Session: 12-02: Structural Health Monitoring II

Paper Number: 135251

135251 - Frequency Wavenumber Design of Piezoelectric Sensors for Impact Monitoring 

Abstract: 

Structural health monitoring (SHM) techniques are essential for ensuring safety and preventing failures in critical infrastructures. Ultrasonic guided waves allow large areas of structures to be monitored due to their long-distance traveling capability. Impact monitoring exists as an important topic in SHM to trigger alarms of timely inspections, which allows early evaluation and maintenance of impact locations. The conventional impact monitoring approaches generally require temporal signal information from multiple sensors functioning as an array, giving rise to concerns of hardware cost, system complexity, and spatial coverage limitation. As a result, a novel sensory system is desired for detecting the occurrence and orientation of the impact.

This paper proposes a novel piezoelectric sensor for impact orientation detection via the frequency wavenumber design. The spatial distribution of the electrodes allows distinguishing the in-coming wave direction by coupling with corresponding wavelength. The sensor system consists of a spiral pattern piezo ring and a piezo disc at the center. The incident wave orientation from the impact can be evaluated by comparing the frequency components picked up by the aforementioned piezo elements. This research initiates with the analysis of the frequency spectra mathematically to determine annular electrode patterns, including inner radius, element width, width-spacing ratio, and number of elements, as well as to determine how these various parameters uniquely affect the sensing properties of the transducer. Subsequently, a two-dimensional impact numerical model is meticulously constructed to demonstrate the good agreement of analytical and numerical results. Then, the three-dimensional transducer numerical simulations are conducted for investigating and validating the impact monitoring reliability. The corresponding frequency-band of different angular directions is unique in the transducer, coupled with the guided wavelengths generated by the impact pulse. The results show that the proposed method can accurately locate the impact with only two sensors, simultaneously providing a high degree of reliability. Finally, the experimental demonstration is performed, yielding excellent agreement with the developed theory and showing good agreement in most cases. The paper finishes with summary, concluding remarks, and suggestions for future work.

Presenting Author: Shulong Zhou Shanghai Jiao Tong University

Presenting Author Biography: He is a Ph.D. candidate student from University of Michigan-Shanghai Jiao Tong University Joint Institute

Authors:

Shulong Zhou Shanghai Jiao Tong University
Yanfeng Shen Shanghai Jiao Tong University