Design and Analysis of Composite Front Bumper Crush-can System

Composite materials provide an avenue to achieve weight savings in structural automotive components due to their low density, high structural performance, and excellent energy absorption during impact. However, many challenges exist in implementing composites in automotive applications, including manufacturing throughput, part quality, part cost and the relative immaturity of prediction capabilities during the design phase. The latter, in particular, can limit weight savings and increase cost by requiring overdesigned components and a reliance on extensive physical validation testing.

The Validation of Material Models for Crash of Carbon Fiber Composites project is a four-year Cooperative Agreement project between the U.S. Automotive Materials Partnership (USAMP) and the US Department of Energy (DOE). The primary objective is to validate and assess the ability of physics-based material models to predict crash performance of automotive primary load-carrying carbon fiber composite structures. Models evaluated include Automotive Composites Consortium/USAMP-developed models from the University of Michigan (UM) and Northwestern University (NWU), as well as four major commercial codes: LS-DYNA, RADIOSS, VPS (PAM-CRASH), and Abaqus. Predictions are compared with experimental results from quasi-static testing and dynamic crash testing of a lightweight carbon fiber composite front-bumper and crush-can (FBCC) system which was selected for demonstration via design, analysis, fabrication, and crash testing. Performance targets and the physical design space for the composite FBCC system were derived from physical testing and virtual simulation of a surrogate steel FBCC. This paper will discuss the results from experimental testing and CAE predictions as well as the sources of gaps between them. Special focus will be placed on how these results can be used for design considerations of carbon fiber composite energy absorption systems.