Finite Element Interface Technology for Modeling Delamination Growth in Composite Structures

Abstract

An effective and robust interface element technology is presented for connecting and simulating crack growth between independently modeled finite element subdomains, for example, composite plies. This method has been developed using penalty constraints and allows coupling of finite element models whose nodes do not necessarily coincide along their common interface. Additionally, the present formulation leads to a computational approach that is very efficient and completely compatible with existing commercial software. The present interface element has been implemented in the commercial finite element code ABAQUS as a user element subroutine, making it easy to test the approach for a wide range of problems. Additionally, the interface element formulation has been modified to simulate delamination growth in composite laminates. Thanks to its special features, the interface element approach makes it possible to release portions of the interface surface whose length is smaller than that of the finite elements. In addition, the penalty parameter can vary within the interface element, allowing the damage model to be applied to a desired fraction of the interface between the two meshes. Results for double cantilever beam and end-loaded split specimens are presented. These results are compared to measured data to assess the ability of the present damage model to simulate delamination growth.