Thermal-structure Coupled Analysis And Parameter Optimization Of Cutting Energy-absorbing Process

The development of urban rail transit set higher requirements for collision security. The special energy absorption device could absorb most of the impact energy at the moment of collision and protect the safety of passengers. Therefore, it has become a key subject in the field of collision safety.Traditional urban rail vehicles used more crushing energy absorption structure while cutting energy-absorbing process was deeply studied in the thesis, based on the theory that a lot of kinetic energy could be consumed in this process.As the influence of cutting heat has not been taken into consideration in the existing research results, Johnson-Cook material model was used to make a complete thermal-structure coupled analysis of this energy-absorbing process and truly simulate the entire process. The results showed that peak value didn’t appear in the impact force curve and the force value kept stable in the calculation which proved the energy-absorption by cutting was an ideal mode. In addition, the temperature changes were studied and lead to the conclusion that the thermal effect had an important influence on the energy-absorbing process. In this thesis, inertial effects of the thermal-structure coupling cutting energy-absorption and variable cross-section characteristics were also analyzed, the result of which told us that, unlike crushing energy absorption, this type of energy absorption did not have an obvious inertial effect, or the initial collision conditions had no effect on this process. However, the thermal effect was impacted significantly by the speed. What’s more, the section length and width of the work piece appears to be a nearly linear relationship with the impact force, but the two factors had no influence on the thermal characteristics."Cutting force per area" and "energy-absorption per volume" were proposed according to the fitting relation. Tool geometry parameters effect of the energy-absorption process was studied based on the prior research, after which the specific affecting mode was got by the orthogonal polynomial regression method. Then a group of cutting parameters was obtained using genetic optimization algorithms, in combination with collision performance requirements of the domestic subway vehicle. Furthermore, the detail design method was drawn on the basis of numerical simulation and a complete cutting energy-absorbing device was designed as well, laying a solid foundation of the specific application in future.The results achieved in this thesis had a great significance for the deeper study of the cutting energy-absorption process and its engineering applications.