Structural health monitoring

About: Structural health monitoring is a research topic. Over the lifetime, 11727 publications have been published within this topic receiving 186231 citations.

Optimal Placement of Piezoelectric Actuators and Sensors for Detecting Damage in Plate Structures

Abstract: We propose a novel approach for optimal actuator and sensor placement for active sensing-based structural health monitoring. Of particular interest is the optimization of actuator—sensor arrays making use of ultrasonic wave propagation for detecting damage in thin plate-like structures. Using a detection theory framework, we establish the optimum configuration as the one that minimizes Bayes risk. The detector incorporates a statistical model of the active sensing process that accounts for both reflection and attenuation features, implements pulse-echo and pitch-catch actuation schemes, and takes into account line-of-site. The optimization space was searched using a genetic algorithm with a time-varying mutation rate. For verification, we densely instrumented a concave-shaped plate and applied artificial, reversible damage to a large number of randomly generated locations, acquiring active sensing data for each location. We then used the algorithm to predict optimal subsets of the dense array. The predict...

Identification and monitoring of bridge health from ambient vibration data

Abstract: Many bridges in Taiwan have been in use from the period that Taiwan was governed by the Japanese, over 50 years ago, which is the average ultimate usable lifetime of such structures. Three-quarters of the bridges on major highways have been in use for more than 20 years and numerous bridges on country roads have also been in use for more than 20 years. In other words, most of the bridges in Taiwan are aging and may require repair or replacement. Ambient vibration tests are utilized to measure the response of old bridges, which are difficult to equip with accelerometers. The Fourier transform method is traditionally used to gain important information about ambient vibration records. However, the development of information technology over the last 20 years has meant that there are more kinds of signal management technologies, including the wavelet and Hilbert—Huang transform (HHT) methods. In this study we investigate the characteristics of aging bridges by comparison with their structural properties. We analyze their ambient vibration, and discuss the possible influence of the frequency function. Long-term environmental impacts create many structural problems, but with traditional methods examination of bridge health is difficult. Therefore, in our HHT management system, we examine destroyed bridges. The characteristics and behavior of bridges subjected to random loading can be understood by analysis with the random decrement technique and the frequency response function method.

A Review of Passive Wireless Sensors for Structural Health Monitoring

Abstract: Wireless sensors for Structural Health Monitoring (SHM) is an emerging new technology that promises to overcome many disadvantages pertinent to conventional, wired sensors. The broad field of SHM has experienced significant growth over the past two decades, with several notable developments in the area of sensors such as piezoelectric sensors and optical fibre sensors. Although significant improvements have been made on damage monitoring techniques using these smart sensors, wiring remains a significant challenge to the practical implementation of these technologies. Wireless SHM has recently attracted the attention of researchers towards un-powered and more effective passive wireless sensors. This article presents a review of some of the underlying technologies in the field of wireless sensors for SHM - with a focus on the research progress towards the development of simple, powerless, yet effective and robust wireless damage detection sensors. This review examines the development of passive wireless sensors in two different categories: (1) use of oscillating circuits with the help of inductors, capacitors and resistors for damage detection; and (2) use of antennas, Radio Frequency Identification (RFID) tags and metamaterial resonators as strain sensors for wireless damage monitoring. An assessment of these electromagnetic techniques is presented and the key issues involved in their respective design configurations are discussed.

Long-term condition assessment of suspenders under traffic loads based on structural monitoring system : application to the Tsing Ma Bridge

Abstract: SUMMARY Structural health monitoring (SHM) system provides an efficient way to the diagnosis and prognosis of critical and large-scale civil infrastructures like long-span bridges. This paper presents a long-term condition assessment approach of suspenders in a cable-suspension bridge under in-service traffic loads based on structural monitoring technique. The traffic loads identified from a monitoring system, including both highway and railway traffic loads, and the finite element model of the bridge are employed to determine the axial force response of the suspender. The stochastic axial force response in the suspender is described by a filtered Poisson process, through which the maximum value distribution of axial forces in its design reference period can be derived using the Poisson Process theory. In this paper, the long-term deterioration process of steel wires in the suspender considers simultaneously the uniform and pitting corrosion and the corrosion fatigue induced by both cyclic loading and environmental attack. Such a stochastic and coupled corrosion fatigue process of steel wires is simulated using the Monte Carlo method, and the time-variant conditions of the suspender are subsequently assessed in a probabilistic way, such as crack depth, number of broken wires, ultimate strength, etc. In particular, two load conditions—the train loads alone and the combination of train load and road traffic load—are examined within this procedure in order to investigate their respective effects on the deterioration. By employing first-order reliability method, the reliability indexes of the suspender under the traffic loads are further estimated in terms of the safety under the extreme traffic load distribution in the design reference period and the serviceability specified in the design specification. The discussions of the life-cycle reliability indexes of the suspender provide guidance to the future decision making related to maintenance and replacement of suspenders, and it may also shed light on the long-term condition assessment of other structural members. Copyright © 2010 John Wiley & Sons, Ltd.