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ART001450060
|
oai_dc
|
Development and deployment of large scale wireless sensor network on a long-span bridge
|
Development and deployment of large scale wireless sensor network on a long-span bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Shamim N. Pakzad(Lehigh University)"
] |
Testing and validation processes are critical tasks in developing a new hardware platform based on a new technology. This paper describes a series of experiments to evaluate the performance of a newly developed MEMS-based wireless sensor node as part of a wireless sensor network (WSN). The sensor node consists of a sensor board with four accelerometers, a thermometer and filtering and digitization units, and a MICAz mote for control, local computation and communication. The experiments include calibration and linearity tests for all sensor channels on the sensor boards, dynamic range tests to evaluate their performance when subjected to varying excitation, noise characteristic tests to quantify the noise floor of the sensor board, and temperature tests to study the behavior of the sensors under changing temperature profiles. The paper also describes a large-scale deployment of the WSN on a long-span suspension bridge, which lasted over three months and continuously collected ambient vibration and temperature data on the bridge. Statistical modal properties of a bridge tower are presented and compared with similar estimates from a previous deployment of sensors on the bridge and finite element models.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450085
|
oai_dc
|
Wireless operational modal analysis of a multi-span prestressed concrete bridge for structural identification
|
Wireless operational modal analysis of a multi-span prestressed concrete bridge for structural identification
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Matthew J. Whelan(Clarkson University); Michael V. Gangone(Clarkson University); Kerop D. Janoyan(Clarkson University); Neil A. Hoult(Queen's University); Campbell R. Middleton(University of Cambridge); Kenichi Soga(University of Cambridge)"
] |
Low-power radio frequency (RF) chip transceiver technology and the associated structural health monitoring platforms have matured recently to enable high-rate, lossless transmission of measurement data across large-scale sensor networks. The intrinsic value of these advanced capabilities is the allowance for high-quality, rapid operational modal analysis of in-service structures using distributed accelerometers to experimentally characterize the dynamic response. From the analysis afforded through these dynamic data sets, structural identification techniques can then be utilized to develop a well calibrated finite element (FE) model of the structure for baseline development, extended analytical structural evaluation, and load response assessment. This paper presents a case study in which operational modal analysis is performed on a three-span prestressed reinforced concrete bridge using a wireless sensor network. The low-power wireless platform deployed supported a high-rate, lossless transmission protocol enabling real-time remote acquisition of the vibration response as recorded by twenty-nine accelerometers at a 256 Sps sampling rate. Several instrumentation layouts were utilized to assess the global multi-span response using a stationary sensor array as well as the spatially refined response of a single span using roving sensors and reference-based techniques. Subsequent structural identification using FE modeling and iterative updating through comparison with the experimental analysis is then documented to demonstrate the inherent value in dynamic response measurement across structural systems using high-rate wireless sensor networks.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450043
|
oai_dc
|
Reliable multi-hop communication for structural health monitoring
|
Reliable multi-hop communication for structural health monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Tomonori Nagayama(University of Tokyo); Parya Moinzadeh(University of Illinois at Urbana-Champaign); Kirill Mechitov(University of Illinois at Urbana-Champaign); Mitsushi Ushita(University of Tokyo); Noritoshi Makihata(JIP Techno Science Corporation); Masataka Ieiri(JIP Techno Science Corporation); Gul Agha(University of Illinois at Urbana-Champaign); Billie F. Spencer, Jr.(University of Illinois at Urbana-Champaign); Yozo Fujino(The University of Tokyo); Ju-Won Seo(Hyundai Instititue of Construction Technology)"
] |
Wireless smart sensor networks (WSSNs) have been proposed by a number of researchers to evaluate the current condition of civil infrastructure, offering improved understanding of dynamic response through dense instrumentation. As focus moves from laboratory testing to full-scale implementation, the need for multi-hop communication to address issues associated with the large size of civil infrastructure and their limited radio power has become apparent. Multi-hop communication protocols allow sensors to cooperate to reliably deliver data between nodes outside of direct communication range. However, application specific requirements, such as high sampling rates, vast amounts of data to be collected, precise internodal synchronization, and reliable communication, are quite challenging to achieve with generic multi-hop communication protocols. This paper proposes two complementary reliable multi-hop communication solutions for monitoring of civil infrastructure. In the first approach, termed herein General Purpose Multi-hop (GPMH), the wide variety of communication patterns involved in structural health monitoring, particularly in decentralized implementations, are acknowledged to develop a flexible and adaptable any-to-any communication protocol. In the second approach, termed herein Single-Sink Multi-hop (SSMH), an efficient many-to-one protocol utilizing all available RF channels is designed to minimize the time required to collect the large amounts of data generated by dense arrays of sensor nodes. Both protocols adopt the Ad-hoc On-demand Distance Vector (AODV) routing protocol, which provides any-to-any routing and multi-cast capability, and supports a broad range of communication patterns. The proposed implementations refine the routing metric by considering the stability of links, exclude functionality unnecessary in mostly-static WSSNs, and integrate a reliable communication layer with the AODV protocol. These customizations have resulted in robust realizations of multi-hop reliable communication that meet the demands of structural health monitoring.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450036
|
oai_dc
|
Structural health monitoring of a cable-stayed bridge using wireless smart sensor technology: data analyses
|
Structural health monitoring of a cable-stayed bridge using wireless smart sensor technology: data analyses
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"조수진(KAIST); Hongki Jo(University of Illinois at Urbana-Champaign); Shinae Jang(University of Illinois at Urbana-Champaign); 박종웅(University of Illinois at Urbana - Champaign); 정형조(한국과학기술원); 윤정방(한국과학기술원); Billie F. Spencer, Jr.(University of Illinois at Urbana-Champaign); Ju-Won Seo(Hyundai Instititue of Construction Technology)"
] |
This paper analyses the data collected from the 2nd Jindo Bridge, a cable-stayed bridge in Korea that is a structural health monitoring (SHM) international test bed for advanced wireless smart sensors network (WSSN) technology. The SHM system consists of a total of 70 wireless smart sensor nodes deployed underneath of the deck, on the pylons, and on the cables to capture the vibration of the bridge excited by traffic and environmental loadings. Analysis of the data is performed in both the time and frequency domains. Modal properties of the bridge are identified using the frequency domain decomposition and the stochastic subspace identification methods based on the output-only measurements, and the results are compared with those obtained from a detailed finite element model. Tension forces for the 10 instrumented stay cables are also estimated from the ambient acceleration data and compared both with those from the initial design and with those obtained during two previous regular inspections. The results of the data analyses demonstrate that the WSSN-based SHM system performs effectively for this cable-stayed bridge, giving direct access to the physical status of the bridge.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450021
|
oai_dc
|
Flexible smart sensor framework for autonomous structural health monitoring
|
Flexible smart sensor framework for autonomous structural health monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jennifer A. Rice(Texas Tech University); Kirill Mechitov(University of Illinois at Urbana-Champaign); 심성한(울산과학기술원); Tomonori Nagayama(University of Tokyo); Shinae Jang(University of Illinois at Urbana-Champaign); Robin Kim(University of Illinois at Urbana-Champaign); Billie F. Spencer, Jr.(University of Illinois at Urbana-Champaign); Gul Agha(University of Illinois at Urbana-Champaign); Yozo Fujino(The University of Tokyo)"
] |
Wireless smart sensors enable new approaches to improve structural health monitoring (SHM) practices through the use of distributed data processing. Such an approach is scalable to the large number of sensor nodes required for high-fidelity modal analysis and damage detection. While much of the technology associated with smart sensors has been available for nearly a decade, there have been limited numbers of full-scale implementations due to the lack of critical hardware and software elements. This research develops a flexible wireless smart sensor framework for full-scale, autonomous SHM that integrates the necessary software and hardware while addressing key implementation requirements. The Imote2 smart sensor platform is employed, providing the computation and communication resources that support demanding sensor network applications such as SHM of civil infrastructure. A multi-metric Imote2 sensor board with onboard signal processing specifically designed for SHM applications has been designed and validated. The framework software is based on a service-oriented architecture that is modular, reusable and extensible, thus allowing engineers to more readily realize the potential of smart sensor technology. Flexible network management software combines a sleep/wake cycle for enhanced power efficiency with threshold detection for triggering network wide operations such as synchronized sensing or decentralized modal analysis. The framework developed in this research has been validated on a full-scale a cable-stayed bridge in South Korea.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450030
|
oai_dc
|
Structural health monitoring of a cable-stayed bridge using smart sensor technology: deployment and evaluation
|
Structural health monitoring of a cable-stayed bridge using smart sensor technology: deployment and evaluation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Shinae Jang(University of Illinois at Urbana-Champaign); Hongki Jo(University of Illinois at Urbana-Champaign); 조수진(KAIST); Kirill Mechitov(University of Illinois at Urbana-Champaign); Jennifer A. Rice(Texas Tech University); 심성한(울산과학기술원); 정형조(한국과학기술원); 윤정방(한국과학기술원); Billie F. Spencer, Jr.(University of Illinois at Urbana-Champaign); Gul Agha(University of Illinois at Urbana-Champaign)"
] |
Structural health monitoring (SHM) of civil infrastructure using wireless smart sensor networks (WSSNs) has received significant public attention in recent years. The benefits of WSSNs are that they are low-cost, easy to install, and provide effective data management via on-board computation. This paper reports on the deployment and evaluation of a state-of-the-art WSSN on the new Jindo Bridge, a cable-stayed bridge in South Korea with a 344-m main span and two 70-m side spans. The central components of the WSSN deployment are the Imote2 smart sensor platforms, a custom-designed multimetric sensor boards, base stations, and software provided by the Illinois Structural Health Monitoring Project (ISHMP) Services Toolsuite. In total, 70 sensor nodes and two base stations have been deployed to monitor the bridge using an autonomous SHM application with excessive wind and vibration triggering the system to initiate monitoring. Additionally, the performance of the system is evaluated in terms of hardware durability, software stability, power consumption and energy harvesting capabilities. The Jindo Bridge SHM system constitutes the largest deployment of wireless smart sensors for civil infrastructure monitoring to date. This deployment demonstrates the strong potential of WSSNs for monitoring of large scale civil infrastructure.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450075
|
oai_dc
|
Non-invasive acceleration-based methodology for damage detection and assessment of water distribution system
|
Non-invasive acceleration-based methodology for damage detection and assessment of water distribution system
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Masanobu Shinozuka(University of California); Pai H. Chou(University of California); 김세환(단국대학교); Hong Rok Kim(Center of Embedded Software Technology); Debasis Karmakar(University of California); Lu Fei(Southeast University)"
] |
This paper presents the results of a pilot study and verification of a concept of a novel methodology for damage detection and assessment of water distribution system. The unique feature of the proposed noninvasive methodology is the use of accelerometers installed on the pipe surface, instead of pressure sensors that are traditionally installed invasively. Experimental observations show that a sharp change in pressure is always accompanied by a sharp change of pipe surface acceleration at the corresponding locations along the pipe length. Therefore, water pressure-monitoring can be transformed into acceleration-monitoring of the pipe surface. The latter is a significantly more economical alternative due to the use of less expensive sensors such as MEMS (Micro-Electro-Mechanical Systems) or other acceleration sensors. In this scenario, monitoring is made for Maximum Pipe Acceleration Gradient (MPAG) rather than Maximum Water Head Gradient (MWHG). This paper presents the results of a small-scale laboratory experiment that serves as the proof of concept of the proposed technology. The ultimate goal of this study is to improve upon the existing SCADA (Supervisory Control And Data Acquisition) by integrating the proposed non-invasive monitoring techniques to ultimately develop the next generation SCADA system for water distribution systems.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450122
|
oai_dc
|
Concrete structural health monitoring using piezoceramic-based wireless sensor networks
|
Concrete structural health monitoring using piezoceramic-based wireless sensor networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Peng Li(University of Houston); Haichang Gu(University of Houston); Gangbing Song(University of Houston); Rong Zheng(University of Houston); YL Mo(University of Houston)"
] |
Impact detection and health monitoring are very important tasks for civil infrastructures, such as bridges. Piezoceramic based transducers are widely researched for these tasks due to the piezoceramic material inherent advantages of dual sensing and actuation ability, which enables the active sensing method for structural health monitoring with a network of piezoceramic transducers. Wireless sensor networks, which are easy for deployment, have great potential in health monitoring systems for large civil infrastructures to identify early-age damages. However, most commercial wireless sensor networks are general purpose and may not be optimized for a network of piezoceramic based transducers. Wireless networks of piezoceramic transducers for active sensing have special requirements, such as relatively high sampling rate (at a few-thousand Hz), incorporation of an amplifier for the piezoceramic element for actuation, and low energy consumption for actuation. In this paper, a wireless network is specially designed for piezoceramic transducers to implement impact detection and active sensing for structural health monitoring. A power efficient embedded system is designed to form the wireless sensor network that is capable of high sampling rate. A 32 bit RISC wireless microcontroller is chosen as the main processor. Detailed design of the hardware system and software system of the wireless sensor network is presented in this paper. To verify the functionality of the wireless sensor network, it is deployed on a two-story concrete frame with embedded piezoceramic transducers, and the active sensing property of piezoceramic material is used to detect the damage in the structure. Experimental results show that the wireless sensor network can effectively implement active sensing and impact detection with high sampling rate while maintaining low power consumption by performing offline data processing and minimizing wireless communication.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450124
|
oai_dc
|
A wireless guided wave excitation technique based on laser and optoelectronics
|
A wireless guided wave excitation technique based on laser and optoelectronics
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hyun-Jun Park(KAIST, Korea); 손훈(KAIST, Korea); 윤정방(한국과학기술원); Joseph Chung(Hoseo University); 권일범(한국표준과학연구원)"
] |
There are on-going efforts to utilize guided waves for structural damage detection. Active sensing devices such as lead zirconate titanate (PZT) have been widely used for guided wave generation and sensing. In addition, there has been increasing interest in adopting wireless sensing to structural health monitoring (SHM) applications. One of major challenges in wireless SHM is to secure power necessary to operate the wireless sensors. However, because active sensing devices demand relatively high electric power compared to conventional passive sensors such as accelerometers and strain gauges, existing battery technologies may not be suitable for long-term operation of the active sensing devices. To tackle this problem, a new wireless power transmission paradigm has been developed in this study. The proposed technique wirelessly transmits power necessary for PZT-based guided wave generation using laser and optoelectronic devices. First, a desired waveform is generated and the intensity of the laser source is modulated accordingly using an electro-optic modulator (EOM). Next, the modulated laser is wirelessly transmitted to a photodiode connected to a PZT. Then, the photodiode converts the transmitted light into an electric signal and excites the PZT to generate guided waves on the structure where the PZT is attached to. Finally, the corresponding response from the sensing PZT is measured. The feasibility of the proposed method for wireless guided wave generation has been experimentally demonstrated.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450109
|
oai_dc
|
Ultra low-power active wireless sensor for structural health monitoring
|
Ultra low-power active wireless sensor for structural health monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Dao Zhou(Virginia Polytechnic Institute and State University); Dong Sam Ha(Virginia Polytechnic Institute and State University); Daniel J. Inman(Virginia Polytechnic Institute and State University)"
] |
Structural Health Monitoring (SHM) is the science and technology of monitoring and assessing the condition of aerospace, civil and mechanical infrastructures using a sensing system integrated into the structure. Impedance-based SHM measures impedance of a structure using a PZT (Lead Zirconate Titanate) patch. This paper presents a low-power wireless autonomous and active SHM node called Autonomous SHM Sensor 2 (ASN-2), which is based on the impedance method. In this study, we incorporated three methods to save power. First, entire data processing is performed on-board, which minimizes radio transmission time. Considering that the radio of a wireless sensor node consumes the highest power among all modules, reduction of the transmission time saves substantial power. Second, a rectangular pulse train is used to excite a PZT patch instead of a sinusoidal wave. This eliminates a digital-to-analog converter and reduces the memory space. Third, ASN-2 senses the phase of the response signal instead of the magnitude. Sensing the phase of the signal eliminates an analog-to-digital converter and Fast Fourier Transform operation, which not only saves power, but also enables us to use a low-end low-power processor. Our SHM sensor node ASN-2 is implemented using a TI MSP430 microcontroller evaluation board. A cluster of ASN-2 nodes forms a wireless network. Each node wakes up at a predetermined interval, such as once in four hours, performs an SHM operation, reports the result to the central node wirelessly, and returns to sleep. The power consumption of our ASN-2 is 0.15 mW during the inactive mode and 18 mW during the active mode. Each SHM operation takes about 13 seconds to consume 236 mJ. When our ASN-2 operates once in every four hours, it is estimated to run for about 2.5 years with two AAA-size batteries ignoring the internal battery leakage.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450106
