Wireless Sensor Networks for Structural Health Monitoring: A Multi-Scale Approach

Abstract

Given the present burdens associated with inspection and maintenance of Civil Infrastructure, the development of effective, automated damage diagnosis techniques, including the sensor technologies that support them, has become a major research need. While recent developments in wireless sensor networks have demonstrated their potential to provide continuous structural response data to quantitatively assess structural health, many important issues including network lifetime and stability, damage detection reliability, and trade-offs in model order to balance computational capabilities must be realistically addressed. Only then can wireless embedded sensor networks become a practical tool for Structural Health Monitoring of large, complex Civil Structures. In response to these needs, the concept of a multi-scale wireless sensor network is introduced in this study with a restricted input network activation scheme and the integration of data from a heterogeneous sensor array to improve damage detection for low-order models. The multi-scale network concept introduced here helps to improve power efficiency, minimize packet loss and latency, and eliminate synchronization issues through the use of a decentralized analysis scheme and the activation of sub-networks only in the vicinity of suspected damage, while reducing the required size of the reference pool for the undamaged state. This study introduces the network architecture concept, a strain-driven approach to damage detection and preliminary simulated results. PREVIOUS WORK IN WIRELESS STRUCTURAL HEALTH MONITORINGMost research in these areas of "intelligent" structural assessment and evaluation retain the traditional architecture of a centralized data acquisition hub wired to tens or even hundreds of sensors. As cost effectiveness is a major concern, the installation and maintenance of these cabled systems represent significant concerns, prompting the move toward wireless sensor networks, particularly those with local processing capabilities, thus reducing the amount of data transmitted in power-consuming wireless radio communications. Early work in this area was led by Straser and Kiremidjian [1] and advanced by Lynch et al.'s [2] dual processor format, followed by a later generation lowpower, multi-channel prototype [3]. Another example is the multi-hop WISDEN system [4], which uses the small MICA2 Motes, developed at the University of California at Berkeley [5]. In all of these applications, by reducing transmission from lengthy time histories to a number of key parameters, battery life of the wireless nodes can be extended, while the issues of strict time synchronization and loss intolerance in harsh environmental conditions are marginalized. Building on these prior efforts, the proposed approach offers a multi-scale network topology that is inherently more scaleable and exploits short wired communications for better energy-efficiency and reduced latency. SUMMARY OF KEY FEATURESThough such efforts have certainly made important contributions to the fiel...

Wireless sensor network to monitor an historic structure under rehabilitation

“…This design also reduces the possibility of interference between sensors by increasing time increments of data collection in areas that do not have perceived damage. In addition, Kijewski-Correa et al [8] recommend the idea of coupling strain gages and accelerometers for increased accuracy. The embedment of processors into wireless sensors is a possible option to save battery life.…”

“…This approach cycles through three different states to conserve energy: dormant state, sleeping state, and active state [7]. Another approach to save battery life is to utilize a multi-scale network, which only activates sub-networks in areas of suspected damage [8]. This design also reduces the possibility of interference between sensors by increasing time increments of data collection in areas that do not have perceived damage.…”

Reliable virtual sensing for wireless sensor networks

“…In [7], the authors used a similar idea to virtual sensing, called trigger sampling, for structure health monitoring and damage detection. Two sensors with different capabilities, m-nodes and μ-nodes, are deployed.…”

Ultrasonic wireless health monitoring system for near real-time damage identification of structural components

“…The availability of off-the-shelf affordable wireless components, and deployable small factor computational devices, along with the availability of a wide selection of sensors, enables the development of wireless-autonomous monitoring systems. Such systems can be deployed in almost any terrestrial situation and are limited in applications only by the types of sensor used for monitoring purposes [4][5][6][7][8] . On the other hand, the current defects detection methodology based on ultrasonic guided waves includes the deterrent effect of ambient noise and, more importantly, the need for rigorous manual analysis of the signals, which results in extremely time-consuming inspection procedures and strongly operator-dependent conclusions.…”