Active Self-Sensing Scheme Development for Structural Health Monitoring

Abstract

Smart materials such as Lead Zirconate Titanate (PZT) have been widely used for generating and measuring guided waves in solid media for structural health monitoring (SHM) applications. In this study, a self-sensing system, composed of self-sensing algorithms and a self-sensing circuit, is developed so that a single PZT wafer can be used for simultaneous actuation and sensing. First, a PZT wafer is modeled as a single capacitor and a voltage source, and the proposed self-sensing scheme is calibrated by applying a probing waveform. Then, the mechanical response of the PZT wafer coupled with the target structure is extracted from the measured PZT output voltage when an arbitrary excitation is applied to the same PZT wafer. While existing self-sensing techniques focus on vibration controls, the proposed self-sensing scheme attempts to improve the accuracy of extracted sensing signals in the time domain. The simplicity, adaptability and autonomous nature of the proposed self-sensing scheme make it attractive for continuous monitoring of structures in field. The effectiveness of the proposed self-sensing scheme is investigated through experiments of a cantilever beam.