|
oai_dc
|
Design, calibration and application of wireless sensors for structural global and local monitoring of civil infrastructures
|
Design, calibration and application of wireless sensors for structural global and local monitoring of civil infrastructures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yan Yu(Dalian University of Technology); Jinping Ou(Dalian University of Technology); Hui Li(Harbin Institute of Technology)"
] |
Structural Health Monitoring (SHM) gradually becomes a technique for ensuring the health and safety of civil infrastructures and is also an important approach for the research of the damage accumulation and disaster evolving characteristics of civil infrastructures. It is attracting prodigious research interests and the active development interests of scientists and engineers because a great number of civil infrastructures are planned and built every year in mainland China. In a SHM system the sheer number of accompanying wires, fiber optic cables, and other physical transmission medium is usually prohibitive, particularly for such structures as offshore platforms and long-span structures. Fortunately, with recent advances in technologies in sensing, wireless communication, and micro electro mechanical systems (MEMS), wireless sensor technique has been developing rapidly and is being used gradually in the SHM of civil engineering structures. In this paper, some recent advances in the research, development, and implementation of wireless sensors for the SHM of civil infrastructures in mainland China, especially in Dalian University of Technology (DUT) and Harbin Institute of Technology (HIT), are introduced. Firstly, a kind of wireless digital acceleration sensors for structural global monitoring is designed and validated in an offshore structure model. Secondly, wireless inclination sensor systems based on Frequency-hopping techniques are developed and applied successfully to swing monitoring of large-scale hook structures. Thirdly, wireless acquisition systems integrating with different sensing materials, such as Polyvinylidene Fluoride(PVDF), strain gauge, piezoresistive stress/strain sensors fabricated by using the nickel powder-filled cement-based composite, are proposed for structural local monitoring, and validating the characteristics of the above materials. Finally, solutions to the key problem of finite energy for wireless sensors networks are discussed, with future works also being introduced, for example, the wireless sensor networks powered by corrosion signal for corrosion monitoring and rapid diagnosis for large structures.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450120
|
oai_dc
|
Autonomous smart sensor nodes for global and local damage detection of prestressed concrete bridges based on accelerations and impedance measurements
|
Autonomous smart sensor nodes for global and local damage detection of prestressed concrete bridges based on accelerations and impedance measurements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"박재형(부경대학교); 김정태(부경대학교); 홍동수(부경대학교); David Mascarenas(Los Alamos National Laboratory); Jerome Peter Lynch(University of Michigan)"
] |
This study presents the design of autonomous smart sensor nodes for damage monitoring of tendons and girders in prestressed concrete (PSC) bridges. To achieve the objective, the following approaches are implemented. Firstly, acceleration-based and impedance-based smart sensor nodes are designed for global and local structural health monitoring (SHM). Secondly, global and local SHM methods which are suitable for damage monitoring of tendons and girders in PSC bridges are selected to alarm damage occurrence, to locate damage and to estimate severity of damage. Thirdly, an autonomous SHM scheme is designed for PSC bridges by implementing the selected SHM methods. Operation logics of the SHM methods are programmed based on the concept of the decentralized sensor network. Finally, the performance of the proposed system is experimentally evaluated for a lab-scaled PSC girder model for which a set of damage scenarios are experimentally monitored by the developed smart sensor nodes.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450097
|
oai_dc
|
Wireless sensor networks for permanent health monitoring of historic buildings
|
Wireless sensor networks for permanent health monitoring of historic buildings
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Daniele Zonta(University of Trento); Huayong Wu(University of Trento); Matteo Pozzi(University of Trento); Paolo Zanon(University of Trento); Matteo Ceriotti(Bruno Kessler Foundation); Luca Mottola(Swedish Institute of Computer Science); Gian Pietro Picco(University of Trento); Amy L. Murphy(Bruno Kessler Foundation); Stefan Guna(University of Trento); Michele Corrà(Tretec S.r.l.)"
] |
This paper describes the application of a wireless sensor network to a 31 meter-tall medieval tower located in the city of Trento, Italy. The effort is motivated by preservation of the integrity of a set of frescoes decorating the room on the second floor, representing one of most important International Gothic artworks in Europe. The specific application demanded development of customized hardware and software. The wireless module selected as the core platform allows reliable wireless communication at low cost with a long service life. Sensors include accelerometers, deformation gauges, and thermometers. A multi-hop data collection protocol was applied in the software to improve the system flexibility and scalability. The system has been operating since September 2008, and in recent months the data loss ratio was estimated as less than 0.01%. The data acquired so far are in agreement with the prediction resulting a priori from the 3-dimensional FEM. Based on these data a Bayesian updating procedure is employed to real-time estimate the probability of abnormal condition states. This first period of operation demonstrated the stability and reliability of the system, and its ability to recognize any possible occurrence of abnormal conditions that could jeopardize the integrity of the frescos.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450119
|
oai_dc
|
Development of a low-cost multifunctional wireless impedance sensor node
|
Development of a low-cost multifunctional wireless impedance sensor node
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"민지영(한국과학기술원); Seunghee Park(Sungkyunkwan University); 윤정방(한국과학기술원); Byunghun Song(Korea Electronics Technology Institute)"
] |
In this paper, a low cost, low power but multifunctional wireless sensor node is presented for the impedance-based SHM using piezoelectric sensors. Firstly, a miniaturized impedance measuring chip device is utilized for low cost and low power structural excitation/sensing. Then, structural damage detection/sensor self-diagnosis algorithms are embedded on the on-board microcontroller. This sensor node uses the power harvested from the solar energy to measure and analyze the impedance data. Simultaneously it monitors temperature on the structure near the piezoelectric sensor and battery power consumption. The wireless sensor node is based on the TinyOS platform for operation, and users can take MATLAB interface for the control of the sensor node through serial communication. In order to validate the performance of this multifunctional wireless impedance sensor node, a series of experimental studies have been carried out for detecting loose bolts and crack damages on lab-scale steel structural members as well as on real steel bridge and building structures. It has been found that the proposed sensor nodes can be effectively used for local wireless health monitoring of structural components and for constructing a low-cost and multifunctional SHM system as place and forget wireless sensors.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450108
|
oai_dc
|
Multi-scale wireless sensor node for health monitoring of civil infrastructure and mechanical systems
|
Multi-scale wireless sensor node for health monitoring of civil infrastructure and mechanical systems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Stuart G. Taylor(Los Alamos National Laboratory); Kevin M. Farinholt(Los Alamos National Laboratory); Gyuhae Park(Los Alamos National Laboratory); Michael D. Todd(University of California); Charles R. Farrar(Los Alamos National Laboratory)"
] |
This paper presents recent developments in an extremely compact, wireless impedance sensor node (the WID3, Wireless Impedance Device) for use in high-frequency impedance-based structural health monitoring (SHM), sensor diagnostics and validation, and low-frequency (< ~1 kHz) vibration data acquisition. The WID3 is equipped with an impedance chip that can resolve measurements up to 100 kHz, a frequency range ideal for many SHM applications. An integrated set of multiplexers allows the end user to monitor seven piezoelectric sensors from a single sensor node. The WID3 combines on-board processing using a microcontroller, data storage using flash memory, wireless communications capabilities, and a series of internal and external triggering options into a single package to realize a truly comprehensive, self-contained wireless active-sensor node for SHM applications. Furthermore, we recently extended the capability of this device by implementing low-frequency analog-to-digital and digital-to-analog converters so that the same device can measure structural vibration data. The compact sensor node collects relatively low-frequency acceleration measurements to estimate natural frequencies and operational deflection shapes, as well as relatively high-frequency impedance measurements to detect structural damage. Experimental results with application to SHM, sensor diagnostics and low-frequency vibration data acquisition are presented.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001450104
|
oai_dc
|
Wireless sensor networks for underground railway applications: case studies in Prague and London
|
Wireless sensor networks for underground railway applications: case studies in Prague and London
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Peter J. Bennett(University of Cambridge); Kenichi Soga(University of Cambridge); Ian Wassell(University of Cambridge); Paul Fidler(University of Cambridge); Keita Abe(Japan Railway Technical Research Institute); Yusuke Kobayashi(Japan Railway Technical Research Institute); Martin Vanicek(Czech Technical University in Prague)"
] |
There is increasing interest in using structural monitoring as a cost effective way of managing risks once an area of concern has been identified. However, it is challenging to deploy an effective, reliable, large-scale, long-term and real-time monitoring system in an underground railway environment (subway / metro). The use of wireless sensor technology allows for rapid deployment of a monitoring scheme and thus has significant potential benefits as the time available for access is often severely limited. This paper identifies the critical factors that should be considered in the design of a wireless sensor network, including the availability of electrical power and communications networks. Various issues facing underground deployment of wireless sensor networks will also be discussed, in particular for two field case studies involving networks deployed for structural monitoring in the Prague Metro and the London Underground. The paper describes the network design, the radio propagation, the network topology as well as the practical issues involved in deploying a wireless sensor network in these two tunnels.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001464260
|
oai_dc
|
Autonomous hardware development for impedance-based structural health monitoring
|
Autonomous hardware development for impedance-based structural health monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Benjamin L. Grisso(Virginia Polytechnic Institute and State University); Daniel J. Inman(Virginia Polytechnic Institute and State University)"
] |
The development of a digital signal processor based prototype is described in relation to continuing efforts for realizing a fully self-contained active sensor system utilizing impedance-based structural health monitoring. The impedance method utilizes a piezoelectric material bonded to the structure under observation to act as both an actuator and sensor. By monitoring the electrical impedance of the piezoelectric material, insights into the health of the structured can be inferred. The active sensing system detailed in this paper interrogates a structure utilizing a self-sensing actuator and a low cost impedance method. Here, all the data processing, storage, and analysis is performed at the sensor location. A wireless transmitter is used to communicate the current status of the structure. With this new low cost, field deployable impedance analyzer, reliance on traditional expensive, bulky, and power consuming impedance analyzers is no longer necessary. A complete power analysis of the prototype is performed to determine the validity of power harvesting being utilized for self-containment of the hardware. Experimental validation of the prototype on a representative structure is also performed and compared to traditional methods of damage detection.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001464263
|
oai_dc
|
Using frequency response function and wave propagation for locating damage in plates
|
Using frequency response function and wave propagation for locating damage in plates
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ser-Tong Quek(National University of Singapore); Puat-Siong Tua(National University of Singapore)"
] |
In this study, the frequency domain method which utilizes the evaluation of changes in the structural mode shape is adopted to identify regions which contain localized damages. Frequency response function (FRF) values corresponding to the modal frequency, analogous to the mode shape coefficients, are used since change in natural frequency of the system is usually insignificant for localized damage. This method requires only few sensors to obtain the dynamic response of the structure at specific locations to determine the FRF via fast-Fourier transform (FFT). Numerical examples of an aluminum plate, which includes damages of varying severity, locations and combinations of multiple locations, are presented to demonstrate the feasibility of the method. An experimental verification of the method is also done using an aluminum plate with two different degrees of damage, namely a half-through notch and a through notch. The inconsistency in attaining the FRF values for practical applications due to varying impact load may be overcome via statistical averaging, although large variations in the loading in terms of the contact duration should still be avoided. Nonetheless, this method needs special attention when the damages induce notable changes in the modal frequency, such as when the damages are of high severity or cover more extensive area or near the boundary where the support condition is modified. This is largely due to the significant decrease in the frequency term compared to the increase in the vibration amplitude. For practical reasons such as the use of limited number of sensors and to facilitate automation, extending the resolution of this method of identification may not be efficient. Hence, methods based on wave propagation can be employed as a complement on the isolated region to provide an accurate localization as well as to trace the geometry of the damage.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001464258
|
oai_dc
|
Estimation of viscous and Coulomb damping from free-vibration data by a least-squares curve-fitting analysis
|
Estimation of viscous and Coulomb damping from free-vibration data by a least-squares curve-fitting analysis
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wesley C. H. Slemp(Virginia Polytechnic Institute and State University); William L. Hallauer, Jr.(Virginia Polytechnic Institute and State University); Rakesh K. Kapania(Virginia Polytechnic Institute and State University)"
] |
The modeling and parameter estimation of a damped one-degree-of-freedom mass-spring system is examined. This paper presents a method for estimating the system parameters (damping coefficients and natural frequency) from measured free-vibration motion of a system that is modeled to include both subcritical viscous damping and kinetic Coulomb friction. The method applies a commercially available least-squares curve-fitting software function to fit the known solution of the equations of motion to the measured response. The method was tested through numerical simulation, and it was applied to experimental data collected from a laboratory massspring apparatus. The mass of this apparatus translates on linear bearings, which are the primary source of light inherent damping. Results indicate that the curve-fitting method is effective and accurate for both perfect and noisy measurements from a lightly damped mass-spring system.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001464264
|
oai_dc
|
Shape memory alloy-based smart RC bridges: overview of state-of-the-art
|
Shape memory alloy-based smart RC bridges: overview of state-of-the-art
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. S. Alam(The University of Western Ontario); M. Nehdi(The University of Western Ontario); M. A. Youssef(The University of Western Ontario)"
] |
Shape Memory Alloys (SMAs) are unique materials with a paramount potential for various applications in bridges. The novelty of this material lies in its ability to undergo large deformations and return to its undeformed shape through stress removal (superelasticity) or heating (shape memory effect). In particular, Ni-Ti alloys have distinct thermomechanical properties including superelasticity, shape memory effect, and hysteretic damping. SMA along with sensing devices can be effectively used to construct smart Reinforced Concrete (RC) bridges that can detect and repair damage, and adapt to changes in the loading conditions. SMA can also be used to retrofit existing deficient bridges. This includes the use of external post-tensioning, dampers, isolators and/or restrainers. This paper critically examines the fundamental characteristics of SMA and available sensing devices emphasizing the factors that control their properties. Existing SMA models are discussed and the application of one of the models to analyze a bridge pier is presented. SMA applications in the construction of smart bridge structures are discussed. Future trends and methods to achieve smart bridges are also proposed.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001464259
|
oai_dc
|
PVDF interdigitated transducer for generating and detecting Lamb waves in plates
|
PVDF interdigitated transducer for generating and detecting Lamb waves in plates
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hua Gu(University of Illinois at Chicago); George M. Lloyd(ACTA Ins.); Ming L. Wang(University of Illinois at Chicago)"
] |
Piezoelectric materials have been widely used in ultrasonic nondestructive testing (NDT). PZT ceramics can be used to receive and generate surface acoustic waves. It is a common application to attach PZT transducers to the surface of structures for detecting cracks in nondestructive testing. However, not until recently have piezoelectric polymers attracted more and more attention to be the material for interdigitated (IDT) surface and guided-wave transducers. In this paper, an interdigitated gold-on-polyvinylidene fluoride (PVDF) transducer for actuating and sensing Lamb waves has been introduced. A specific etching technology is employed for making the surface electrodes into a certain finger pattern, the spacings of which yield different single mode responses of Lamb waves. Experiments have been performed on steel and carbon fiber composite plates. Results from PVDF IDT sensors have been compared with those from PZT transducers for verification.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001464262
