A Hybrid Model Based on Pitch-Catch and Pulse-Echo Configurations for Optimization of Placement of Piezoelectric Wafers

Abstract

The development of Structural Health Monitoring (SHM) systems, and integration in our structures, became a necessity as it has proven to provide a robust and low-cost solution for monitoring the structural integrity, and has a better ability to predict the remaining life of structures. One of the most important aspects of SHM systems is the design and implementation of sensor networks.

This study proposes a new hybrid approach for optimizing piezoelectric (PZT) wafers on convex and non-convex structures. The developed model aims at minimizing the number of wafer elements used while ensuring a high level of coverage within the monitored area that is discretized into a set of control points. The model combines two modes of communications (pitch-catch and pulse-echo) between actuator-sensor pairs, ultimately to achieve the desired coverage with a reduced number of PZT elements.

The efficiency of the proposed model is demonstrated by simulating different geometrical shapes. Significant improvement in the coverage, reaching 34.6%, of the monitored area, was achieved when compared to the coverage provided by the preliminary solutions. The combination of the two configurations of pitch-catch and pulse-echo in the same model highly impacted the coverage in the blind zones (corners and edges) where a single configuration may not be effective.

Experimental validation was carried out to evaluate the model accuracy in damage localization within the optimized sensor networks. The results demonstrated the proficiency of the model developed in distributing the PZT wafers on the tested specimens.