different models are given and the resulting differences in the numerical findings are shown. Within the investigation of the deformation mechanisms occurring in SWCNTs, the basic contributions of each individual covalent bond are considered. The presented results of this decomposition provide a deeper understanding of the governing deformation mechanisms in SWCNTs.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001869974
|
oai_dc
|
Analytical and higher order finite element hybrid approach for an efficient simulation of ultrasonic guided waves I: 2D-analysis
|
Analytical and higher order finite element hybrid approach for an efficient simulation of ultrasonic guided waves I: 2D-analysis
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Juan M. Vivar-Perez(Institute of Composite Structures and Adaptive Systems); Sascha Duczek(Otto-von-Guericke University of Magdeburg); Ulrich Gabbert(Otto-von-Guericke University of Magdeburg)"
] |
In recent years the interest in online monitoring of lightweight structures with ultrasonic guided waves is steadily growing. Especially the aircraft industry is a driving force in the development of structural health monitoring (SHM) systems. In order to optimally design SHM systems powerful and efficient numerical simulation tools to predict the behaviour of ultrasonic elastic waves in thin-walled structures are required. It has been shown that in real industrial applications, such as airplane wings or fuselages, conventional linear and quadratic pure displacement finite elements commonly used to model ultrasonic elastic waves quickly reach their limits. The required mesh density, to obtain good quality solutions, results in enormous computational costs when solving the wave propagation problem in the time domain. To resolve this problem different possibilities are available. Analytical methods and higher order finite element method approaches (HO-FEM), like p-FEM, spectral elements, spectral analysis and isogeometric analysis, are among them. Although analytical approaches offer fast and accurate results, they are limited to rather simple geometries. On the other hand, the application of higher order finite element schemes is a computationally demanding task. The drawbacks of both methods can be circumvented if regions of complex geometry are modelled using a HO-FEM approach while the response of the remaining structure is computed utilizing an analytical approach. The objective of the paper is to present an efficient method to couple different HO-FEM schemes with an analytical description of an undisturbed region. Using this hybrid formulation the numerical effort can be drastically reduced. The functionality of the proposed scheme is demonstrated by studying the propagation of ultrasonic guided waves in plates, excited by a piezoelectric patch actuator. The actuator is modelled utilizing higher order coupled field finite elements, whereas the homogenous, isotropic plate is described analytically. The results of this \"semi-analytical\" approach highlight the opportunities to reduce the numerical effort if closed-form solutions are partially available.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001869984
|
oai_dc
|
Modelling of aluminium foam sandwich panels
|
Modelling of aluminium foam sandwich panels
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Vincenzo D’Alessandro(Università degli Studi di Napoli “Federico II”,); Giuseppe Petrone(Università degli Studi di Napoli “Federico II”,); Sergio De Rosa(Università degli Studi di Napoli “Federico II”); Francesco Franco(Università degli Studi di Napoli “Federico II”)"
] |
applications thanks to the excellent combination of mechanical properties, high strength and stiffness, with functional ones, thermo-acoustic isolation and vibration damping. These properties strongly depend on the density of the foam, the morphology of the pores, the type (open or closed cells) and the size of the gas bubbles enclosed in the solid material. In this paper, the vibrational performances of two classes of sandwich panels with an Alulight R foam core are studied. Experimental tests, in terms of frequency response function and modal analysis, are performed in order to investigate the effect of different percentage of porosity in the foam, as well as the effect of the random distribution of the gas bubbles. Experimental results are used as a reference for developing numerical models using finite element approach. Firstly, a sensitivity analysis is performed in order to obtain a limit-but-bounded dynamic response, modelling the foam core as a homogeneous one. The experimental-numerical correlation is evaluated in terms of natural frequencies and mode shapes. Afterwards, an update of the previous numerical model is presented, in which the core is not longer modelled as homogeneous. Mass and stiffness are randomly distributed in the core volume, exploring the space of the eigenvectors.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001869941
|
oai_dc
|
Effective electromechanical coupling coefficient of adaptive structures with integrated multi-functional piezoelectric structural fiber composites
|
Effective electromechanical coupling coefficient of adaptive structures with integrated multi-functional piezoelectric structural fiber composites
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yao Koutsawa(Centre de Recherche Public Henri Tudor); Sonnou Tiem(Université de Lomé); Gaetano Giunta(Centre de Recherche Public Henri Tudor); Salim Belouettar(Centre de Recherche Public Henri Tudor)"
] |