|
oai_dc
|
Parameter identification for nonlinear behavior of RC bridge piers using sequential modified extended Kalman filter
|
Parameter identification for nonlinear behavior of RC bridge piers using sequential modified extended Kalman filter
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kyoung Jae Lee(Daelim Industrial Co. Ltd.); Chung Bang Yun(Korea Advanced Institute of Science and Technology)"
] |
Identification of the nonlinear hysteretic behavior of a reinforced concrete (RC) bridge pier subjected to earthquake loads is carried out based on acceleration measurements of the earthquake motion and bridge responses. The modified Takeda model is used to describe the hysteretic behavior of the RC pier with a small number of parameters, in which the nonlinear behavior is described in logical forms rather than analytical expressions. Hence, the modified extended Kalman filter is employed to construct the state transition matrix using a finite difference scheme. The sequential modified extended Kalman filter algorithm is proposed to identify the unknown parameters and the state vector separately in two steps, so that the size of the problem for each identification procedure may be reduced and possible numerical problems may be avoided. Mode superposition with a modal sorting technique is also proposed to reduce the size of the identification problem for the nonlinear dynamic system with multi-degrees of freedom. Example analysis is carried out for a continuous bridge with a RC pier subjected to earthquake loads in the longitudinal and transverse directions.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471535
|
oai_dc
|
Applications of piezoelectric sensors in geotechnical engineering
|
Applications of piezoelectric sensors in geotechnical engineering
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xiangwu Zeng(Case Western Reserve University)"
] |
Piezoelectric sensors have many applications in geotechnical engineering, especially in characterizing soils through measurement of wave velocities. Since mechanical properties of a material are closely associated with wave velocities, piezoelectric sensors provide a reliable and non-destructive method for the determination of soil properties. This paper presents results of recent research on measuring stiffness of a wide range of soils such as clay, sand, and gravel, characterizing anisotropic properties of soil induced by external loading, measuring stiffness of base and subgrade materials in the pavement, determining soil properties in a centrifuge model during the flight of a centrifuge, and understanding wave propagation in granular materials under micro-gravity environment using this technique.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471533
|
oai_dc
|
Forisome based biomimetic smart materials
|
Forisome based biomimetic smart materials
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Amy Q. Shen(Washington University); B.D. Hamlington(Washington University); Michael Knoblauch(Fraunhofer Institute for Molecular Biology and Applied Ecology); Winfried S. Peters(Liebig University); William F. Pickard(Washington University)"
] |
With the discovery in plants of the proteinaceous forisome crystalloid (Knoblauch, et al. 2003), a novel, non-living, ATP-independent biological material became available to the designer of smart materials for advanced actuating and sensing. The in vitro studies of Knoblauch, et al. show that forisomes (2-4 micron wide and 10-40 micron long) can be repeatedly stimulated to contract and expand anisotropically by shifting either the ambient pH or the ambient calcium ion concentration. Because of their unique abilities to develop and reverse strains greater than 20% in time periods less than one second, forisomes have the potential to outperform current smart materials as advanced, biomimetic, multi-functional, smart sensors or actuators. Probing forisome material properties is an immediate need to lay the foundation for synthesizing forisome-based smart materials for health monitoring of structural integrity in civil infrastructure and for aerospace hardware. Microfluidics is a growing, vibrant technology with increasingly diverse applications. Here, we use microfluidics to study the surface interaction between forisome and substrate and the conformational dynamics of forisomes within a confined geometry to lay the foundation for forisome-based smart materials synthesis in controlled and repeatable environment.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471548
|
oai_dc
|
The controllable fluid dashpot damper performance
|
The controllable fluid dashpot damper performance
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Bijan Samali(University of Technology); Joko Widjaja(University of Technology); John Reizes(University of Technology)"
] |
The use of smart dampers to optimally control the response of structures is on the increase. To maximize the potential use of such damper systems, their accurate modeling and assessment of their performance is of vital interest. In this study, the performance of a controllable fluid dashpot damper, in terms of damper forces, damper dynamic range and damping force hysteretic loops, respectively, is studied mathematically. The study employs a damper Bingham-Maxwell (BingMax) model whose mathematical formulation is developed using a Fourier series technique. The technique treats this one-dimensional Navier-Stokes momentum equation as a linear superposition of initial-boundary value problems (IBVPs): boundary conditions, viscous term, constant Direct Current (DC) induced fluid plug and fluid inertial term. To hold the formulation applicable, the DC current level to the damper is supplied as discrete constants. The formulation and subsequent simulation are validated with experimental results of a commercially available magneto rheological (MR) dashpot damper (Lord model No RD-1005-3) subjected to a sinusoidal stroke motion using a SCHENK material testing machine in the Materials Laboratory at the University of Technology, Sydney.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471536
|
oai_dc
|
Wavelet-based feature extraction for automatic defect classification in strands by ultrasonic structural monitoring
|
Wavelet-based feature extraction for automatic defect classification in strands by ultrasonic structural monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Piervincenzo Rizzo(University of California); Francesco Lanza di Scalea(University of California)"
] |
The structural monitoring of multi-wire strands is of importance to prestressed concrete structures and cable-stayed or suspension bridges. This paper addresses the monitoring of strands by ultrasonic guided waves with emphasis on the signal processing and automatic defect classification. The detection of notch-like defects in the strands is based on the reflections of guided waves that are excited and detected by magnetostrictive ultrasonic transducers. The Discrete Wavelet Transform was used to extract damage-sensitive features from the detected signals and to construct a multi-dimensional Damage Index vector. The Damage Index vector was then fed to an Artificial Neural Network to provide the automatic classification of (a) the size of the notch and (b) the location of the notch from the receiving sensor. Following an optimization study of the network, it was determined that five damage-sensitive features provided the best defect classification performance with an overall success rate of 90.8%. It was thus demonstrated that the wavelet-based multi-dimensional analysis can provide excellent classification performance for notch-type defects in strands.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471537
|
oai_dc
|
Application of operating vehicle load to structural health monitoring of bridges
|
Application of operating vehicle load to structural health monitoring of bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A.K.M. Rafiquzzaman(Ibaraki University); Koichi Yokoyama(Ibaraki University)"
] |
For health monitoring purpose usually the structure is instrumented with a large scale and multi-channel measurement system. In case of highway bridges, operating vehicle could be utilized to reduce the number of measuring devices. First this paper presents a static damage detection algorithm of using operating vehicle load. The technique has been validated by finite element simulation and simple laboratory test. Next the paper presents an approach of using this technique to field application. Here operating vehicle load data has been used by instrumenting the bridge at single location. This approach gives an upper hand to other sophisticated global damage detection methods since it has the potential of reducing the measuring points and devices. It also avoids the application of artificial loading and interruption of any traffic flow.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001536064
|
oai_dc
|
Smart body armor inspired by flow in bone
|
Smart body armor inspired by flow in bone
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Melissa Louise Knothe Tate(Case Western Reserve University)"
] |
An understanding of biomaterials’ smart properties and how biocomposite materials are manufactured by cells provides not only bio-inspiration for new classes of smart actuators and sensors but also foundational technology for smart materials and their manufacture. In this case study, I examine the unique smart properties of bone, which are evident at multiple length scales and how they provide inspiration for novel classes of mechanoactive materials. I then review potential approaches to engineer and manufacture bioinspired smart materials that can be applied to solve currently intractable problems such as the need for “smart” body armor or decor cum personal safety devices.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001536062
|
oai_dc
|
Design rules for creating sensing and self-actuating microcapsules
|
Design rules for creating sensing and self-actuating microcapsules
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"German V. Kolmakov(University of Pittsburgh); Anna C. Balazs(University of Pittsburgh); Victor V. Yashin(University of Pittsburgh)"
] |
Using computational modeling, we design a pair of biomimetic microcapsules that exploit chemical mechanisms to communicate and alter their local environment. As a result, these synthetic objects can undergo autonomous, directed motion. In the simulations, signaling microcapsules release “agonist” particles, while target microcapsules release “antagonist” particles and the permeabilities of both capsule types depend on the local particle concentration in the surrounding solution. Additionally, the released nanoscopic particles can bind to the underlying substrate and thereby create adhesion gradients that propel the microcapsules to move. Hydrodynamic interactions and the feedback mechanism provided by the dissolved particles are both necessary to achieve the cooperative behavior exhibited by these microcapsules. Our model provides a platform for integrating both the spatial and temporal behavior of assemblies of “artificial cells”,and allows us to design a rich variety of structures capable of exhibiting complex dynamics. Due to the celllike attributes of polymeric microcapsules and polymersomes, material systems are available for realizing our predictions.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001536065
|
oai_dc
|
Bio-inspired neuro-symbolic approach to diagnostics of structures
|
Bio-inspired neuro-symbolic approach to diagnostics of structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rahmat A. Shoureshi(University of Denver); Tracy Schantz(University of Denver); Sun W. Lim(University of Denver)"
] |
Recent developments in Smart Structures with very large scale embedded sensors and actuators have introduced new challenges in terms of data processing and sensor fusion. These smart structures are dynamically classified as a large-scale system with thousands of sensors and actuators that form the musculoskeletal of the structure, analogous to human body. In order to develop structural health monitoring and diagnostics with data provided by thousands of sensors, new sensor informatics has to be developed. The focus of our on-going research is to develop techniques and algorithms that would utilize this musculoskeletal system effectively; thus creating the intelligence for such a large-scale autonomous structure. To achieve this level of intelligence, three major research tasks are being conducted: development of a Bio-Inspired data analysis and information extraction from thousands of sensors; development of an analytical technique for Optimal Sensory System using Structural Observability; and creation of a bio-inspired decision-making and control system. This paper is focused on the results of our effort on the first task, namely development of a Neuro-Morphic Engineering approach, using a neuro-symbolic data manipulation, inspired by the understanding of human information processing architecture, for sensor fusion and structural diagnostics.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001536063
|
oai_dc
|
Biomimetics of the extracellular matrix: an integrated three-dimensional fiber-hydrogel composite for cartilage tissue engineering
|
Biomimetics of the extracellular matrix: an integrated three-dimensional fiber-hydrogel composite for cartilage tissue engineering
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jeannine Coburn(Johns Hopkins University); Jennifer Elisseeff(Johns Hopkins University); Matt Gibson(Johns Hopkins University); Pierre Alain Bandalini(Ecole Polytechnique); Christopher Laird(Johns Hopkins University); Hai-Quan Mao(Johns Hopkins University); Lorenzo Moroni(Johns Hopkins University); Dror Seliktar(Technion - Israel Institute of Technology)"
] |
The native extracellular matrix (ECM) consists of an integrated fibrous protein network and proteoglycan-based ground (hydrogel) substance. We designed a novel electrospinning technique to engineer a three dimensional fiber-hydrogel composite that mimics the native ECM structure, is injectable, and has practical macroscale dimensions for clinically relevant tissue defects. In a model system of articular cartilage tissue engineering, the fiber-hydrogel composites enhanced the biological response of adult stem cells, with dynamic mechanical stimulation resulting in near native levels of extracellular matrix. This technology platform was expanded through structural and biochemical modification of the fibers including hydrophilic fibers containing chondroitin sulfate, a significant component of endogenous tissues, and hydrophobic fibers containing ECM microparticles.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001536061
|
oai_dc
|
Synthetic bio-actuators and their applications in biomedicine
|
Synthetic bio-actuators and their applications in biomedicine
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Veronica J. Neiman(University of California); Shyni Varghese(University of California)"
] |
The promise of biomimetic smart structures that can function as sensors and actuators in biomedicine is enormous. Technological development in the field of stimuli-responsive shape memory polymers have opened up a new avenue of applications for polymer-based synthetic actuators. Such synthetic actuators mimic various attributes of living organisms including responsiveness to stimuli, shape memory, selectivity, motility, and organization. This article briefly reviews various stimuli-responsive shape memory polymers and their application as bioactuators. Although the technological advancements have prototyped the potential applications of these smart materials, their widespread commercialization depends on many factors such as sensitivity, versatility, moldability, robustness, and cost.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001536060
|
oai_dc
|
Biomimetic control for redundant and high degree of freedom limb systems: neurobiological modularity
|
Biomimetic control for redundant and high degree of freedom limb systems: neurobiological modularity
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Simon F. Giszter(Drexel University College of Medicine); Corey B. Hart(Drexel University College of Medicine)"
] |
We review the current understanding of modularity in biological motor control and its forms, and then relate this modularity to proposed modular control structures for biomimetic robots. We note the features that are different between the robotic and the biological ‘designs’ with features which have evolved by natural selection, and note those aspects of biology which may be counter-intuitive or unique to the biological controls as we currently understand them. Biological modularity can be divided into kinematic modularity comprised of strokes and cycles: primitives approximating a range of optimization criteria, and execution modularity comprised of kinetic motor primitives: muscle synergies recruited by premotor drives which are most often pulsatile, and which have the biomechanical effect of instantiating a visco-elastic force-field in the limb. The relations of these identified biological elements to kinematic and force-level motor primitives employed in robot control formulations are discussed.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001526604
|
oai_dc
|
In-construction vibration monitoring of a super-tall structure using a long-range wireless sensing system
|
In-construction vibration monitoring of a super-tall structure using a long-range wireless sensing system
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y.Q. Ni(The Hong Kong Polytechnic University); B. Li(The Hong Kong Polytechnic University); K.H. Lam(The Hong Kong Polytechnic University); D.P. Zhu(School of Civil and Environmental Engineering); Y. Wang(School of Civil and Environmental Engineering); J.P. Lynch(University of Michigan); K.H. Law(Stanford University)"
] |
As a testbed for various structural health monitoring (SHM) technologies, a super-tall structure –the 610 m-tall Guangzhou Television and Sightseeing Tower (GTST) in southern China – is currently under construction. This study aims to explore state-of-the-art wireless sensing technologies for monitoring the ambient vibration of such a super-tall structure during construction. The very nature of wireless sensing frees the system from the need for extensive cabling and renders the system suitable for use on construction sites where conditions continuously change. On the other hand, unique technical hurdles exist when deploying wireless sensors in real-life structural monitoring applications. For example, the low-frequency and lowamplitude ambient vibration of the GTST poses significant challenges to sensor signal conditioning and digitization. Reliable wireless transmission over long distances is another technical challenge when utilized in such a super-tall structure. In this study, wireless sensing measurements are conducted at multiple heights of the GTST tower. Data transmission between a wireless sensing device installed at the upper levels of the tower and a base station located at the ground level (a distance that exceeds 443 m) is implemented. To verify the quality of the wireless measurements, the wireless data is compared with data collected by a conventional cable-based monitoring system. This preliminary study demonstrates that wireless sensing technologies have the capability of monitoring the low-amplitude and low-frequency ambient vibration of a super-tall and slender structure like the GTST.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001526611
|
oai_dc
|
System identification of a super high-rise building via a stochastic subspace approach
|
System identification of a super high-rise building via a stochastic subspace approach
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lucia Faravelli(University of Pavia.); Filippo Ubertini(University of Perugia.); Clemente Fuggini(D’Appolonia S.P.A.)"
