Active damage localization for plate-like structures using wireless sensors and a distributedalgorithm

Abstract

Wireless structural health monitoring (SHM) systems have emerged as a promisingtechnology for robust and cost-effective structural monitoring. However, the applications ofwireless sensors on active diagnosis for structural health monitoring (SHM) have not beenextensively investigated. Due to limited energy sources, battery-powered wireless sensorscan only perform limited functions and are expected to operate at a low duty cycle.Conventional designs are not suitable for sensing high frequency signals, e.g. in theultrasonic frequency range. More importantly, algorithms to detect structural damage witha vast amount of data usually require considerable processing and communication time andresult in unaffordable power consumption for wireless sensors. In this study, anenergy-efficient wireless sensor for supporting high frequency signals and a distributeddamage localization algorithm for plate-like structures are proposed, discussed andvalidated to supplement recent advances made for active sensing-based SHM. First, thepower consumption of a wireless sensor is discussed and identified. Then the design ofa wireless sensor for active diagnosis using piezoelectric sensors is introduced.The newly developed wireless sensor utilizes an optimized combination of fieldprogrammable gate array (FPGA) and conventional microcontroller to addressthe tradeoff between power consumption and speed requirement. The proposeddamage localization algorithm, based on an energy decay model, enables wirelesssensors to be practically used in active diagnosis. The power consumption for datacommunication can be minimized while the power budget for data processing can stillbe affordable for a battery-powered wireless sensor. The Levenberg–Marquardtmethod is employed in a mains-powered sensor node or PC to locate damage.Experimental results and discussion on the improvement of power efficiency are given.