This paper presents a linear computational homogenization framework to evaluate the effective (or generalized) electromechanical coupling coefficient (EMCC) of adaptive structures with piezoelectric structural fiber (PSF) composite elements. The PSF consists of a silicon carbide (SiC) or carbon core fiber as reinforcement to a fragile piezo-ceramic shell. For the micro-scale analysis, a micromechanics model based on the variational asymptotic method for unit cell homogenization (VAMUCH) is used to evaluate the overall electromechanical properties of the PSF composites. At the macro-scale, a finite element (FE) analysis with the commercial FE code ABAQUS is performed to evaluate the effective EMCC for structures with the PSF composite patches. The EMCC is postprocessed from free-vibrations analysis under short-circuit (SC) and open-circuit (OC) electrodes of the patches. This linear two-scale computational framework may be useful for the optimal design of active structure multi-functional composites which can be used for multi-functional applications such as structural health monitoring, power harvest, vibration sensing and control, damping, and shape control through anisotropic actuation.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001929407
|
oai_dc
|
Period doubling of the nonlinear dynamical system of an electrostatically actuated micro-cantilever
|
Period doubling of the nonlinear dynamical system of an electrostatically actuated micro-cantilever
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y.M. Chen(Sun Yat-sen University); J.K. Liu(Sun Yat-sen University)"
] |
The paper presents an investigation of the nonlinear dynamical system of an electrostatically actuated micro-cantilever by the incremental harmonic balance (IHB) method. An efficient approach is proposed to tackle the difficulty in expanding the nonlinear terms into truncated Fourier series. With the help of this approach, periodic and multi-periodic solutions are obtained by the IHB method. Numerical examples show that the IHB solutions, provided as many as harmonics are taken into account, are in excellent agreement with numerical results. In addition, an iterative algorithm is suggested to accurately determine period doubling bifurcation points. The route to chaos via period doublings starting from the period-1 or period-3 solution are analyzed according to the Floquet and the Feigenbaum theories.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001929424
|
oai_dc
|
Pose-graph optimized displacement estimation for structural displacement monitoring
|
Pose-graph optimized displacement estimation for structural displacement monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"이동화(한국과학기술원); 명현(한국과학기술원); 전해민(한국과학기술원)"
] |
A visually servoed paired structured light system (ViSP) was recently proposed as a novel estimation method of the 6-DOF (Degree-Of-Freedom) relative displacement in civil structures. In order to apply the ViSP to massive structures, multiple ViSP modules should be installed in a cascaded manner. In this configuration, the estimation errors are propagated through the ViSP modules. In order to resolve this problem, a displacement estimation error back-propagation (DEEP) method was proposed. However, the DEEP method has some disadvantages: the displacement range of each ViSP module must be constrained and displacement errors are corrected sequentially, and thus the entire estimation errors are not considered concurrently. To address this problem, a pose-graph optimized displacement estimation (PODE) method is proposed in this paper. The PODE method is based on a graph-based optimization technique that considers entire errors at the same time. Moreover, this method does not require any constraints on the movement of the ViSP modules. Simulations and experiments are conducted to validate the performance of the proposed method. The results show that the PODE method reduces the propagation errors in comparison with a previous work.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001929408
|
oai_dc
|
Performance analyses of antagonistic shape memory alloy actuators based on recovered strain
|
Performance analyses of antagonistic shape memory alloy actuators based on recovered strain
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zhenyun Shi(BeiHang University); Tianmiao Wang(BeiHang University); Liu Da(BeiHang University)"
] |
In comparison with conventional shape memory actuated structures, antagonistic shape memory alloy (SMA) actuators permits a fully reversible two-way response and higher response frequency. However, excessive internal stress could adversely reduce the stroke of the actuators under repeated use. The two-way shape memory effect might further decrease the range of the recovered strain under actuation of an antagonistic SMA actuator unless additional components (e.g., spring and stopper) are added to regain the overall actuation capability. In this paper, the performance of all four possible types of SMA actuation schemes is investigated in detail with emphasis on five key properties: recovered strain, cyclic degradation, response frequency, self-sensing control accuracy, and controllable maximum output. The testing parameters are chosen based on the maximization of recovered strain. Three types of these actuators are antagonistic SMA actuators, which drive with two active SMA wires in two directions. The antagonistic SMA actuator with an additional pair of springs exhibits wider displacement range, more stable performance under reuse, and faster response, although accurate control cannot be maintained under force interference. With two additional stoppers to prevent the over stretch of the spring, the results showed that the proposed structure could achieve significant improvement on all five properties. It can be concluded that, the last type actuator scheme with additional spring and stopper provide much better applicability than the other three in most conditions. The results of the performance analysis of all four SMA actuators could provide a solid basis for the practical design of SMA actuators.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001929413