] |
System identification is a fundamental step towards the application of structural health monitoring and damage detection techniques. On this respect, the development of evolved identification strategies is a priority for obtaining reliable and repeatable baseline modal parameters of an undamaged structure to be adopted as references for future structural health assessments. The paper presents the identification of the modal parameters of the Guangzhou New Television Tower, China, using a data-driven stochastic subspace identification (SSI-data) approach complemented with an appropriate automatic mode selection strategy which proved to be successful in previous literature studies. This well-known approach is based on a clustering technique which is adopted to discriminate structural modes from spurious noise ones. The method is applied to the acceleration measurements made available within the task I of the ANCRiSST benchmark problem, which cover 24 hours of continuous monitoring of the structural response under ambient excitation. These records are then subdivided into a convenient number of data sets and the variability of modal parameter estimates with ambient temperature and mean wind velocity are pointed out. Both 10 minutes and 1 hour long records are considered for this purpose. A comparison with finite element model predictions is finally carried out, using the structural matrices provided within the benchmark, in order to check that all the structural modes contained in the considered frequency interval are effectively identified via SSI-data.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001526606
|
oai_dc
|
Trajectory tracking and active vibration suppression of a smart Single-Link flexible arm using a composite control design
|
Trajectory tracking and active vibration suppression of a smart Single-Link flexible arm using a composite control design
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"E. Mirzaee(Shiraz University.); M. Eghtesad(Shiraz University.); S.A. Fazelzadeh(Shiraz University.)"
] |
This paper is concerned with the trajectory tracking and vibration suppression of a single-link flexible arm by using piezoelectric materials. The dynamics of a single flexible arm with PZT patches as sensor and actuator is derived using extended Hamilton’s principle. Resulting equations show that the coupled beam dynamics including beam vibration and its rigid in-plane rotation takes place in two different time scales. By using singular perturbation theory, the system dynamics is divided into two subsystems. Then, a composite control scheme is elaborated that makes the orientation of the arm track a desired trajectory while suppressing its vibration. The proposed controller has two parts: one is a tracking controller designed for the slow (rigid) subsystem, and the other one is a stabilizing controller for the fast (flexible) subsystem. The outputs considered for the system are angular position of the hub and voltage of the sensor mounted on the structure. To avoid requiring further measurements of beam vibration and also angular velocity of the hub for the fast and slow control laws, respectively, two sliding mode observers for estimating the unknown states are also designed.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001526612
|
oai_dc
|
A comparative study on the subspace based system identification techniques applied on civil engineering structures
|
A comparative study on the subspace based system identification techniques applied on civil engineering structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Pelin Gundes Bakir(Istanbul Technical University.); Serhat Alkan(Istanbul Technical University.); Ender Mete Eksioglu(Istanbul Technical University.)"
] |
The Subspace based System Identification Techniques (SSIT) have been very popular within the research circles in the last decade due to their proven superiority over the other existing system identification techniques. For operational (output only) modal analysis, the stochastic SSIT and for operational modal analysis in the presence of exogenous inputs, the combined deterministic stochastic SSIT have been used in the literature. This study compares the application of the two alternative techniques on a typical school building in Istanbul using 100 Monte Carlo simulations. The study clearly shows that the combined deterministic stochastic SSIT performs superior to the stochastic SSIT when the techniques are applied on noisy data from low to mid rise stiff structures.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001526608
|
oai_dc
|
Damage detection in plates based on pattern search and Genetic algorithms
|
Damage detection in plates based on pattern search and Genetic algorithms
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"G. Ghodrati Amiri(Iran University of Science & Technology.); S.A. Seyed Razzaghi(Iran University of Science & Technology.); A. Bagheri(Iran University of Science & Technology.)"
] |
This paper is aimed at presenting two methods on the basis of pattern search and genetic algorithms to detect and estimate damage in plates using the modal data of a damaged plate. The proposed methods determine the damages of plate structures using optimization of an objective function by pattern search and genetic algorithms. These methods have been applied to two numerical examples, namely fourfixed supported and cantilever plates with and without noise in the modal data and containing one or several damages. The obtained results clearly reveal that the proposed methods can be viewed as a powerful and reliable method for structural damage detection in plates using the modal data.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471627
|
oai_dc
|
Sensor and actuator design for displacement control of continuous systems
|
Sensor and actuator design for displacement control of continuous systems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Michael Krommer(Johannes Kepler University Linz); Hans Irschik(Johannes Kepler University Linz)"
] |
The present paper is concerned with the design of distributed sensors and actuators. Strain type sensors and actuators are considered with their intensity continuously distributed throughout a continuous structure. The sensors measure a weighted average of the strain tensor. As a starting point for their design we introduce the concept of collocated sensors and actuators as well as the so-called natural output. Then we utilize the principle of virtual work for an auxiliary quasi-static problem to assign a mechanical interpretation to the natural output of the sensors to be designed. Therefore, we take the virtual displacements in the principle of virtual work as that part of the displacement in the original problem, which characterizes the deviation from a desired one. We introduce different kinds of distributed sensors, each of them with a mechanical interpretation other than a weighted average of the strain tensor. Additionally, we assign a mechanical interpretation to the collocated actuators as well; for that purpose we use an extended body force analogy. The sensors and actuators are applied to solve the displacement tracking problem for continuous structures; i.e., the problem of enforcing a desired displacement field. We discuss feed forward and feed back control. In the case of feed back control we show that a PD controller can stabilize the continuous system. Finally, a numerical example is presented. A desired deflection of a clamped-clamped beam is tracked by means of feed forward control, feed back control and a combination of the two.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471628
|
oai_dc
|
Analytical solutions for density functionally gradient magneto-electro-elastic cantilever beams
|
Analytical solutions for density functionally gradient magneto-electro-elastic cantilever beams
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Aimin Jiang(Zhejiang University); Haojiang Ding(Zhejiang University)"
] |
The general solution for two-dimensional magneto-electro-elastic media in terms of four harmonic displacement functions is proposed analytically. The expressions of specific solutions of magneto-electro-elastic plane problems with specific body forces are derived. Finally, based on the general solution in the case of distinct eigenvalues and the specific solution for density functionally gradient media, two kinds of beam problems with body forces depending only on the z or x coordinate are solved by the trial-and-error method.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471626
|
oai_dc
|
Broad and stage-based sensing function of HCFRP sensors
|
Broad and stage-based sensing function of HCFRP sensors
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Z.S. Wu(Ibaraki University); C.Q. Yang(Southeast University)"
] |
This paper addresses a new type of broad and stage-based hybrid carbon fiber reinforced polymer (HCFRP) sensor that is suitable for the sensing of infrastructures. The HCFRP sensors, a type of composite sensor, are fabricated with three types of carbon tows of different strength and moduli. For all of the specimens, the active materials are carbon tows by virtue of their electrical conductivity and piezoresistivity. The measurement principles are based on the micro- and macro-fractures of different types of carbon tows. A series of experiments are carried out to investigate the sensing performances of the HCFRP sensors. The main variables include the stack order and volume fractions of different types of carbon tows. It is shown that the change in electrical resistance is in direct proportion to the strain/load in low strain ranges. However, the fractional change in electrical resistance (DR/R0) is smaller than 2% prior to the macro-fractures of carbon tows. In order to improve the resistance changes, measures are taken that can enhance the values of DR/R0 by more than 2 times during low strain ranges. In high strain ranges, the electrical resistance changes markedly with strain/load in a step-wise manner due to the gradual ruptures of different types of carbon tows at different strain amplitudes. The values of DR/R0 due to the fracture of high modulus carbon tows are larger than 36%. Thus, it is demonstrated that the HCFRP sensors have a broad and stage-based sensing capability.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471633
|
oai_dc
|
Sensor technology innovation for the advancement of structural health monitoring: a strategic program of US-China research for the next decade
|
Sensor technology innovation for the advancement of structural health monitoring: a strategic program of US-China research for the next decade
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Steven D. Glaser(University of California); Hui Li(Harbin University of Technology); Ming L. Wang(University of Illinois at Chicago); Jinping Ou(Dalian University of Technology); Jerome Lynch(University of Michigan)"
] |
토목공학
| null |
kci_detailed_000092.xml
|
||||
ART001471630
|
oai_dc
|
Position estimation and control of SMA actuators based on electrical resistance measurement
|
Position estimation and control of SMA actuators based on electrical resistance measurement
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Gangbing Song(University of Houston); Ning Ma(Cyrus Solutions Corporation); Ho-Jun Lee(NASA Johnson Space Center)"
] |
As a functional material, shape memory alloy (SMA) has attracted much attention and research effort to explore its unique properties and its applications in the past few decades. Some of its properties, in particular the electrical resistance (ER) based self-sensing property of SMA, have not been fully studied. Electrical resistance of an SMA wire varies during its phase transformation. This variation is an inherent property of the SMA wire, although it is highly nonlinear with hysteresis. The relationship between the displacement and the electrical resistance of an SMA wire is deterministic and repeatable to some degree, therefore enabling the self-sensing ability of the SMA. The potential of this self-sensing ability has not received sufficient exploration so far, and even the previous studies in literature lack generality. This paper concerns the utilization of the self-sensing property of a spring-biased Nickel-Titanium (Nitinol) SMA actuator for two applications: ER feedback position control of an SMA actuator without a position sensor, and estimation of the opening of a SMA actuated valve. The use of the self-sensing property eliminates the need for a position sensor, therefore reducing the cost and size of an SMA actuator assembly. Two experimental apparatuses are fabricated to facilitate the two proposed applications, respectively. Based on open-loop testing results, the curve fitting technique is used to represent the nonlinear relationships between the displacement and the electrical resistance of the two SMA wire actuators. Using the mathematical models of the two SMA actuators, respectively, a proportional plus derivative controller is designed for control of the SMA wire actuator using only electrical resistance feedback. Consequently, the opening of the SMA actuated valve can be estimated without using an extra sensor.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471631
|
oai_dc
|
Active damage localization technique based on energy propagation of Lamb waves
|
Active damage localization technique based on energy propagation of Lamb waves
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lei Wang(North Carolina State University); F.G. Yuan(North Carolina State University)"
] |
An active damage detection technique is introduced to locate damage in an isotropic plate using Lamb waves. This technique uses a time-domain energy model of Lamb waves in plates that the wave amplitude inversely decays with the propagation distance along a ray direction. Accordingly the damage localization is formulated as a least-squares problem to minimize an error function between the model and the measured data. An active sensing system with integrated actuators/sensors is controlled to excite/receive A0 mode of Lamb waves in the plate. Scattered wave signals from the damage can be obtained by subtracting the baseline signal of the undamaged plate from the recorded signal of the damaged plate. In the experimental study, after collecting the scattered wave signals, a discrete wavelet transform (DWT) is employed to extract the first scattered wave pack from the damage, then an iterative method is derived to solve the least-squares problem for locating the damage. Since this method does not rely on time-of-flight but wave energy measurement, it is more robust, reliable, and noise-tolerant. Both numerical and experimental examples are performed to verify the efficiency and accuracy of the method, and the results demonstrate that the estimated damage position stably converges to the targeted damage.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471588
|
oai_dc
|
Modeling shear capacity of RC slender beams without stirrups using genetic algorithms
|
Modeling shear capacity of RC slender beams without stirrups using genetic algorithms
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Nehdi(The University of Western Ontario); T. Greenough(The University of Western Ontario)"
] |
High-strength concrete (HSC) is becoming increasingly attractive for various construction projects since it offers a multitude of benefits over normal-strength concrete (NSC). Unfortunately, current design provisions for shear capacity of RC slender beams are generally based on data developed for NSC members having a compressive strength of up to 50 MPa, with limited recommendations on the use of HSC. The failure of HSC beams is noticeably different than that of NSC beams since the transition zone between the cement paste and aggregates is much denser in HSC. Thus, unlike NSC beams in which micro-cracks propagate around aggregates, providing significant aggregate interlock, micro-cracks in HSC are trans-granular, resulting in relatively smoother fracture surfaces, thereby inhibiting aggregate interlock as a shear transfer mechanism and reducing the influence of compressive strength on the ultimate shear strength of HSC beams. In this study, a new approach based on genetic algorithms (GAs) was used to predict the shear capacity of both NSC and HSC slender beams without shear reinforcement. Shear capacity predictions of the GA model were compared to calculations of four other commonly used methods: the ACI method, CSA method, Eurocode-2, and Zsutty equation. A parametric study was conducted to evaluate the ability of the GA model to capture the effect of basic shear design parameters on the behaviour of reinforced concrete (RC) beams under shear loading. The parameters investigated include compressive strength, amount of longitudinal reinforcement, and beam depth. It was found that the GA model provided more accurate evaluation of shear capacity compared to that of the other common methods and better captured the influence of the significant shear design parameters. Therefore, the GA model offers an attractive user-friendly alternative to conventional shear design methods.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471586
|
oai_dc
|
Wavelet analysis and enhanced damage indicators
|
Wavelet analysis and enhanced damage indicators
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"N. Lakshmanan(Structural Engineering Research Centre); B.K. Raghuprasad(Indian Institute of Science); K. Muthumani(Structural Engineering Research Centre); N. Gopalakrishnan(Structural Engineering Research Centre); D. Basu(Structural Engineering Research Centre)"
] |
Wavelet transforms are the emerging signal-processing tools for damage identification and time-frequency localization. A small perturbation in a static or dynamic displacement profile could be captured using multi-resolution technique of wavelet analysis. The paper presents the wavelet analysis of damaged linear structural elements using DB4 or BIOR6.8 family of wavelets. Starting with a localized reduction of EI at the mid-span of a simply supported beam, damage modeling is done for a typical steel and reinforced concrete beam element. Rotation and curvature mode shapes are found to be the improved indicators of damage and when these are coupled with wavelet analysis, a clear picture of damage singularity emerges. In the steel beam, the damage is modeled as a rotational spring and for an RC section, moment curvature relationship is used to compute the effective EI. Wavelet analysis is performed for these damage models for displacement, rotation and curvature mode shapes as well as static deformation profiles. It is shown that all the damage indicators like displacement, slope and curvature are magnified under higher modes. A localization scheme with arbitrary location of curvature nodes within a pseudo span is developed for steady state dynamic loads, such that curvature response and damages are maximized and the scheme is numerically tested and proved.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471597
|
oai_dc
|
Design and demonstrators testing of adaptive airfoils and hingeless wings actuated by shape memory alloy wires
|
Design and demonstrators testing of adaptive airfoils and hingeless wings actuated by shape memory alloy wires
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Giuseppe Mirone(University of Catania)"
] |
Two aspects of the design of a small-scale smart wing are addressed in this work, related to the ability of the wing to modify its cross section assuming the shape of two different airfoils and to the possibility of deflecting the profiles near the trailing edge in order to obtain hingeless control surfaces. The actuation is provided by one-way shape memory alloy wires eventually coupled to springs, Shape Memory Alloys (SMAs) being among the most promising materials for this kind of applications. The points to be actuated along the profiles and the displacements to be imposed are selecetd so that they satisfactorily approximate the change from an airfoil to the other and to result in an adequate deflection of the control surface; the actuators and their performances are designed so that an adequate wing stiffness is guaranteed, in order to prevent excessive deformations and undesired airfoil shape variations due to aerodynamic loads. The effect of the pressure distributions, calculated by way of the XFOIL software, and of the actuators loads, is estimated by FE analyses of the loaded wing. Two prototypes are then realised incorporating the variable airfoil and the hingeless aileron features respectively, and the verification of their shapes in both the actuated and non-actuated states, supported by image analysis techniques, confirms that interesting results are achievable with the proposed lay out and design considerations.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471591
