Detection and Localization of Micro-Cracks in Plate Structures Using Topological Acoustic Sensing

Abstract

This work presents an emerging technique called topological acoustic (TA) sensing for identifying micro-cracks in plate structures. The geometric phase change – index (GPC-I) from TA sensing is defined as the damage index (DI) to indicate the presence of micro-cracks. Then a localization methodology adopting GPC-I is proposed to identify random locations of micro-cracks occurrence in plate structures. Finite element method (FEM) based analysis is carried out in Abaqus/CAE software for 1) modeling contact acoustic nonlinearity (CAN) arising from micro-cracks and 2) verifying the proposed localization method. Numerical results show that micro-cracks induced CAN can be properly generated in FEM with artificially changing the cracks’ surface properties. Random locations of micro-cracks occurrence in plate structures can be identified accurately with the proposed localization method. Compared to the amplitude ratio (AR) parameter, the newly developed GPC-I can give more robust and distinguishing features for localizing micro-cracks. The velocity ratio (VR) parameter fails to capture nonlinear response arising from micro-cracks. This work is the first attempt to investigate the capability of GPC-I in capturing nonlinear response generated from micro-cracks. Such capability of GPC-I for topological acoustic sensing can provide new insight to benefit nonlinear ultrasonic community.