|
oai_dc
|
Time-varying physical parameter identification of shear type structures based on discrete wavelet transform
|
Time-varying physical parameter identification of shear type structures based on discrete wavelet transform
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chao Wang(Huazhong University of Science & Technology); Wei-Xin Ren(Hefei University of Technology); Zuo-Cai Wang(Huazhong University of Science & Technology); Hong-Ping Zhu(Huazhong University of Science & Technology)"
] |
This paper proposed a discrete wavelet transform based method for time-varying physical parameter identification of shear type structures. The time-varying physical parameters are dispersed and expanded at multi-scale as profile and detail signal using discrete wavelet basis. To reduce the number of unknown quantity, the wavelet coefficients that reflect the detail signal are ignored by setting as zero value. Consequently, the time-varying parameter can be approximately estimated only using the scale coefficients that reflect the profile signal, and the identification task is transformed to an equivalent time-invariant scale coefficient estimation. The time-invariant scale coefficients can be simply estimated using regular least-squares methods, and then the original time-varying physical parameters can be reconstructed by using the identified time-invariant scale coefficients. To reduce the influence of the ill-posed problem of equation resolving caused by noise, the Tikhonov regularization method instead of regular least-squares method is used in the paper to estimate the scale coefficients. A two-story shear type frame structure with time-varying stiffness and damping are simulated to validate the effectiveness and accuracy of the proposed method. It is demonstrated that the identified time-varying stiffness is with a good accuracy, while the identified damping is sensitive to noise.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001929414
|
oai_dc
|
A new methodology of the development of seismic fragility curves
|
A new methodology of the development of seismic fragility curves
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"이영주(울산과학기술원); Do-Soo Moon(University of Illinois at Urbana-Champaign)"
] |
There are continuous efforts to mitigate structural losses from earthquakes and manage risk through seismic risk assessment; seismic fragility curves are widely accepted as an essential tool of such efforts. Seismic fragility curves can be classified into four groups based on how they are derived: empirical, judgmental, analytical, and hybrid. Analytical fragility curves are the most widely used and can be further categorized into two subgroups, depending on whether an analytical function or simulation method is used. Although both methods have shown decent performances for many seismic fragility problems, they often oversimplify the given problems in reliability or structural analyses owing to their built-in assumptions. In this paper, a new method is proposed for the development of seismic fragility curves. Integration with sophisticated software packages for reliability analysis (FERUM) and structural analysis (ZEUS-NL) allows the new method to obtain more accurate seismic fragility curves for less computational cost. Because the proposed method performs reliability analysis using the first-order reliability method, it provides component probabilities as well as useful byproducts and allows further fragility analysis at the system level. The new method was applied to a numerical example of a 2D frame structure, and the results were compared with those by Monte Carlo simulation. The method was found to generate seismic fragility curves more accurately and efficiently. Also, the effect of system reliability analysis on the development of seismic fragility curves was investigated using the given numerical example and its necessity was discussed.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001929418
|
oai_dc
|
Magnetic circuit optimization in designing Magnetorheological damper
|
Magnetic circuit optimization in designing Magnetorheological damper
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Izyan I.M. Yazid(Universiti Teknologi Malaysia); Saiful A. Mazlan(Universiti Teknologi Malaysia); Fitrian Imaduddin(Universiti Teknologi Malaysia); Takehito Kikuchi(Oita University); Hairi Zamzuri(Universiti Teknologi Malaysia)"
] |
This paper presents the materials analysis for combination of working modes of Magnetorheological (MR) damper. The materials were selected based on the optimum magnetic field strength at the effective areas in order to obtain a better design of MR damper. The design of electromagnetic circuit is one of the critical criteria in designing MR dampers besides the working mechanism and the types of MR damper. The increase in the magnetic field strength is an indication of the improvement in the damping performance of the MR damper. Eventually, the experimental test was performed under quasi-static loading to observe the performances of MR damper in shear mode, squeeze mode and mixed mode. The results showed that the increment of forces was obtained with the increased current due to higher magnetic flux density generated by electromagnetic coils. In general, it can be summarized that the combination of modes generates higher forces than single mode for the same experimental parameters throughout the study.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001929421