|
oai_dc
|
Development of a smart wireless sensing unit using off-the-shelf FPGA hardware and programming products
|
Development of a smart wireless sensing unit using off-the-shelf FPGA hardware and programming products
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chetan Kapoor(University of Oklahoma Norman); Troy L. Graves-Abe(Princeton University Princeton); Jin-Song Pei(University of Oklahoma Norman)"
] |
In this study, Field-Programmable Gate Arrays (FPGAs) are investigated as a practical solution to the challenge of designing an optimal platform for implementing algorithms in a wireless sensing unit for structural health monitoring. Inherent advantages, such as tremendous processing power, coupled with reconfigurable and flexible architecture render FPGAs a prime candidate for the processing core in an optimal wireless sensor unit, especially when handling Digital Signal Processing (DSP) and system identification algorithms. This paper presents an effort to create a proof-of-concept unit, wherein an off-the-shelf FPGA development board, available at a price comparable to a microprocessor development board, was adopted. Data processing functions, including windowing, Fast Fourier Transform (FFT), and peak detection, were implemented in the FPGA using a Matlab Simulink-based high-level abstraction tool rather than hardware descriptive language. Simulations and laboratory tests were carried out to validate the design.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471583
|
oai_dc
|
A bond graph approach to energy efficiency analysis of a self-powered wireless pressure sensor
|
A bond graph approach to energy efficiency analysis of a self-powered wireless pressure sensor
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yong Cui(University of Massachusetts); Robert X. Gao(University of Massachusetts); Dengfeng Yang(University of Massachusetts); David O. Kazmer(University of Massachusetts)"
] |
The energy efficiency of a self-powered wireless sensing system for pressure monitoring in injection molding is analyzed using Bond graph models. The sensing system, located within the mold cavity, consists of an energy converter, an energy modulator, and a ultrasonic signal transmitter. Pressure variation in the mold cavity is extracted by the energy converter and transmitted through the mold steel to a signal receiver located outside of the mold, in the form of ultrasound pulse trains. Through Bond graph models, the energy efficiency of the sensing system is characterized as a function of the configuration of a piezoceramic stack within the energy converter, the pulsing cycle of the energy modulator, and the thicknesses of the various layers that make up the ultrasonic signal transmitter. The obtained energy models are subsequently utilized to identify the minimum level of signal intensity required to ensure successful detection of the ultrasound pulse trains by the signal receiver. The Bond graph models established have shown to be useful in optimizing the design of the various constituent components within the sensing system to achieve high energy conversion efficiency under a compact size, which are critical to successful embedment within the mold structure.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471600
|
oai_dc
|
Double DOF control of an electromechanical integrated toroidal drive
|
Double DOF control of an electromechanical integrated toroidal drive
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lizhong Xu(Yanshan University); Xin Liu(Yanshan University)"
] |
The electromechanical integrated toroidal drive is a new drive system. For the control of the drive, the torque fluctuation and the steady-state errors should be removed and the fast response to the input change should be achieved. In this paper, the torque fluctuation of the drive system is analyzed and expressed as Fourier series forms. The transfer function of the torque control for the drive system is derived from its electromechanical coupled dynamic equations. A 2-DOF control method is used to control the drive system. Using definite parameter relationship of the 2-DOF control system, the steady errors of the torque control for the drive system is removed. Influences of the drive parameters on the control system are investigated. Using proper drive parameters, the response time of the control system is reduced and the quick torque response of the drive system is realized. Using a compensated input voltage, the torque fluctuation of the drive system is removed as well. The compensated input voltage can be obtained from the torque fluctuation equation and the transfer function. These research results are useful for designing control system of the new drive.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471690
|
oai_dc
|
Seismic protection of base isolated structures using smart passive control system
|
Seismic protection of base isolated structures using smart passive control system
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"정형조(한국과학기술원); Kang-Min Choi(KAIST); Kyu-Sik Park(University of Illinois at Urbana Champaign); Sang-Won Cho(The University of Western Ontario)"
] |
The effectiveness of the newly developed smart passive control system employing a magnetorheological (MR) damper and an electromagnetic induction (EMI) part for seismic protection of base isolated structures is numerically investigated. An EMI part in the system consists of a permanent magnet and a coil, which changes the kinetic energy of the deformation of an MR damper into the electric energy (i.e. the induced current) according to the Faraday law of electromagnetic induction. In the smart passive control system, the damping characteristics of an MR damper are varied with the current input generated from an EMI part. Hence, it does not need any control system consisting of sensors, a controller and an external power source. This makes the system much simpler as well as more economic. To verify the efficacy of the smart passive control system, a series of numerical simulations are carried out by considering the benchmark base isolated structure control problems. The numerical simulation results show that the smart passive control system has the comparable control performance to the conventional MR damper-based semiactive control system. Therefore, the smart passive control system could be considered as one of the promising control devices for seismic protection of seismically excited base isolated structures.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471666
|
oai_dc
|
Issues in structural health monitoring employing smart sensors
|
Issues in structural health monitoring employing smart sensors
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"T. Nagayama(University of Tokyo); 심성한(울산과학기술원); Y. Miyamori(Kitami Institute of Technology); B.F. Spencer, Jr.(University of Illinois at Urbana-Champaign)"
] |
Smart sensors densely distributed over structures can provide rich information for structural monitoring using their onboard wireless communication and computational capabilities. However, issues such as time synchronization error, data loss, and dealing with large amounts of harvested data have limited the implementation of full-fledged systems. Limited network resources (e.g. battery power, storage space, bandwidth, etc.) make these issues quite challenging. This paper first investigates the effects of time synchronization error and data loss, aiming to clarify requirements on synchronization accuracy and communication reliability in SHM applications. Coordinated computing is then examined as a way to manage large amounts of data.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471651
|
oai_dc
|
Vibration-based damage detection in beams using genetic algorithm
|
Vibration-based damage detection in beams using genetic algorithm
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김정태(부경대학교); 박재형(부경대학교); Han-Sam Yoon(Pukyong National University); Jin-Hak Yi(Korea Ocean Research and Development Institute)"
] |
In this paper, an improved GA-based damage detection algorithm using a set of combined modal features is proposed. Firstly, a new GA-based damage detection algorithm is formulated for beam-type structures. A schematic of the GA-based damage detection algorithm is designed and objective functions using several modal features are selected for the algorithm. Secondly, experimental modal tests are performed on free-free beams. Modal features such as natural frequency, mode shape, and modal strain energy are experimentally measured before and after damage in the test beams. Finally, damage detection exercises are performed on the test beam to evaluate the feasibility of the proposed method. Experimental results show that the damage detection is the most accurate when frequency changes combined with modal strain-energy changes are used as the modal features for the proposed method.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471679
|
oai_dc
|
Variability of measured modal frequencies of a cable-stayed bridge under different wind conditions
|
Variability of measured modal frequencies of a cable-stayed bridge under different wind conditions
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y.Q. Ni(The Hong Kong Polytechnic University); J.M. Ko(The Hong Kong Polytechnic University); X.G. Hua(The Hong Kong Polytechnic University); H.F. Zhou(The Hong Kong Polytechnic University)"
] |
A good understanding of normal modal variability of civil structures due to varying environmental conditions such as temperature and wind is important for reliable performance of vibration-based damage detection methods. This paper addresses the quantification of wind-induced modal variability of a cable-stayed bridge making use of one-year monitoring data. In order to discriminate the wind-induced modal variability from the temperature-induced modal variability, the one-year monitoring data are divided into two sets: the first set includes the data obtained under weak wind conditions (hourly-average wind speed less than 2 m/s) during all four seasons, and the second set includes the data obtained under both weak and strong (typhoon) wind conditions during the summer only. The measured modal frequencies and temperatures of the bridge obtained from the first set of data are used to formulate temperature-frequency correlation models by means of artificial neural network technique. Before the second set of data is utilized to quantify the wind-induced modal variability, the effect of temperature on the measured modal frequencies is first eliminated by normalizing these modal frequencies to a reference temperature with the use of the temperature-frequency correlation models. Then the wind-induced modal variability is quantitatively evaluated by correlating the normalized modal frequencies for each mode with the wind speed measurement data. It is revealed that in contrast to the dependence of modal frequencies on temperature, there is no explicit correlation between the modal frequencies and wind intensity. For most of the measured modes, the modal frequencies exhibit a slightly increasing trend with the increase of wind speed in statistical sense. The relative variation of the modal frequencies arising from wind effect (with the maximum hourly-average wind speed up to 17.6 m/s) is estimated to range from 1.61% to 7.87% for the measured 8 modes of the bridge, being notably less than the modal variability caused by temperature effect.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471672
|
oai_dc
|
Decentralized civil structural control using real-time wireless sensing and embedded computing
|
Decentralized civil structural control using real-time wireless sensing and embedded computing
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yang Wang(Stanford University); R. Andrew Swartz(University of Michigan); Jerome P. Lynch(University of Michigan); Kincho H. Law(Stanford University); Kung-Chun Lu(National Taiwan University); Chin-Hsiung Loh(National Taiwan University)"
] |
Structural control technologies have attracted great interest from the earthquake engineering community over the last few decades as an effective method of reducing undesired structural responses. Traditional structural control systems employ large quantities of cables to connect structural sensors, actuators, and controllers into one integrated system. To reduce the high-costs associated with labor-intensive installations, wireless communication can serve as an alternative real-time communication link between the nodes of a control system. A prototype wireless structural sensing and control system has been physically implemented and its performance verified in large-scale shake table tests. This paper introduces the design of this prototype system and investigates the feasibility of employing decentralized and partially decentralized control strategies to mitigate the challenge of communication latencies associated with wireless sensor networks. Closed-loop feedback control algorithms are embedded within the wireless sensor prototypes allowing them to serve as controllers in the control system. To validate the embedment of control algorithms, a 3-story half-scale steel structure is employed with magnetorheological (MR) dampers installed on each floor. Both numerical simulation and experimental results show that decentralized control solutions can be very effective in attaining the optimal performance of the wireless control system.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471682
|
oai_dc
|
Parametric density concept for long-range pipeline health monitoring
|
Parametric density concept for long-range pipeline health monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"나원배(부경대학교); 윤한삼(부경대학교)"
] |
Parametric density concept is proposed for a long-range pipeline health monitoring. This concept is designed to obtain the attenuation of ultrasonic guided waves propagating in underwater pipelines without complicated calculation of attenuation dispersion curves. For the study, three different pipe materials such as aluminum, cast iron, and steel are considered, ten different transporting fluids are assumed, and four different geometric pipe dimensions are adopted. It is shown that the attenuation values based on the parametric density concept reasonably match with the attenuation values obtained from dispersion curves; hence, its efficiency is proved. With this concept, field engineers or inspectors associated with long-range pipeline health monitoring would take the advantage of easier capturing wave attenuation value, which is a critical variable to decide sensor location or sensors interval.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471646
|
oai_dc
|
Damage assessment of shear buildings by synchronous estimation of stiffness and damping using measured acceleration
|
Damage assessment of shear buildings by synchronous estimation of stiffness and damping using measured acceleration
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"신수봉(인하대학교); Seong Ho Oh(Dong-A University)"
] |
Nonlinear time-domain system identification (SI) algorithm is proposed to assess damage in a shear building by synchronously estimating time-varying stiffness and damping parameters using measured acceleration data. Mass properties have been assumed as the a priori known information. Viscous damping was utilized for the current research. To chase possible nonlinear dynamic behavior under severe vibration, an incremental governing equation of vibrational motion has been utilized. Stiffness and damping parameters are estimated at each time step by minimizing the response error between measured and computed acceleration increments at the measured degrees-of-freedom. To solve a nonlinear constrained optimization problem for optimal structural parameters, sensitivities of acceleration increment were formulated with respect to stiffness and damping parameters, respectively. Incremental state vectors of vibrational motion were computed numerically by Newmark-b method. No model is pre-defined in the proposed algorithm for recovering the nonlinear response. A time-window scheme together with Monte Carlo iterations was utilized to estimate parameters with noise polluted sparse measured acceleration. A moving average scheme was applied to estimate the time-varying trend of structural parameters in all the examples. To examine the proposed SI algorithm, simulation studies were carried out intensively with sample shear buildings under earthquake excitations. In addition, the algorithm was applied to assess damage with laboratory test data obtained from free vibration on a three-story shear building model.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471656
|
oai_dc
|
Structural performance evaluation of a steel-plate girder bridge using ambient acceleration measurements
|
Structural performance evaluation of a steel-plate girder bridge using ambient acceleration measurements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jin-Hak Yi(Korea Ocean Research and Development Institute); 조수진(KAIST); 구기영(KAIST); 윤정방(한국과학기술원); 김정태(부경대학교); Chang-Geun Lee(Korea Highway Corporation); Won-Tae Lee(Korea Highway Corporation)"
] |
The load carrying capacity of a bridge needs to be properly assessed to operate the bridge safely and maintain it efficiently. For the evaluation of load carrying capacity considering the current state of a bridge, static and quasi-static loading tests with weight-controlled heavy trucks have been conventionally utilized. In these tests, the deflection (or strain) of the structural members loaded by the controlled vehicles are measured and analyzed. Using the measured data, deflection (or strain) correction factor and impact correction factor are calculated. These correction factors are used in the enhancement of the load carrying capacity of a bridge, reflecting the real state of a bridge. However, full or partial control of the traffic during the tests and difficulties during the installment of displacement transducers or strain gauges may cause not only inconvenience to the traffic but also the increase of the logistics cost and time. To overcome these difficulties, an alternative method is proposed using an excited response part of full measured ambient acceleration data by ordinary traffic on a bridge without traffic control. Based on the modal properties extracted from the ambient vibration data, the initial finite element (FE) model of a bridge can be updated to represent the current real state of a bridge. Using the updated FE model, the deflection of a bridge akin to the real value can be easily obtained without measuring the real deflection. Impact factors are obtained from pseudo-deflection, which is obtained by double-integration of the acceleration data with removal of the linear components on the acceleration data. For validation, a series of tests were carried out on a steel plate-girder bridge of an expressway in Korea in four different seasons, and the evaluated load carrying capacities of the bridge by the proposed method are compared with the result obtained by the conventional load test method.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471685
|
oai_dc
|
Development and application of a vision-based displacement measurement system for structural health monitoring of civil structures
|
Development and application of a vision-based displacement measurement system for structural health monitoring of civil structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jong Jae Lee(KAIST); Yoshio Fukuda(University of California Irvine); Masanobu Shinozuka(University of Californai Irvine); 조수진(KAIST); 윤정방(한국과학기술원)"
] |
For structural health monitoring (SHM) of civil infrastructures, displacement is a good descriptor of the structural behavior under all the potential disturbances. However, it is not easy to measure displacement of civil infrastructures, since the conventional sensors need a reference point, and inaccessibility to the reference point is sometimes caused by the geographic conditions, such as a highway or river under a bridge, which makes installation of measuring devices time-consuming and costly, if not impossible. To resolve this issue, a vision-based real-time displacement measurement system using digital image processing techniques is developed. The effectiveness of the proposed system was verified by comparing the load carrying capacities of a steel-plate girder bridge obtained from the conventional sensor and the present system. Further, to simultaneously measure multiple points, a synchronized vision-based system is developed using master/slave system with wireless data communication. For the purpose of verification, the measured displacement by a synchronized vision-based system was compared with the data measured by conventional contact-type sensors, linear variable differential transformers (LVDT) from a laboratory test.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471125
