Crashworthiness of composite and aluminum thin-walled boxes-A numerical study

Crash box is one of the most important parts in aeronautic and automotive vehicles as a crash energy absorber. Specific Energy Absorption (SEA) and peak load are key parameters in crashworthiness design of a crash box so that it should be had minimum peak load, the maximum energy absorption, and the minimum weight to save passengers. Metallic energy absorber such as aluminum or steel usually absorb the energy by folding or hinging, involving extensive plastic deformation during crushing. While composite materials have little or no plastic deformation because of their progressive failure mechanism. This is an important parameter in crashworthiness that allows a larger amount of energy to be absorbed. In this study, the axial collapse behavior and energy absorption capacity of aluminum and carbon/epoxy composite crash boxes were studied using the Abaqus/Explicit finite element solver. Both crash boxes were simulated with similar boundary conditions and loading. Finite element results are validated by the experimental results available in the literature. Comparison of the load-displacement curves of the aluminum and composite crash box illustrates that composite crash box has higher SEA and lower initial peak force which makes it superior compared to aluminum crash box in axial crushing.