Structural optimization design of a bolster based on simulation driven design method

Simulation driven design method which use multiple optimization methods can effectively promote innovative structural design and reduce product development cycle. Meanwhile, the submodel technology which proceed more detailed simulation and optimization analysis can enormously improve the efficiency of modeling and solving. This study establishes a general workflow of structural optimization for stainless-steel metro bolster by combining the simulation driven design method and the submodel technology. In the submodel definition phase, the end underframe submodel which contains the bolster is obtained based on the whole car body FE model, and the effectiveness of the end underframe submodel is also proved. In the conceptual design phase, the topology path inside the bolster is obtained by topology method and the optimized structure of the inner ribs inside the bolster is determined according to manufacturing processes and design experiences. In the detailed design phase, the thicknesses of each part of the bolster are determined by size optimization. The simulation analyses indicate that the requirements of static strength and fatigue strength are fulfilled by the optimized bolster structure. Besides, the weight can be reduced by 11.18% and the weld length can be decreased by 17.79% compared with the original bolster structure, which means that not only the lightweight design goal is achieved, but also the welding quantity and manufacturing difficulty are greatly reduced. The results show the effectiveness of the simulation driven design method based on the submodel technology in the structural optimization for key parts of the rail transit vehicles.