Low-Frequency Vibrothermography Using Lightweight Piezoelectric Actuators: The Location of Excitation and Application to Composite Materials

This article presents a novel infrared thermographic approach for damage detection by utilizing the heat generated around damage sites during vibrations below 1000 Hz induced by lightweight piezoelectric actuators. In this research, the optimal location of excitation was first investigated through finite element analyses, where two generalized equations were obtained to describe the relationship between the excitation and the resulting displacement response. These observations were then verified experimentally on an aerospace-grade composite plate, followed by vibrothermographic tests conducted on the same structure to demonstrate the effectiveness of the proposed damage detection process employing only a single lightweight piezoelectric disk as the actuator.