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