Multi-scale analysis and hierarchical optimization design of a 2D twill woven composite front firewall for electric vehicles

Abstract

In high-performance electric sports vehicles, the application of woven composite materials with the purpose of lightweight has become an inevitable choice. It is considerably difference between traditional metal materials and composites for the lightweight design strategy of electric vehicle structures, due to the multi-scale and anisotropic characteristics of fiber reinforced composites. Nevertheless, most of scholars are focus on the meso-scale mechanical responses of woven composites, and few studies are involved in their multi-scale mechanical behaviors and hierarchical design strategy of composite structures in electric vehicles. In this work, a multi-scale analysis strategy was proposed to investigate mechanical behaviors of composite front firewall. Subsequently, a hierarchical optimization strategy with the objective of lightweight design of composite front firewall was carried out. Finally, a reasonable layout scheme of composite front firewall was quantitatively obtained. The maximum errors between the predicted and theoretical/experimental results in terms of equivalent engineering constants of fiber yarns and 2D twill woven composites (2DTWCs) were 8.8 ​GPa and 7%, respectively. It indicates that the multi-scale models can be used to evaluate the mechanical properties of 2DTWCs. Additionally, the total weight of optimized composite front firewall was reduced by 36% in comparison with the reference, and simultaneously the total stiffness was improved by 26%. Hence, it is an effective strategy to design lightweight composite structures of electric vehicles. We hope the proposed multi-scale and hierarchical design strategy could promote the further development of composite structures in high-performance electric sports vehicles.