STTR Phase I: Piezoelectric Fatigue Fuse Based Wireless Sensor Network

The broader impact/commercial potential of this project is to establish a precedence for remote, real time assessment of the safety and serviceability of infrastructural assets through the development of a self-powered structural health monitoring system. This piezoelectric fatigue fuse (PFF) will enable the establishment of quantifiable metrics to discern the current state of life as well as projected lifetimes and reparability criteria for assets ranging from bridges, to oil platforms, to ship hulls, and optimistically to any steel structures where fatigue is the primary mode of failure. With the remotely accessible, real time metrics provided by the PFF, asset owners will be able to make informed decisions regarding visual and other nondestructive inspection frequency and thereby reduce overall cost of maintenance, inspection and operation. Over the course of the design and evaluation of the sensors, an assessment of the underlying effects of fatigue crack nucleation and propagation through designed stress concentrations in coupled electromechanical systems will be performed. This work will illuminate the material and geometric constraints necessary to optimize piezoelectric transducers to provide adequate power and robust signal to noise ratios for fatigue sensing under real world, dynamic spectrum loading scenarios. This Small Business Innovation Research (SBIR) Phase I project to design and develop a piezoelectric fatigue fuse aims to address the growing problem of transit asset management in the United States. The recent series of bridge failures in the US exemplifies the public safety risks of ageing infrastructure and without a method to inspect and monitor fatigue in steel structures with improved accuracy and efficiency, the safety and serviceability of these structures is at an ever-increasing risk. The aim of developing and introducing PFF?s is to provide a measure of loading history that correlates with fatigue crack growth to predict current state-of-life and dictate economic options for future inspection and repair frequency. This will be accomplished by developing a system which transduces the mechanical loading of a structure into electrical energy which is simultaneously used to charge low-power electronics and generate digital data corresponding to the fatigue life of the asset. The key technical results of this program will be the measured electrical response of optimized PFF sensors, an understanding of signal modulation as the mechanical fuses accrue fatigue damage and the requirements of the low power electronics and radios necessary to make these systems truly self-powered.