Delamination Depth in Composites Laminates With Interface Elements and Ultrasound Analysis

Abstract

Abstract: This paper deals with the impact‐induced damage depth for laminated composite plates under low velocity impact. The numerical model developed here is an interface element compatible with the eight‐node isoparametric hexahedral element, present in Modulef software. This new element allows modelling the behaviour of the damage interface, considering a three‐dimensional stress state, the interpenetration constraint and the propagation of the delamination. The use of the interface element and of the damage model is proposed to predict damage for low impact velocities and to obtain accurately the shape, size and defect depth of delaminations in carbon‐epoxy [0,90,0,90]2s and [0,90]8 laminates. The laminate is also simulated using a damage model based on the indirect use of fracture mechanics implemented in Abaqus software. The defects in the impacted specimens were then inspected by ultrasonic C‐scan technique and by electronic speckle pattern interferometry as a comparative method. A good agreement between numerical results and experimental testing is demonstrated.