|
oai_dc
|
Simulation study of magnetorheological testing cell design by incorporating all basic operating modes
|
Simulation study of magnetorheological testing cell design by incorporating all basic operating modes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mohd J. Mughni(Universiti Teknologi Malaysia); Saiful A. Mazlan(Universiti Teknologi Malaysia); Izyan I.M. Yazid(Universiti Teknologi Malaysia); Mohd A.A. Rahman(Universiti Teknologi Malaysia); Hairi Zamzuri(Universiti Teknologi Malaysia)"
] |
Magnetorheological (MR) fluid is one of the field-responsive fluids that is of interest to many researchers due to its high yield stress value, which depends on the magnetic field strength. Similar to electrorheological (ER) fluid, the combination of working modes is one of the techniques to increase the performance of the fluids with limited focus on MR fluids. In this paper, a novel MR testing cell incorporated with valve, shear and squeeze operational modes is designed and constructed in order to investigate the behaviour of MR fluid in combined mode. The magnetic field distribution in the design concept was analyzed using finite element method in order to verify the effective areas of each mode have the acceptable range of flux density. The annular gap of valve and shear were fixed at 1 mm, while the squeeze gap between the parallel circular surfaces was varied up to 20 mm. Three different coil configurations, which were made up from 23 SWG copper wires were set up in the MR cell. The simulation results indicated that the magnetic field distributed in the squeeze gap was the highest among the other gaps with all coils were subjected to a constant applied current of 1 A. Moreover, the magnetic flux densities in all gaps were in a good range of magnitude based on the simulations that validated the proposed design concept. Hence, the 3D model of the MR testing cell was designed using Solidworks for manufacturing processes.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001929420
|
oai_dc
|
Testing and modelling of shape memory alloy plates for energy dissipators
|
Testing and modelling of shape memory alloy plates for energy dissipators
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Pablo Heresi(Universidad de Chile); Ricardo A. Herrera(Universidad de Chile); Maria O. Moroni(Universidad de Chile)"
] |
Shape memory alloys (SMA) can dissipate energy through hysteresis cycles without significant residual deformation. This paper describes the fabrication and testing of copper-based SMA hourglass-shaped plates for use in energy dissipation devices and the development of a numerical model to reproduce the experiments. The plates were tested under cyclic flexural deformations, showing stable hysteresis cycles without strength degradation. A detailed nonlinear numerical model was developed and validated with the experimental data, using as input the constitutive relationship for the material determined from cyclic tests of material coupons under tension loading. The model adequately reproduces the experimental results. The study is focused on the exploitation of SMA in the martensite phase.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001929425
|
oai_dc
|
Theoretical analyses for a 2-2 cement-based piezoelectric curved composite with electrode layers
|
Theoretical analyses for a 2-2 cement-based piezoelectric curved composite with electrode layers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Taotao Zhang(Beihang University)"
] |
Based on the general theory of elasticity, the static behavior of 2-2 cement-based piezoelectric curved composites is investigated. The actuator consists of 2 cement layers and 1 piezoelectric layer. Considering the electrode layer between the cement layer and the piezoelectric layer as the elastic layer, the exact solutions of the mechanical and electrical fields of the curved composites are obtained by utilizing the Airy stress function method. Furthermore, the theoretical results are compared with the FEM results and good agreements (with almost no error) are obtained, thus proving the validity of this study. Furthermore, the influence of certain parameters is discussed, which can help to get the desired displacements and stresses. Finally, it is seen that the analytical model established in this paper works well, which could benefit the design of this kind of cement-based smart devices.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001929428
|
oai_dc
|
Toward a paradigm for civil structural control
|
Toward a paradigm for civil structural control
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S. Casciati(University of Catania at Siracusa); A.G. Chassiakos(California State University); S.F. Masri(University of Southern California)"
] |
Structural control is a very broad field combining the areas of automatic control and structural engineering, with applications ranging from aerospace and mechanical engineering to building and civil infrastructure systems. In this paper, the focus is placed on civil engineering applications only. The goal is to address the issues concurring to form the scientific paradigm. As a resut, possible future directions of research into this field are identified.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001929409
|
oai_dc
|
An evolutionary fuzzy modelling approach and comparison of different methods for shear strength prediction of high-strength concrete beams without stirrups
|
An evolutionary fuzzy modelling approach and comparison of different methods for shear strength prediction of high-strength concrete beams without stirrups
