Finite element analysis of CFRP laminates subjected to compression after edge impact

Abstract

Composite structures are particularly vulnerable to impact which lowers drastically theirs residual strength. In particular, the edge impact on composite stiffener is known as a critical factor on the loss of residual compression strength. Then it is necessary to develop a model able to simulate impact and compression after impact in order to numerically optimize composite structures within impact damage tolerance.In the present paper, a unique model, based on Discrete Ply Model, allows to simulate edge impact and compression after impact (CAEI) of two stacking sequences highly oriented, representative of a real aeronautical stiffener structure. A relatively good correlation is found between experiment and model regarding the important number of phenomena which is taken into account: permanent indentation after impact, force–displacement impact curve, crack length after impact, delamination after impact, stress-displacement CAEI curve, stress-out-of-plane displacement curve, CAEI final failure. Moreover only 14 parameters are needed to feed this model, and all are obtained using standard tests and have physical relevance. This concept is important because it allows considering running similar tests with other materials without performing complex and special identification tests but only using physical parameters of standard tests. The good results of this approach could allow to define a new design method to improve the edge impact damage tolerance.