Influence of forming parameters on the crash performance of capped cylindrical tubes using LS-DYNA follow-on simulations

摘要

In the automobile industry, accurate prediction of crashworthiness indicators is important in designing energy absorbing tubes for the protection of occupants. However, the deformation behavior of these tubes was found to be affected by the prior manufacturing (forming) process. Hence, it is necessary to incorporate these forming effects in the crash simulation model to improve the accuracy of the simulation results. Therefore the interactive computational approach was used in this research article to account for the forming and crash response of the proposed capped cylindrical tubes. In this procedure, the design of forming tools based on the computer-aided automated computing system is performed first and the results are considered in the multi-stage deep drawing process. Then, the influences of forming parameters of a multi-stage deep drawing process on the axial crushing response of thin-walled capped cylindrical tubes were numerically examined using LS-DYNA follow-on simulations. The residual forming history such as effective plastic strain, thickness variation, and residual stress was mapped to crash simulation models in order to understand the interaction between the forming process and subsequent crash performance of the proposed tubular structures. The capped cylindrical tubes of shell element with a constant thickness of 1.63 mm were also simulated for comparison purpose. The finite element crash model included with forming simulation results caused an increase in the initial peak crushing force by 15-30% over constant thickness tubes. In order to validate the numerical simulation results, experiments were performed. The application of a constitutive crash simulation model considering these forming parameters when studying the axial crushing characteristics of the tubular structures that have experienced earlier forming processes is strongly recommended.