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mohammad Mohammadhassani(University of Malaya); Hossein Nezamabadi-pour(Shahid Bahonar University of Kerman); Meldi Suhatril(University of Malaya); Mahdi shariati(University of Malaya)"
] |
In this paper, an Adaptive nerou-based inference system (ANFIS) is being used for the prediction of shear strength of high strength concrete (HSC) beams without stirrups. The input parameters comprise of tensile reinforcement ratio, concrete compressive strength and shear span to depth ratio. Additionally, 122 experimental datasets were extracted from the literature review on the HSC beams with some comparable cross sectional dimensions and loading conditions. A comparative analysis has been carried out on the predicted shear strength of HSC beams without stirrups via the ANFIS method with those from the CEB-FIP Model Code (1990), AASHTO LRFD 1994 and CSA A23.3 – 94 codes of design. The shear strength prediction with ANFIS is discovered to be superior to CEB-FIP Model Code (1990), AASHTO LRFD 1994 and CSA A23.3 – 94. The predictions obtained from the ANFIS are harmonious with the test results not accounting for the shear span to depth ratio, tensile reinforcement ratio and concrete compressive strength; the data of the average, variance, correlation coefficient and coefficient of variation (CV) of the ratio between the shear strength predicted using the ANFIS method and the real shear strength are 0.995, 0.014, 0.969 and 11.97%, respectively. Taking a look at the CV index, the shear strength prediction shows better in nonlinear iterations such as the ANFIS for shear strength prediction of HSC beams without stirrups.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001929411
|
oai_dc
|
Simulation of PZT monitoring of reinforced concrete beams retrofitted with CFRP
|
Simulation of PZT monitoring of reinforced concrete beams retrofitted with CFRP
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"C.P. Providakis(Technical University of Crete); K. Stefanaki(Technical University of Crete); T.C. Triantafillou(University of Patras); D. Karabalis(University of Patras); A. Papanicolaou(University of Patras); A. Tsantilis(University of Patras); E. Tzoura(University of Patras)"
] |
A numerical study has been carried out to simulate an innovative monitoring procedure to detect and localize damage in reinforced concrete beams retrofitted with carbon fiber reinforced polymer (CFRP) unidirectional laminates. The main novelty of the present simulation is its ability to conduct the electro-mechanical admittance monitoring technique by considerably compressing the amount of data required for damage detection and localization. A FEM simulation of electromechanical admittance-based sensing technique was employed by applying lead zirconate titanate (PZT) transducers to acquire impedance spectrum signatures. Response surface methodology (RSM) is finally adopted as a tool for solving inverse problems to estimate the location and size of damaged areas from the relationship between damage and electro-mechanical admittance changes computed at PZT transducer surfaces. This statistical metamodel technique allows polynomial models to be produced without requiring complicated modeling or numerous data sets after the generation of damage, leading to considerably lower cost of creating diagnostic database. Finally, a numerical example is carried out regarding a steel-reinforced concrete (RC) beam model monotonically loaded up to its failure which is also retrofitted by a CFRP laminate to verify the validity of the present metamodeling monitoring technique. The load-carrying capacity of concrete is predicted in the present paper by utilizing an Ottosen-type failure surface in order to better take into account the passive confinement behavior of retrofitted concrete material under the application of FRP laminate.
|
토목공학
| null |
kci_detailed_000086.xml
|
|||
ART001929423
|
oai_dc
|
An integrated approach for structural health monitoring using an in-house built fiber optic system and non-parametric data analysis
|
An integrated approach for structural health monitoring using an in-house built fiber optic system and non-parametric data analysis
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Masoud Malekzadeh(University of Central Florida); Necati Catbas(University of Central Florida); Mustafa Gul(University of Alberta); 권일범(한국표준과학연구원)"
] |
Multivariate statistics based damage detection algorithms employed in conjunction with novel sensing technologies are attracting more attention for long term Structural Health Monitoring of civil infrastructure. In this study, two practical data driven methods are investigated utilizing strain data captured from a 4-span bridge model by Fiber Bragg Grating (FBG) sensors as part of a bridge health monitoring study. The most common and critical bridge damage scenarios were simulated on the representative bridge model equipped with FBG sensors. A high speed FBG interrogator system is developed by the authors to collect the strain responses under moving vehicle loads using FBG sensors. Two data driven methods, Moving Principal Component Analysis (MPCA) and Moving Cross Correlation Analysis (MCCA), are coded and implemented to handle and process the large amount of data. The efficiency of the SHM system with FBG sensors, MPCA and MCCA methods for detecting and localizing damage is explored with several experiments. Based on the findings presented in this paper, the MPCA and MCCA coupled with FBG sensors can be deemed to deliver promising results to detect both local and global damage implemented on the bridge structure.
|
토목공학
| null |
kci_detailed_000087.xml
|
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