Axial crashworthiness design of double-hat beams with various cross sections

In this work, five kinds of sinusoidal cross-sections, namely DCS1, DCS2, DCS3, DCS4 and DCS5, are proposed to improve the crashworthiness of double-hat beams (DHBs). The accuracy of simulation model is determined by experimental results. The influence of amplitude on their crashworthiness is discussed, and the mean crushing force (MCF) and specific mean crushing force (SMCF) values of DHB is significantly improved with these new cross-sections. DCS5, DCS2 and DCS3 models tend to have better collision performance compared with DCS4 and DCS1 models. On this basis, the influences of wavenumber and amplitude of DCS2 and DCS3 are further studied. Compared with DHB, the MCF and SMCF values of DCS2-4+10 and DCS3-4+10 increase by 102.07 % and 39.85 % as well as 105.99 % and 35.80 %, respectively. Furthermore, these sinusoidal DHBs show six typical deformation failure modes, namely axial collapse, irregular axial collapse, bending deformation, mixed deformation mode, lateral bending deformation and lower collapse. Two typical cross-sections are optimized with multi-objective algorithm to further improve the crashworthiness of DHBs. In summary, this work provides the design method of DHB, showing a variety of typical cross-sections, which is of great significance.