Real-time ultrasonic and acoustic emission monitoring of damage in graphite/epoxy laminates

Abstract

Progressive failure of a crossply composite laminate under uniaxial tension was characterized by correlating ultrasonic and acoustic emission measurements with damage in real time. Both ultrasonic backscattered energy and acoustic emission gave consistent results and proved to be sensitive indicators of matrix cracking and other failure mechanisms. The acoustic emission signals were analyzed by investigating the amplitude and count frequency and the corresponding applied strain. Loading/unloading tests showed that no additional damage occurs upon reloading up to the previous peak load.