A Finite Element Material Model and Method for Predicting the Cumulative Behavior of Energy Absorbing Components in Thermoplastic Bumper Systems Subjected to Multiple Impacts

The paper describes a finite element procedure and material model that can be used to predict the post-impact geometry of a thermoplastic bumper energy absorber. The material used in the study is a thermoplastic PC/PBT blend. The methodology presented determines the final geometric shape based on a new finite element material model. The material model uses a secant return modulus that is a function of the plastic strain. The conversion of material data into a finite element material model, along with a finite element procedure for analyzing multiple impacts, is discussed. Comparisons of finite element predictions to test data are also presented.