Real-Time Monitoring of Damage Development in Crossply Composite Laminates by Means of Ultrasonic and Acoustic Emission Methods

摘要

Studies on damage development in composite laminates have been conducted by many investigators [1–3]. In the case of crossply laminates under uniaxial tensile loading, whether monotonic or cyclic, the first stage of damage consists of transverse matrix cracking in the 90° plies. These cracks are nearly equidistant and increase in density up to a characteristic limiting value. In the later stages of loading, the damage evolves so that longitudinal cracks are generated in the 0° plies, followed by micro-delaminations at the intersections of the two sets of cracks, and finally fiber failures leading to global failure [1].