Thin-walled curved hexagonal beams in crashes - FEA and design

This paper focuses on the crashworthiness analysis and crash responses of thin-walled curved beams with hexagonal cross sections. An optimal design of hexagonal cross-sectional profile of such curved beams are obtained based on the observations of typical crash responses of a series of thin-walled curved hexagonal beam samples. The optimised curved beam achieves maximum energy-absorption capability. Detailed finite element (FE) models and finite element analysis (FEA) method are employed to investigate the crash behaviour of the curved hexagonal beams and provide the observations for the optimum design. In this design optimisation problem, the specific energy absorption is set as the objective, and the cross-sectional side length and wall thickness are selected as two design variables. The design samples are selected from design space using factorial design method, and the design problem is formulated based on the FEA results of the design samples, by the use of design of experiments method. Afterwards, simplified FE models are developed for the design samples of the curved hexagonal beams and are applied for the same design problem. It is verified that the developed simplified models lead to the same optimal design as the detailed models. A parametric study is also performed to reveal the influences of the selected design variables on the overall structures' crash responses.