Mechanical behavior and acoustic emission technique for detecting damage in sandwich structures

The present study investigates the mechanical behavior under static and dynamic loadings and assesses damage by the acoustic emission method of two types of sandwich composite materials. The sandwich structures under study are both made of cross-ply laminates as skins and PVC closed-cell as foam with different densities: 60 kg m−3 and 100 kg m−3. The mechanical behavior tests were conducted in static and cyclic fatigue loadings under 4-point bending. The sandwich structures considered in fatigue tests were damaged by a various number of shear damages in the foam. Static tests were performed to determine the failure parameters and characteristics used in fatigue tests. The damage density effect on the stiffness, hysteresis loops, dissipated energy and damping of sandwich structures, were studied for various numbers of cycles during cyclic fatigue tests. The acoustic emission method was used to identify and characterize the local damage in both types of sandwich materials under static 4-point bending tests.