|
oai_dc
|
Embedded smart GFRP reinforcements for monitoring reinforced concrete flexural components
|
Embedded smart GFRP reinforcements for monitoring reinforced concrete flexural components
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Anastasis V. Georgiades(Dalhousie University); Gobinda C. Saha(Dalhousie University); Alexander L. Kalamkarov(Dalhousie University); Srujan K. Rokkam(Dalhousie University); John P. Newhook(Dalhousie University); Krishna S. Challagulla(Dalhousie University)"
] |
The main objectives of this paper are to demonstrate the feasibility of using newly developed smart GFRP reinforcements to effectively monitor reinforced concrete beams subjected to flexural and creep loads, and to develop non-linear numerical models to predict the behavior of these beams. The smart glass fiber-reinforced polymer (GFRP) rebars are fabricated using a modified pultrusion process, which allows the simultaneous embeddement of Fabry-Perot fiber-optic sensors within them. Two beams are subjected to static and repeated loads (until failure), and a third one is under long-term investigation for assessment of its creep behavior. The accuracy and reliability of the strain readings from the embedded sensors are verified by comparison with corresponding readings from surface attached electrical strain gages. Nonlinear finite element modeling of the smart concrete beams is subsequently performed. These models are shown to be effective in predicting various parameters of interest such as crack patterns, failure loads, strains and stresses. The strain values computed by these numerical models agree well with corresponding readings from the embedded fiber-optic sensors.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471120
|
oai_dc
|
Versatile robotic platform for structural health monitoring and surveillance
|
Versatile robotic platform for structural health monitoring and surveillance
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Brian Esser(University of Vermont); Dryver R. Huston(University of Vermont)"
] |
Utilizing robotic based reconfigurable nodal structural health monitoring systems has many advantages over static or human positioned sensor systems. However, creating a robot capable of traversing a variety of civil infrastructures is a difficult task, as these structures each have unique features and characteristics posing a variety of challenges to the robot design. This paper outlines the design and implementation of a novel robotic platform for deployment on ferromagnetic structures as an enabling structural health monitoring technology. The key feature of this design is the utilization of an attachment device which is an advancement of the common magnetic base found in the machine tool industry. By mechanizing this switchable magnetic circuit and redesigning it for light weight and compactness, it becomes an extremely efficient and robust means of attachment for use in various robotic and structural health monitoring applications. The ability to engage and disengage the magnet as needed, the very low power required to do so, the variety of applicable geometric configurations, and the ability to hold indefinitely once engaged make this device ideally suited for numerous robotic and distributed sensor network applications. Presented here are examples of the mechanized variable force magnets, as well as a prototype robot which has been successfully deployed on a large construction site. Also presented are other applications and future directions of this technology.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471122
|
oai_dc
|
Health monitoring of steel structures using impedance of thickness modes at PZT patches
|
Health monitoring of steel structures using impedance of thickness modes at PZT patches
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Seunghee Park(KAIST); 윤정방(한국과학기술원); Yongrae Roh(Kyungpook National University); Jong-Jae Lee(KAIST)"
] |
This paper presents the results of a feasibility study on an impedance-based damage detection technique using thickness modes of piezoelectric (PZT) patches for steel structures. It is newly proposed to analyze the changes of the impedances of the thickness modes (frequency range > 1 MHz) at the PZT based on its resonant frequency shifts rather than those of the lateral modes (frequency range > 20 kHz) at the PZT based on its root mean square (RMS) deviations, since the former gives more significant variations in the resonant frequency shifts of the signals for identifying localities of small damages under the same measurement condition. In this paper, firstly, a numerical analysis was performed to understand the basics of the NDE technique using the impedance using an idealized 1-D electro-mechanical model consisting of a steel plate and a PZT patch. Then, experimental studies were carried out on two kinds of structural members of steel. Comparisons have been made between the results of crack detections using the thickness and lateral modes of the PZT patches.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471127
|
oai_dc
|
Crack mapping in RC members using distributed coaxial cable crack sensors: modeling and application
|
Crack mapping in RC members using distributed coaxial cable crack sensors: modeling and application
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Gary Greene, Jr.(University of Missouri-Rolla); Abdeldjelil Belarbi(University of Missouri-Rolla); Genda Chen(University of Missouri-Rolla)"
] |
The paper presents a model to calculate reinforcement strain using measured crack width in members under applied tension, flexure, and/or shear stress. Crack mapping using a new type of distributed coaxial cable sensors for health monitoring of large-scale civil engineering infrastructure was recently proposed and developed by the authors. This paper shows the results and performance of such sensors mounted on near surface of two flexural beams and a large scale reinforced concrete box girder that was subjected to cyclic combined shear and torsion. The main objectives of this health monitoring study was to correlate the sensor response to strain in the member, and show that magnitude of the signal reflection coefficient is related to increases in applied load, repeated cycles, cracking, and reinforcement yielding. The effect of multiple adjacent cracks, and signal loss was also investigated. The results shown in this paper are an important step in using the sensors for crack mapping and determining reinforcement strain for in-situ structures.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471123
|
oai_dc
|
Applications of fiber optic sensors for structural health monitoring
|
Applications of fiber optic sensors for structural health monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"K. Kesavan(Tharamani); K. Ravisankar(Tharamani); S. Parivallal(Tharamani); P. Sreeshylam(Tharamani)"
] |
Large and complex structures are being built now-a-days and, they are required to be functional even under extreme loading and environmental conditions. In order to meet the safety and maintenance demands, there is a need to build sensors integrated structural system, which can sense and provide necessary information about the structural response to complex loading and environment. Sophisticated tools have been developed for the design and construction of civil engineering structures. However, very little has been accomplished in the area of monitoring and rehabilitation. The employment of appropriate sensor is therefore crucial, and efforts must be directed towards non-destructive testing techniques that remain functional throughout the life of the structure. Fiber optic sensors are emerging as a superior non-destructive tool for evaluating the health of civil engineering structures. Flexibility, small in size and corrosion resistance of optical fibers allow them to be directly embedded in concrete structures. The inherent advantages of fiber optic sensors over conventional sensors include high resolution, ability to work in difficult environment, immunity from electromagnetic interference, large band width of signal, low noise and high sensitivity. This paper brings out the potential and current status of technology of fiber optic sensors for civil engineering applications. The importance of employing fiber optic sensors for health monitoring of civil engineering structures has been highlighted. Details of laboratory studies carried out on fiber optic strain sensors to assess their suitability for civil engineering applications are also covered.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471142
|
oai_dc
|
Bi-spectrum for identifying crack and misalignment in shaft of a rotating machine
|
Bi-spectrum for identifying crack and misalignment in shaft of a rotating machine
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jyoti K. Sinha(Bhabha Atomic Research Centre)"
] |
Bi-spectrum is a tool in the signal processing for identification of non-linear dynamic behvaiour in systems, and well-known for stationary system where components are non-linearly interacting. Breathing of a crack during shaft rotation is also exhibits a non-linear behaviour. The crack is known to generate 2X (twice the machine RPM) and higher harmonics in addition to 1X component in the shaft response during its rotation. Misaligned shaft also shows similar such feature as a crack in a shaft. The bi-spectrum method has now been applied on a small rotating rig to observe its features. The bi-spectrum results are found to be encouraging to distinguish these faults based on few experiments conducted on a small rig. The results are presented here.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471140
|
oai_dc
|
Optimal placement and tuning of multiple tuned mass dampers for suppressing multi-mode structural response
|
Optimal placement and tuning of multiple tuned mass dampers for suppressing multi-mode structural response
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Pennung Warnitchai(Asian Institute of Technology); Nam Hoang(The University of Tokyo)"
] |
The optimal design of multiple tuned mass dampers (multiple TMD's) to suppress multi-mode structural response of beams and floor structures was investigated. A new method using a numerical optimizer, which can effectively handle a large number of design variables, was employed to search for both optimal placement and tuning of TMD's for these structures under wide-band loading. The first design problem considered was vibration control of a simple beam using 10 TMD's. The results confirmed that for structures with widely-spaced natural frequencies, multiple TMD's can be adequately designed by treating each structural vibration mode as an equivalent SDOF system. Next, the control of a beam structure with two closely-spaced natural frequencies was investigated. The results showed that the most effective multiple TMD's have their natural frequencies distributed over a range covering the two controlled structural frequencies and have low damping ratios. Moreover, a single TMD can also be made effective in controlling two modes with closely spaced frequencies by a newly identified control mechanism, but the effectiveness can be greatly impaired when the loading position changes. Finally, a realistic problem of a large floor structure with 5 closely spaced frequencies was presented. The acceleration responses at 5 positions on the floor excited by 3 wide-band forces were simultaneously suppressed using 10 TMD's. The obtained multiple TMD's were shown to be very effective and robust.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471143
|
oai_dc
|
Vibration control of mechanical systems using semi-active MR-damper
|
Vibration control of mechanical systems using semi-active MR-damper
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Dipak K. Maiti(Indian Institute of Technology); P.P. Shyju(Malnad College of Engineering); K. Vijayaraju(Aeronautical Development Agency)"
] |
The concept of structural vibration control is to absorb vibration energy of the structure by introducing auxiliary devices. Various types of structural vibration control theories and devices have been recently developed and introduced into mechanical systems. One of such devices is damper employing controllable fluids such as ElectroRheological (ER) or MagnetoRheological (MR) fluids. MagnetoRheological (MR) materials are suspensions of fine magnetizable ferromagnetic particles in a non-magnetic medium exhibiting controllable rheological behaviour in the presence of an applied magnetic field. This paper presents the modelling of an MR-fluid damper. The damper model is developed based on Newtonian shear flow and Bingham plastic shear flow models. The geometric parameters are varied to get the optimised damper characteristics. The numerical analysis is carried out to estimate the damping coefficient and damping force. The analytical results are compared with the experimental results. The results confirm that MR damper is one of the most promising new semi-active devices for structural vibration control.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471144
|
oai_dc
|
Evaluation of shear capacity of FRP reinforced concrete beams using artficial neural networks
|
Evaluation of shear capacity of FRP reinforced concrete beams using artficial neural networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Nehdi(The University of Western Ontario); H. El Chabib(The University of Western Ontario); A. Saïd(The University of Western Ontario)"
] |
To calculate the shear capacity of concrete beams reinforced with fibre-reinforced polymer (FRP), current shear design provisions use slightly modified versions of existing semi-empirical shear design equations that were primarily derived from experimental data generated on concrete beams having steel reinforcement. However, FRP materials have different mechanical properties and mode of failure than steel, and extending existing shear design equations for steel reinforced beams to cover concrete beams reinforced with FRP is questionable. This paper investigates the feasibility of using artificial neural networks (ANNs) to estimate the nominal shear capacity, Vn of concrete beams reinforced with FRP bars. Experimental data on 150 FRP-reinforced beams were retrieved from published literature. The resulting database was used to evaluate the validity of several existing shear design methods for FRP reinforced beams, namely the ACI 440-03, CSA S806-02, JSCE-97, and ISIS Canada-01. The database was also used to develop an ANN model to predict the shear capacity of FRP reinforced concrete beams. Results show that current guidelines are either inadequate or very conservative in estimating the shear strength of FRP reinforced concrete beams. Based on ANN predictions, modified equations are proposed for the shear design of FRP reinforced concrete beams and proved to be more accurate than existing equations.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471141
|
oai_dc
|
A critical comparison of reflectometry methods for location of wiring faults
|
A critical comparison of reflectometry methods for location of wiring faults
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Cynthia Furse(University of Utah); You Chung Chung(Daegu University); Chet Lo(University of Utah); Praveen Pendayala(University of Utah)"
] |
Aging wiring in buildings, aircraft and transportation systems, consumer products, industrial machinery, etc. is among the most significant potential causes of catastrophic failure and maintenance cost in these structures. Smart wire health monitoring can therefore have a substantial impact on the overall health monitoring of the system. Reflectometry is commonly used for locating faults on wire and cables. This paper compares Time domain reflectometry (TDR), frequency domain reflectometry (FDR), mixed signal reflectometry (MSR), sequence time domain reflectometry (STDR), spread spectrum time domain reflectometry (SSTDR) and capacitance sensors in terms of their accuracy, convenience, cost, size, and ease of use. Advantages and limitations of each method are outlined and evaluated for several types of aircraft cables. The results in this paper can be extrapolated to other types of wire and cable systems.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001489824
|
oai_dc
|
Design of wireless sensor network and its application for structural health monitoring of cable-stayed bridge
|
Design of wireless sensor network and its application for structural health monitoring of cable-stayed bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"H.R. Lin(National Taiwan University); C.S. Chen(National Taiwan University); P.Y. Chen(National Taiwan University); F.J. Tsai(National Taiwan University); J.D. Huang(National Taiwan University); J.F. Li(National Taiwan University); C.T. Lin(National Taiwan University); W.J. Wu(National Taiwan University)"
] |
A low-cost wireless sensor network (WSN) solution with highly expandable super and simple nodes was developed. The super node was designed as a sensing unit as well as a receiving terminal with low energy consumption. The simple node was designed to serve as a cheaper alternative for large-scale deployment. A 12-bit ADC inputs and DAC outputs were reserved for sensor boards to ease the sensing integration. Vibration and thermal field tests of the Chi-Lu Bridge were conducted to evaluate the WSN뭩 performance. Integral acceleration, temperature and tilt sensing modules were constructed to simplify the task of long-term environmental monitoring on this bridge, while a star topology was used to avoid collisions and reduce power consumption. We showed that, given sufficient power and additional power amplifier, the WSN can successfully be active for more than 7 days and satisfy the half bridge 120-meter transmission requirement. The time and frequency responses of cables shocked by external force and temperature variations around cables in one day were recorded and analyzed. Finally, guidelines on power characterization of the WSN platform and selection of acceleration sensors for structural health monitoring applications were given.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001489820
|
oai_dc
|
Nonlinear dynamic response and its control of rubber components with piezoelectric patches/layers using finite element method
|
Nonlinear dynamic response and its control of rubber components with piezoelectric patches/layers using finite element method
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M.C. Manna(Bengal Engineering and Science University); R. Bhattacharyya(Indian Institute of Technology); A.H. Sheikh(University of Adelaide)"
] |
Idea of using piezoelectric materials with flexible structures made of rubber-like materials is quite novel. In this study a non-linear finite element model based on updated Lagrangian (UL) approach has been developed for dynamic response and its control of rubber-elastic material with surface-bonded PVDF patches/layers. A compressible stain energy density function has been used for the modeling of the rubber component. The results obtained are compared with available analytical solutions and other published results in some cases. Some results are reported as new results which will be useful for future references since the number of published results is not sufficient.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001489822
|
oai_dc
|
Assessment of velocity-acceleration feedback in optimal control of smart piezoelectric beams
|
Assessment of velocity-acceleration feedback in optimal control of smart piezoelectric beams
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S.B. Beheshti-Aval(Khajeh Nasir Toosi University of Technology (KNTU)); M. Lezgy-Nazargah(Khajeh Nasir Toosi University of Technology (KNTU))"
] |
Most of studies on control of beams containing piezoelectric sensors and actuators have been based on linear quadratic regulator (LQR) with state feedback or output feedback law. The aim of this study is to develop velocity-acceleration feedback law in the optimal control of smart piezoelectric beams. A new controller which is an optimal control system with velocity-acceleration feedback is presented. In finite element modeling of the beam, the variation of mechanical displacement through the thickness is modeled by a sinus model that ensures inter-laminar continuity of shear stress at the layer interfaces as well as the boundary conditions on the upper and lower surfaces of the beam. In addition to mechanical degrees of freedom, one electric potential degree of freedom is considered for each piezoelectric element layer. The efficiency of this control strategy is evaluated by applying to an aluminum cantilever beam under different loading conditions. Numerical simulations show that this new control scheme is almost as efficient as an optimal control system with state feedback. However, inclusion of the acceleration in the control algorithm increases practical value of a system due to easier and more accurate measurement of accelerations.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001489821
