Damping analysis in cyclic fatigue loading of sandwich beams with debonding

The aim of this study is to investigate the mechanical behaviour of sandwich composite materials with debonding under static and dynamic loadings. These sandwich composites consists of two thin faces composed of glass fibre and epoxy resin bonded to light weight and weaker core material of PVC foams. The tests were conducted in static and cyclic fatigue loading in 3-points bending with various debonding length. Static tests were performed to determine the failure parameters and the caracteristiques used in fatigue tests. The effects of debonding variable length on the stiffness, hysteresis loops and loss factor were studied for various numbers of cycles during cyclic fatigue tests. The results show that the stiffness, hysteresis loop and damping are sensible to debonding length. These properties offer the sensitive indicators of sandwich materials damage during lifetime.