Numerical simulation of bearing capacity of carbody for high-speed train subjected to longitudinal impact

The static tension and dynamic compression experiments of the aluminum alloy 6005A-T6 and 6082A-T6 used in the carbody of high-speed train were carried out, their strain rate effects within the strain rate range of 0.001-2 500 s^-1 were identified, and the corresponding Johnson-Cook constitutive model was established. An explicit dynamic analysis model for the typical vehicle of high-speed train was constructed, the process of the carbody impacted by a rigid wall was simulated, and the influence of coupler stable force, impact speed, and loading condition on the bearing capacity of the carbody was investigated. The deformation evolution of the carbodies 1 and 2 for the high-speed train subjected to the impact load was analyzed, the bearing capacity of the carbody was determined by finding the critical point of stress change, and the crashworthiness of the train configured with a higher energy mode was analyzed for the performance verification. Research results indicate that the strain rate sensitivity coefficients of the 6005A-T6 and 6082A-T6 aluminum alloys are 2.9×10^-3and 8.5×10^-3 within the strain rate range of 0.001-2 500 s^-1, respectively, so their strain rate effects are not obvious. Under the axial dynamic impact load, the strengthening effect of the strain rate has no obvious effect on the bearing capacity of the aluminum alloy carbody structure, and the inertial effect is the main reason that its bearing capacity is higher than the static limit. When the longitudinal impact load is transmitted at the coupler position, the dynamic bearing capacity limitations of the carbodies 1 and 2 are obviously higher than the maximum allowable value under the static compression. The bearing capacity of the carbody structure under the impact load can provide an upper bound for the platform force of the energy absorbing element used in the interfacial energy distribution problem of the high-speed train collision. It is recommended to enlarge the mechanical parameters' design domains of the energy absorbing components by appropriately increasing the allowable load, meeting the passive safety performance of the train considering more severe requirements. 1 tab, 22 figs, 31 refs.