|
oai_dc
|
Effect of boundary conditions on modal parameters of the Run Yang Suspension Bridge
|
Effect of boundary conditions on modal parameters of the Run Yang Suspension Bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zhijun Li(Southeast University); Aiqun Li(Southeast University); Jian Zhang(National University of Singapore)"
] |
Changes in temperature, loads and boundary conditions may have effects on the dynamic properties of large civil structures. Taking the Run Yang Suspension Bridge as an example, modal properties obtained from ambient vibration tests and from the structural health monitoring system of the bridge are used to identify and evaluate the modal parameter variability. Comparisons of these modal parameters reveal that several low-order modes experience a significant change in frequency from the completion of the bridge to its operation. However, the correlation analysis between measured modal parameters and the temperature shows that temperature has a slight influence on the low-order modal frequencies. Therefore, this paper focuses on the effects of the boundary conditions on the dynamic behaviors of the suspension bridge. An analytical model is proposed to perform a sensitivity analysis on modal parameters of the bridge concerning the stiffness of expansion joints located at two ends of bridge girders. It is concluded that the boundary conditions have a significant influence on the low-order modal parameters of the suspension bridge. In addition, the influence of vehicle load on modal parameters is also investigated based on the proposed model.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001489830
|
oai_dc
|
Exact analyses for two kinds of piezoelectric hollow cylinders with graded properties
|
Exact analyses for two kinds of piezoelectric hollow cylinders with graded properties
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Taotao Zhang(Beihang University); Zhifei Shi(Beijing Jiaotong University)"
] |
Based on the theory of piezo-elasticity, the paper obtains the exact solutions of functionally graded piezoelectric hollow cylinders with different piezoelectric parameter g31. Two kinds of piezoelectric hollow cylinders are considered herein. One is a multi-layered cylinder with different parameter g31 in different layers; the other is a continuously graded cylinder with arbitrarily variable g31. By using the Airy stress function method with plane strain assumptions, the exact solutions of the mechanic and electrical components of both cylinders are obtained when they are subjected to external voltage (actuator) and pressure (sensor), simultaneously. Furthermore, good agreement is achieved between the theoretical and numerical results, and useful conclusions are given.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001489826
|
oai_dc
|
Seismic response control of benchmark highway bridge using variable dampers
|
Seismic response control of benchmark highway bridge using variable dampers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S.N. Madhekar(Indian Institute of Technology Bombay); R.S. Jangid(Indian Institute of Technology Bombay)"
] |
The performance of variable dampers for seismic protection of the benchmark highway bridge (phase I) under six real earthquake ground motions is presented. A simplified lumped mass finite-element model of the 91/5 highway bridge in Southern California is used for the investigation. A variable damper, developed from magnetorheological (MR) damper is used as a semi-active control device and its effectiveness with friction force schemes is investigated. A velocity-dependent damping model of variable damper is used. The effects of friction damping of the variable damper on the seismic response of the bridge are examined by taking different values of friction force, step-coefficient and transitional velocity of the damper. The seismic responses with variable dampers are compared with the corresponding uncontrolled case, and controlled by alternate sample control strategies. The results of investigation clearly indicate that the base shear, base moment and mid-span displacement are substantially reduced. In particular, the reduction in the bearing displacement is quite significant. The friction and the two-step friction force schemes of variable damper are found to be quite effective in reducing the peak response quantities of the bridge to a level similar to or better than that of the sample passive, semi-active and active controllers.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471010
|
oai_dc
|
Simultaneous precision positioning and vibration suppression of reciprocating flexible manipulators
|
Simultaneous precision positioning and vibration suppression of reciprocating flexible manipulators
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kougen Ma(University of Hawaii at Manoa); Mehrdad N. Ghasemi-Nejhad(University of Hawaii at Manoa)"
] |
Simultaneous precision positioning and vibration suppression of a reciprocating flexible manipulator is investigated in this paper. The flexible manipulator is driven by a multifunctional active strut with fuzzy logic controllers. The multifunctional active strut is a combination of a motor assembly and a piezoelectric stack actuator to simultaneously provide precision positioning and wide frequency bandwidth vibration suppression capabilities. First, the multifunctional active strut and the flexible manipulator are introduced, and their dynamic models are derived. A control strategy is then proposed, which includes a position controller and a vibration controller to achieve simultaneous precision positioning and vibration suppression of the flexible manipulator. Next, fuzzy logic control approach is presented to design a fuzzy logic position controller and a fuzzy logic vibration controller. Finally, experiments are conducted for the fuzzy logic controllers and the experimental results are compared with those from a PID control scheme consisting of a PID position controller and a PID vibration control. The comparison indicates that the fuzzy logic controller can easily handle the non-linearity in the strut and provide higher position accuracy and better vibration reduction with less control power consumption.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471027
|
oai_dc
|
Development of smart transducer with embedded sensor for automatic process control of ultrasonic wire bonding
|
Development of smart transducer with embedded sensor for automatic process control of ultrasonic wire bonding
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Siu Wing Or(The Hong Kong Polytechnic University); Helen Lai Wa Chan(The Hong Kong Polytechnic University); Peter Chou Kee Liu(ASM Assembly Automation Ltd.)"
] |
A ring-shaped lead zirconate titanate (PZT) piezoceramic sensor has been integrated with the Langevin-type piezoceramic driver of an ultrasonic wire-bonding transducer to form a smart transducer for in-situ measurement of three essential bonding parameters: namely, impact force, ultrasonic amplitude and bond time. This sensor has an inner diameter, an outer diameter and a thickness of 12.7 mm, 5.1 mm and 0.6 mm, respectively. It has a specifically designed electrode pattern on the two major surfaces perpendicular to its thickness along which polarization is induced. The process-test results have indicated that the sensor not only is sensitive to excessive impact forces exerted on the devices to be bonded but also can track changes in the ultrasonic amplitude proficiently during bonding. Good correlation between the sensor outputs and the bond quality has been established. This smart transducer has good potential to be used in automatic process-control systems for ultrasonic wire bonding.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471012
|
oai_dc
|
Structural damage localization using spatial wavelet packet signature
|
Structural damage localization using spatial wavelet packet signature
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"C.C. Chang(Hong Kong University of Science and Technology); Z. Sun(Hong Kong University of Science and Technology)"
] |
In this study, a wavelet packet based method is proposed for identifying damage occurrence and damage location for beam-like structures. This method assumes that the displacement or the acceleration response time histories at various locations along a beam-like structure both before and after damage are available for damage assessment. These responses are processed through a proper level of wavelet packet decomposition. The wavelet packet signature (WPS) that consists of wavelet packet component signal energies is calculated. The change of the WPS curvature between the baseline state and the current state is then used to identify the locations of possible damage in the structure. Two numerical studies, one on a 15-storey shear-beam building frame and another on a simply-supported steel beam, and an experimental study on a simply-supported reinforced concrete beam are performed to validate the proposed method. Results show the WPS curvature change can be used to locate both single and sparsely-distributed multiple damages that exist in the structure. Also the accuracy of assessment does not seem to be affected by the presence of 20-15dB measurement noise. One advantage of the proposed method is that it does not require any mathematical model for the structure being monitored and hence can potentially be used for practical application.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471039
|
oai_dc
|
Frontiers in sensors and sensing systems
|
Frontiers in sensors and sensing systems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Steven D. Glaser(University of California); Rahmat A. Shoureshi(University of Denver); David Pescovitz(Science Writer)"
] |
토목공학
| null |
kci_detailed_000092.xml
|
||||
ART001471036
|
oai_dc
|
Modal identification and model updating of a reinforced concrete bridge
|
Modal identification and model updating of a reinforced concrete bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S. El-Borgi(Tunisia Polytechnic School); S. Choura(Tunisia Polytechnic School); C. Ventura(University of British Columbia); M. Baccouch(Tunisia Polytechnic School); F. Cherif(Tunisia Polytechnic School)"
] |
This paper summarizes the application of a rational methodology for the structural assessment of older reinforced concrete Tunisian bridges. This methodology is based on ambient vibration measurement of the bridge, identification of the structures modal signature and finite element model updating. The selected case study is the Boujnah bridge of the Tunis-Msaken Highway. This bridge is made of a continuous four-span simply supported reinforced concrete slab without girders resting on elastomeric bearings at each support. Ambient vibration tests were conducted on the bridge using a data acquisition system with nine force-balance accelerometers placed at selected locations of the bridge. The Enhanced Frequency Domain Decomposition technique was applied to extract the dynamic characteristics of the bridge. The finite element model was updated in order to obtain a reasonable correlation between experime ntal and numerical modal properties. For the model updating part of the study, the parameters selected for the updating process include the concrete modulus of elasticity, the elastic bearing stiffness and the foundation spring stiffnesses. The primary objective of the paper is to demonstrate the use of the Enhanced Frequency Domain Decomposition technique combined with model updating to provide data that could be used to assess the structural condition of the selected bridge. The application of the proposed methodology led to a relatively faithful linear elastic model of the bridge in its present condition.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471030
|
oai_dc
|
Conceptual design and preliminary characterization of serial array system of high-resolution MEMS accelerometers with embedded optical detection
|
Conceptual design and preliminary characterization of serial array system of high-resolution MEMS accelerometers with embedded optical detection
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Maximilian Perez(University of California); Andrei Shkel(University of California)"
] |
This paper introduces a technology for robust and low maintenance cost sensor network capable to detect accelerations below a micro-g in a wide frequency bandwidth (above 1,000 Hz). Sensor networks with such performance are critical for navigation, seismology, acoustic sensing, and for the health monitoring of civil structures. The approach is based on the fabrication of an array of high sensitivity accelerometers, each utilizing Fabry-Perot cavity with wavelength-dependent reflectivity to allow embedded optical detection and serialization. The unique feature of the approach is that no local power source is required for each individual sensor. Instead one global light source is used, providing an input optical signal which propagates through an optical fiber network from sensor-to-sensor. The information from each sensor is embedded onto the transmitted light as an intrinsic wavelength division multiplexed signal. This optical rainbow of data is then assessed providing real-time sensing information from each sensor node in the network. This paper introduces the Fabry-Perot based accelerometer and examines its critical features, including the effects of imperfections and resolution estimates. It then presents serialization techniques for the creation of systems of arrayed sensors and examines the effects of serialization on sensor response. Finally, a fabrication process is proposed to create test structures for the critical components of the device, which are dynamically characterized.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471008
|
oai_dc
|
Challenges and opportunities in the engineering of intelligent systems
|
Challenges and opportunities in the engineering of intelligent systems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Shi-Chi Liu(National Science Foundation); Masayoshi Tomizuka(National Science Foundation); A. Galip Ulsoy(National Science Foundation)"
] |
This paper describes the area of intelligent systems research as funded by the Civil and Mechanical Systems (CMS) Division of the National Science Foundation (NSF). With developments in computer science, information technology, sensing and control the design of typical machines and structures by civil and mechanical engineers is evolving toward intelligent systems that can sense, decide and act. This trend toward electromechanical
design is well-established in modern machines (e.g. vehicles, robots, disk drives) and often referred to as mechatronics. More recently intelligent systems design is becoming an important aspect of structures, such as
buildings and bridges. We briefly review recent developments in structural control, including the role that NSF has played in their development, and discuss on-going CMS activities in this area. In particular, we highlight the
interdisciplinary initiative on Sensors and Sensor Networks and the Network for Earthquake Engineering Simulation (NEES). NEES is a distributed cyberinfrastructure to support earthquake engineering research, and
provides the pioneering NEES grid computing environment for simulation, teleoperation, data collection and archiving, etc.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471749
|
oai_dc
|
Experimental verification of a distributed computing strategy for structural health monitoring
|
Experimental verification of a distributed computing strategy for structural health monitoring
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y. Gao(WSP Cantor Seinuk); B.F. Spencer, Jr.(University of Illinois at Urbana-Champaign)"
] |
A flexibility-based distributed computing strategy (DCS) for structural health monitoring (SHM) has recently been proposed which is suitable for implementation on a network of densely distributed smart sensors. This approach uses a hierarchical strategy in which adjacent smart sensors are grouped together to form sensor communities. A flexibility-based damage detection method is employed to evaluate the condition of the local elements within the communities by utilizing only locally measured information. The damage detection results in these communities are then communicated with the surrounding communities and sent back to a central station. Structural health monitoring can be done without relying on central data acquisition and processing. The main purpose of this paper is to experimentally verify this flexibility-based DCS approach using wired sensors; such verification is essential prior to implementation on a smart sensor platform. The damage locating vector method that forms foundation of the DCS approach is briefly reviewed, followed by an overview of the DCS approach. This flexibility-based approach is then experimentally verified employing a 5.6 m long three-dimensional truss structure. To simulate damage in the structure, the original truss members are replaced by ones with a reduced cross section. Both single and multiple damage scenarios are studied. Experimental results show that the DCS approach can successfully detect the damage at local elements using only locally measured information.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471723
|
oai_dc
|
A new hybrid vibration control methodology using a combination of magnetostrictive and hard damping alloys
|
A new hybrid vibration control methodology using a combination of magnetostrictive and hard damping alloys
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Vidyashankar R. Buravalla(GM India Technical Centre); Bishakh Bhattacharya(Indian Institute of Technology)"
] |
A new hybrid damping technique for vibration reduction in flexible structures, wherein a combination of layers of hard passive damping alloys and active (smart) magnetostrictive material is used to reduce vibrations, is proposed. While most conventional vibration control treatments are based exclusively on either passive or active based systems, this technique aims to combine the advantages of these systems and simultaneously, to overcome the inherent disadvantages in the individual systems. Two types of combined damping systems are idealized and studied here, viz., the Noninteractive system and the Interactive system. Frequency domain studies are carried out to investigate their performance. Finite element simulations using previously developed smart beam elements are carried out on typical metallic and laminated composite cantilever beams treated with hybrid damping. The influence of various parameters like excitation levels, frequency (mode) and control gain on the damping performance is investigated. It is shown that the proposed system could be used effectively to dampen the structural vibration over a wide frequency range. The interaction between the active and passive damping layers is brought out by a comparative study of the combined systems. Illustrative comparisons with only passive and only active damping schemes are also made. The influence and the mode dependence of control gain in a hybrid system is clearly illustrated. This study also demonstrates the significance and the exploitation of strain dependency of passive damping on the overall damping of the hybrid system. Further, the influence of the depthwise location of damping layers in laminated structures is also investigated.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471729
|
oai_dc
|
Identification of nonlinear elastic structures using empirical mode decomposition and nonlinear normal modes
|
Identification of nonlinear elastic structures using empirical mode decomposition and nonlinear normal modes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"C.W. Poon(Hong Kong University of Science and Technology); C.C. Chang(Hong Kong University of Science and Technology)"
] |
