Optimization of multiple collision characteristics using an innovative crashworthiness diagram

As the crashworthiness and weights of parts in vehicles are both directly influenced by the thickness of the corresponding materials, a reasonable compromise is required for the optimal design. In this study, an innovative crashworthiness diagram was proposed for optimizing the multiple collision characteristics of automobile components with respect to thickness. The crashworthiness diagram was designed to consider multiple collision characteristics, such as the impulse, energy absorption, and anti-intrusion displacement, based on a crashworthiness index (CI). The respective CI values were assessed both analytically and numerically to determine the optimal thickness of an alternative material. The use of aluminum alloys was investigated, aiming to improve the collision resistance while ensuring lightness. Based on the crashworthiness diagram, an Al7075-T6 bumper beam with a thickness of 2.5 mm was used to replace a 22MnB5 (HPF) bumper beam with a thickness of 1.4 mm. An experimental validation of the Al7075-T6 bumper beam through a drop-weight test confirmed that the proposed crashworthiness diagram is a feasible and reliable guide to determine alternative material with target collision resistance