Experimental and numerical analysis of residual compression strength after Low-Velocity Impact of carbon/epoxy composite plate

Abstract

A composite laminate is susceptible to Low-Velocity Impact (LVI) load, leading to Barely Visible Impact Damage (BVID) accompanied by invisible damage in the form of delamination. Such delamination is significantly reduced the compression strength of the composite laminate plate. The present work provides an experimental and numerical analysis, based on finite elements, on residual compression strength after the low-velocity impact of carbon/epoxy composite plate. Five specimens of 16 layers Unidirectional carbon/epoxy composite plate with fiber orientation [+450/900/-450/00/+450/900/-450/00]s have been tested subject to low-velocity impact load, with a single use of impact energy value of 2.75 Joule/mm, followed by compression test. Moreover, another similar five specimens tested compression before impact to measure its compression strength. Experimental results were observed to identify the profile and size of total-projection delamination after impact and after compression and compression-strength before and after impact. The Finite Element analysis is based on the utilization of cohesive zone elements with Benzeggagh-Kenane fracture criterion to predict the initiation and propagation of delamination, Kirchhoff based formulation of continuing shell element to model stiffness of the laminate, and Hashim-Rotem damage mechanism to predict intralaminar damages.