The empirical mode decomposition (EMD) method is well-known for its ability to decompose a multi-component signal into a set of intrinsic mode functions (IMFs). The method uses a sifting process in which local extrema of a signal are identified and followed by a spline fitting approximation for decomposition. This method provides an effective and robust approach for decomposing nonlinear and non-stationary signals. On the other hand, the IMF components do not automatically guarantee a well-defined physical meaning hence it is necessary to validate the IMF components carefully prior to any further processing and interpretation. In this paper, an attempt to use the EMD method to identify properties of nonlinear elastic multi-degree-of-freedom structures is explored. It is first shown that the IMF components of the displacement and velocity responses of a nonlinear elastic structure are numerically close to the nonlinear normal mode (NNM) responses obtained from two-dimensional invariant manifolds. The IMF components can then be used in the context of the NNM method to estimate the properties of the nonlinear elastic structure. A two-degree-of-freedom shear-beam building model is used as an example to illustrate the proposed technique. Numerical results show that combining the EMD and the NNM method provides a possible means for obtaining nonlinear properties in a structure.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471760
|
oai_dc
|
Performance evaluation of smart prefabricated concrete elements
|
Performance evaluation of smart prefabricated concrete elements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Daniele Zonta(University of Trento); Matteo Pozzi(University of Trento); Oreste S. Bursi(University of Trento)"
] |
This paper deals with the development of an innovative distributed construction system based on smart prefabricated concrete elements for the real-time condition assessment of civil infrastructure. So far, two reduced-scale prototypes have been produced, each consisting of a 0.2?.3?.6 m RC beam specifically designed for permanent instrumentation with 8 long-gauge Fiber Optic Sensors (FOS) at the lower edge. The sensing system is Fiber Bragg Grating (FBG)-based and can measure finite displacements both static and dynamic with a sample frequency of 625 Hz per channel. The performance of the system underwent validation in the laboratory. The scope of the experiment was to correlate changes in the dynamic response of the beams with different damage scenarios, using a direct modal strain approach. Each specimen was dynamically characterized in the undamaged state and in various damage conditions, simulating different cracking levels and recurrent deterioration scenarios, including cover spalling and corrosion of the reinforcement. The location and the extent of damage are evaluated by calculating damage indices which take account of changes in frequency and in strain-mode-shapes. The outcomes of the experiment demonstrate how the damage distribution detected by the system is fully compatible with the damage extent appraised by inspection.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471784
|
oai_dc
|
Bio-inspired autonomous engineered systems
|
Bio-inspired autonomous engineered systems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Masayoshi Tomizuka(University of California Berkeley); Lawrence A. Bergman(University of Illinois at Urbana-Champaign); Ben Shapiro(University of Maryland); Rahmat Shoureshi(University of Denver); B.F. Spencer, Jr.(University of Illinois at Urbana-Champaign); Minoru Taya(University of Washington)"
] |
토목공학
| null |
kci_detailed_000092.xml
|
||||
ART001471742
|
oai_dc
|
A pre-stack migration method for damage identification in composite structures
|
A pre-stack migration method for damage identification in composite structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"L. Zhou(Nanjing University of Aeronautics and Astronautics); F.G. Yuan(North Carolina State University); W.J. Meng(Nanjing University of Aeronautics and Astronautics)"
] |
In this paper a damage imaging technique using pre-stack migration is developed using Lamb (guided) wave propagation in composite structures for imaging multi damages by both numerical simulations and experimental studies. In particular, the paper focuses on the experimental study using a finite number of sensors for future practical applications. A composite laminate with a surface-mounted linear piezoelectric ceramic (PZT) disk array is illustrated as an example. Two types of damages, one straight-crack damage and two simulated circular-shaped delamination damage, have been studied. First, Mindlin plate theory is used to model Lamb waves propagating in laminates. The group velocities of flexural waves in the composite laminate are also derived from dispersion relations and validated by experiments. Then the pre-stack migration technique is performed by using a two-dimensional explicit finite difference algorithm to back-propagate the scattered energy to the damages and damages are imaged together with the excitation-time imaging conditions. Stacking these images together deduces the resulting image of damages. Both simulations and experimental results show that the pre-stack migration method is a promising method for damage identification in composite structures.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471557
|
oai_dc
|
A reliability-based criterion of structural performance for structures with linear damping
|
A reliability-based criterion of structural performance for structures with linear damping
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Agnessa Kovaleva(Russian Academy of Sciences)"
] |
The reliability analysis of structures subjected to stochastic loading involves evaluation of time and probability of the system residence in a reference domain. In this paper, we derive an asymptotic estimate of exit time for multi-degrees-of-freedom structural systems. The system dynamics is governed by the Lagrangian equations with linear dissipation and fast additive noise. The logarithmic asymptotic of exit time is found explicitly as a sum of two terms dependent on kinetic and potential energy of the system, respectively. As an example, we estimate exit time and an associated structural performance for a rocking structure.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471553
|
oai_dc
|
Analysis of layered bases-foundations models under seismic actions
|
Analysis of layered bases-foundations models under seismic actions
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"L.A. Aghalovyan(National Academy of Sciences); A.V. Sahakyan(National Academy of Sciences); M.L. Aghalovyan(National Academy of Sciences)"
] |
The paper considers the dynamic behaviour of the two-layered and multi-layered plate packets under dynamic (seismic) loading. These models correspond to the base-foundation packet structures. The analysis of the various models, including the models of contact between the layers, is derived on the base of the precise solutions of elasticity theory equations. It is shown that the application of the seismoisolator or, in general, less rigid materials between the base and the foundation brings to reduction of the natural frequencies of free vibrations of the packet base-foundation, as well as to the significant reduction of the negative seismic effect on the structures.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471567
|
oai_dc
|
An approach for modelling fracture of shape memory alloy parts
|
An approach for modelling fracture of shape memory alloy parts
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Margarita E. Evard(Saint-Petersburg State University); Alexander E. Volkov(Saint-Petersburg State University); Olga V. Bobeleva(Saint-Petersburg State University)"
] |
Equations describing deformation defects, damage accumulation, and fracture condition have been suggested. Analytical and numerical solutions have been obtained for defects produced by a shear in a fixed direction. Under cyclic loading the number of cycles to failure well fits the empirical Koffin-Manson law. The developed model is expanded to the case of the micro-plastic deformation, which accompanies martensite accommodation in shape memory alloys. Damage of a shape memory specimen has been calculated for two regimes of loading: a constant stress and cyclic variation of temperature across the interval of martensitic transformations, and at a constant temperature corresponding to the pseudoelastic state and cyclic variation of stress. The obtained results are in a good qualitative agreement with available experimental data.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471564
|
oai_dc
|
Retrofit of a hospital through strength reduction and enhanced damping
|
Retrofit of a hospital through strength reduction and enhanced damping
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Stefania Viti(University of Florence); Gian Paolo Cimellaro(University at Buffalo); Andrei M. Reinhorn(University at Buffalo)"
] |
A procedure to retrofit existing essential facilities subjected to seismic excitation is proposed. The main features of this procedure are to reduce maximum acceleration and associated forces in buildings subjected to seismic excitation by reducing their strength (weakening). The weakening retrofit, which is an opposite strategy to strengthening, is particularly suitable for buildings having overstressed components and foundation supports or having weak brittle components. However, by weakening the structure large deformations are expected. Supplemental damping devices however can control the deformations within desirable limits. The structure retrofitted with this strategy will have, therefore, a reduction in the acceleration response and a reduction in the deformations, depending on the amount of additional damping introduced in the structure. An illustration of the above strategy is presented here through an evaluation of the inelastic response of the structure through a nonlinear dynamic analysis. The results are compared with different retrofit techniques. A parametric analysis has also been carried out to evaluate the effectiveness of the retrofitting method using different combination of the performance thresholds in accelerations and displacements through fragility analysis.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471562
|
oai_dc
|
Seismic isolation of hospital buildings
|
Seismic isolation of hospital buildings
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Liudmila Soldatova(Kyrgyz State University of Construction); Sulaiman Jumukov(Kyrgyz State University of Construction)"
] |
This paper illustrates an analytical investigation of the vibration parameters of buildings on sliding seismic isolation bearings with elastic limiters of the relative displacement. The installation scheme of sliding bearings and elastic limiters for the separate unit of a 4 storey hospital building with brick walls is designed. The analysis of the vibrations of the hospital building is conducted for harmonic base excitation.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471559
|
oai_dc
|
Testing of rubber bearings for the dynamic damper of seismic isolated buildings
|
Testing of rubber bearings for the dynamic damper of seismic isolated buildings
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mikayel Melkumyan(The American University of Armenia); Alexander Hakobyan(The American University of Armenia)"
] |
The paper describes the testing facilities and the methodology on testing of laminated rubber bearings envisaged for application in the system of Dynamic Damper (DD) of seismic isolated buildings, as well as the obtained results. For the first time in Armenia laminated rubber bearings were tested simultaneously under the action of horizontal shear force and vertical tension force. The test results have proven the possibility of using rubber bearings as elements subjected to tension due to action of the mass of DD. Also it was confirmed that the suggested structural concept of DD for reducing the displacements and shear forces of seismic isolation systems will have reliable behavior during the design level earthquakes.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001471555
|
oai_dc
|
Rehabilitation of hospital buildings using passive control systems
|
Rehabilitation of hospital buildings using passive control systems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"C.A. Syrmakezis(National Technical University of Athens); O.A. Mavrouli(National Technical University of Athens); A.K. Antonopoulos(National Technical University of Athens)"
] |
In the case of hospital buildings, where seismic design requirements are very high, existing structures and especially those attacked by past earthquakes, appear, often, unable to fulfil the necessary safety prerequisites. In this paper, the retrofitting of hospital buildings is investigated, using alternative methods of repair and strengthening. Analysis of an existing hospital building in Patras, Greece, is performed. The load-bearing system is a reinforced concrete system. Two solutions are proposed: strengthening using concrete jackets around column and beam elements and application of viscoelastic dampers for the increase of the stability of the structure. Adequate finite element models are constructed for each case and conclusions are drawn on the efficiency of each rehabilitation method.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001497192
|
oai_dc
|
Coupling shape-memory alloy and embedded informatics toward a metallic self-healing material
|
Coupling shape-memory alloy and embedded informatics toward a metallic self-healing material
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lucia Faravelli(University of Pavia); Alessandro Marzi(University of Pavia)"
] |
This paper investigates the possibility of a strategy for an automatic full recover of a structural component undergoing loading-unloading (fatigue) cycles: full recover means here that no replacement is required at the end of the mission. The goal is to obtain a material capable of self healing earlier before the damage becomes irreversible. Attention is focused on metallic materials, and in particular on shape memory alloys, for which the recovering policy just relies on thermal treatments. The results of several fatigue tests are first reported to acquire a deep understanding of the physical process. Then, for cycles of constant amplitude, the self-healing objective is achieved by mounting, on the structural component of interest, a suitable microcontroller. Its input, from suitable sensors, covers the current stress and strain in the alloy. The microcontroller elaborates from the input the value of a decisional parameter and activates the thermal process when a threshold is overcome.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001497195
|
oai_dc
|
Comparison of various structural damage tracking techniques based on experimental data
|
Comparison of various structural damage tracking techniques based on experimental data
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hongwei Huang(Tongji University); Jann N. Yang(University of California); Li Zhou(Nanjing University of Aeronautics and Astronautics)"
] |
An early detection of structural damages is critical for the decision making of repair and replacement maintenance in order to guarantee a specified structural reliability. Consequently, the structural damage detection, based on vibration data measured from the structural health monitoring (SHM) system, has received considerable attention recently. The traditional time-domain analysis techniques, such as the least square estimation (LSE) method and the extended Kalman filter (EKF) approach, require that all the external excitations (inputs) be available, which may not be the case for some SHM systems. Recently, these two approaches have been extended to cover the general case where some of the external excitations (inputs) are not measured, referred to as the adaptive LSE with unknown inputs (ALSE-UI) and the adaptive EKF with unknown inputs (AEKF-UI). Also, new analysis methods, referred to as the adaptive sequential non-linear least-square estimation with unknown inputs and unknown outputs (ASNLSE-UI-UO) and the adaptive quadratic sum-squares error with unknown inputs (AQSSE-UI), have been proposed for the damage tracking of structures when some of the acceleration responses are not measured and the external excitations are not available. In this paper, these newly proposed analysis methods will be compared in terms of accuracy, convergence and efficiency, for damage identification of structures based on experimental data obtained through a series of laboratory tests using a scaled 3-story building model with white noise excitations. The capability of the ALSE-UI, AEKF-UI, ASNLSE-UI-UO and AQSSE-UI approaches in tracking the structural damages will be demonstrated and compared.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001497187
|
oai_dc
|
Locating the damaged storey of a building using distance measures of low-order AR models
|
Locating the damaged storey of a building using distance measures of low-order AR models
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zhenhua Xing(Keio University); Akira Mita(Keio University)"
] |
The key to detecting damage to civil engineering structures is to find an effective damage indicator. The damage indicator should promptly reveal the location of the damage and accurately identify the state of the structure. We propose to use the distance measures of low-order AR models as a novel damage indicator. The AR model has been applied to parameterize dynamical responses, typically the acceleration response. The premise of this approach is that the distance between the models, fitting the dynamical responses from damaged and undamaged structures, may be correlated with the information about the damage, including its location and severity. Distance measures have been widely used in speech recognition. However, they have rarely been applied to civil engineering structures. This research attempts to improve on the distance measures that have been studied so far. The effect of varying the data length, number of parameters, and other factors was carefully studied.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001497189
|
oai_dc
|
An integrated visual-inertial technique for structural displacement and velocity measurement
|
An integrated visual-inertial technique for structural displacement and velocity measurement
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"C.C. Chang(Hong Kong University of Science and Technology); X.H. Xiao(Hong Kong University of Science and Technology)"
] |
Measuring displacement response for civil structures is very important for assessing their performance, safety and integrity. Recently, video-based techniques that utilize low-cost high-resolution digital cameras have been developed for such an application. These techniques however have relatively low sampling frequency and the results are usually contaminated with noises. In this study, an integrated visual-inertial measurement method that combines a monocular videogrammetric displacement measurement technique and a collocated accelerometer is proposed for displacement and velocity measurement of civil engineering structures. The monocular videogrammetric technique extracts three-dimensional translation and rotation of a planar target from an image sequence recorded by one camera. The obtained displacement is then fused with acceleration measured from a collocated accelerometer using a multi-rate Kalman filter with smoothing technique. This data fusion not only can improve the accuracy and the frequency bandwidth of displacement measurement but also provide estimate for velocity. The proposed measurement technique is illustrated by a shake table test and a pedestrian bridge test. Results show that the fusion of displacement and acceleration can mitigate their respective limitations and produce more accurate displacement and velocity responses with a broader frequency bandwidth.
|
토목공학
| null |
kci_detailed_000092.xml
|
|||
ART001497188
|
oai_dc
|
Design and evaluation of a distributed TDR moisture sensor
|
Design and evaluation of a distributed TDR moisture sensor
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Bin Zhang(Case Western Reserve University); Xinbao Yu(Case Western Reserve University); Xiong Yu(Case Western Reserve University)"
] |
This paper describes the development and evaluation of an innovative TDR distributed moisture sensor. This sensor features advantages of being responsive to the spatial variations of the soil moisture content. The geometry design of the sensor makes it rugged for field installation. Good linear calibration is obtained between the sensor measured dielectric constant and soil physical properties. Simulations by the finite element method (FEM) are conducted to assist the design of this sensor and to determine the effective sampling range. Compared with conventional types of moisture sensor, which only makes point measurement, this sensor possesses distributed moisture sensing capability. This new sensor is not only easy to install, but also measures moisture distribution with much lower cost. This new sensor holds promise to significantly improve the current field instruments. It will be a useful tool to help study the influence of a variety of moisture-related phenomena on infrastructure performance.
|
토목공학
| null |
kci_detailed_000093.xml
|
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