Method to Predict the Energy Absorption Rate Characteristics for a Structural Member

The rate of energy absorption during the plastic deformation of structural components is an important factor in the design of automotive safety systems such as chassis crumple zones. This paper describes a design tool for predicting energy absorption characteristics. The tool was based on measurements of the energy absorption rates of twenty-three selected materials subjected to three impact energy conditions. A well-established finite element code, LS-DYNA3D, was used with a mesh representing a hollow column of square cross-section to establish a database of energy absorption characteristics. A mathematical model representing the energy absorption rates was determined and the material properties most influencing the energy absorption rates were identified. A parabolic model best represented the energy absorption charactersitics. The regression coefficients for the model were determined for all tested materials under the selected test conditions. In this study, the most influential material properties affecting the energy absorption rate were yield strength and tangent modulus of elasticity. Cluster analysis and principal component analyses were performed in creating a design tool. The results include identification of clusters of materials which show significantly similar behavior and a mathematical model representing the typical rate of energy absorption for materials in those clusters.