Bending characteristics of top-hat structures through tailor rolled blank (TRB) process

Tailor rolled blank top-hat (TRBTH) structure, as a relatively new thin-walled configuration, was proposed in this study to better balance the crashworthiness and lightweight requirements, which was featured in a thicker wall thickness in the critical load-bearing areas and a thinner wall thickness in the other regions. To capture the non-uniform material properties and thickness variation of the TRBTH structure accurately, a more realistic finite element (FE) modeling technique was first developed and validated experimentally. It was found that the corresponding FE simulation results agreed well with the testing results. Second, the bending characteristics of TRBTH and uniform thickness top-hat (UTTH) structure with the equal mass were compared through the typical three-point and four-point bending conditions. It was revealed that the TRBTH had a higher bending resistance, which allowed absorbing more transverse crushing energy. Third, the detailed numerical analyses were performed for the bending deformation to explore the crushing advantages of the TRBTH structure more comprehensively. It was divulged that the TRBTH structures engaged more material to participate in deformation than the UTTH counterpart under the transverse loading. Finally, a parametric study was conducted to investigate the effects of the thickness distribution and length of thick zone on the three-point and four-point bending characteristics; and it was found that these structural parameters could affect the crashworthiness of TRBTH structure significantly in a form of different deformation patterns. For this reason, the bending characteristics can be further improved by optimizing the TRB parameters, making it more suitable for being an effective energy absorber.