A Mesh Insensitive Composite Damage Model for Crash Simulations

Abstract

The usage of advanced lightweight materials such as polymer based composites is one direction to meet today’s requirements and regulations regarding energy efficiency. This is especially true for the automotive industry, where the usage of lightweight components can substantially lower the fuel consumption. However, sometimes these components carry critical structural loads and represent key safety parts. Therefore being able to predict by simulation the crash and strength performance of such materials is crucial starting in the early stages of the design process. State of the art mechanical simulation software not only provide elastic stiffness properties, they aim at predicting the progressive damage and failure limits of the composite part. However, the available damage and failure models may only be able to predict the point of damage initiation or suffer from numerical drawbacks such as a strong mesh dependence. Therefore, numerous research teams focus on the development of both robust and accurate progressive damage models for composites. A promising approach has been published recently by Pineda and Waas [1]. It is based on the definition of characteristic failure planes and the internal transition from a continuum to a cohesive based formulation. The damage model has been successfully implemented in the FE software package ESI Virtual Performance Solution (VPS). This allows for an explicit simulation of complex composite structures under dynamic loading such as they occur in a crash simulation. The implementation is subsequently evaluated for a variety of test cases and compared with standard continuum based formulations. The investigated models range from simple coupon tests to complex crash models.