Axial crashworthiness of double-hat beams with various ribs

Double-hat beam is a thin-walled structure with excellent crashworthiness. The current research on improving the crashworthiness of double-hat beam through the design and arrangement of ribs is not sufficient. In this work, the axial crashworthiness of double-hat beam with various ribs is systematically investigated. Four kinds of ribs and seven types of mixed ribs are proposed. The results show that vertical ribs help to enhance the impact performance of double-hat beam, the specific mean crushing force (SMCF) values of VR-3 and VR-5 are, respectively, 8.3% and 8.4% higher than that of double-hat beam. Transverse and diagonal ribs are beneficial to obtain stable crushing forces and deformation patterns. The SMCF value of MR-1 is 7.25% higher than that of TNRN-1 and 13.33% lower than that of VR-5. The performance of a mixed double-hat beam is always between the two original double-hat beams that make up it. The double-hat beams exhibit the deformation patterns of axial crushing, bending and torsion. In addition, the multi-objective optimizations of three typical double-hat beams are carried out. The thickness of double-hat beam's components is defined as variable, and the optimisation objectives are maximise mean crushing force and minimise structural mass. The SMCF value of the third solution of VRN-3 selected in this study increases by 24.42% compared with double-hat beam. In summary, the collision performance and deformation pattern of the double-hat beam can be controlled by the design of ribs.