Strength assessment and lightweight optimization design of a bogie frame based on the structural stress method

Purpose Achieve a lightweight design for a bogie frame while ensuring it meets strength requirements by conducting static and fatigue strength assessments and optimizing plate thickness. Design/methodology/approach Establish a finite element model and determine loads according to the UIC615-4 standard. Fatigue strength assessments are conducted using the structural stress method. Size optimization for plate thickness is performed with constraints on maximum static strength and total fatigue damage of the weld. Multi-objective optimization design is carried out using Isight software, with sensitivity analysis to identify key plates. The neural network model is chosen as the approximation model, and the NSGA-II multi-objective genetic algorithm is selected as the optimization algorithm. Findings The strength assessment reveals a significant margin. Through size optimization of plate thickness with constraints on static strength and fatigue damage, the frame’s mass is reduced by 9.59%, achieving a lightweight design while meeting strength requirements. Originality/value In many lightweight studies, the inclusion of fatigue assessment through the structural stress method in the optimization process is often overlooked. However, this paper addresses this gap by incorporating it and providing a detailed operational procedure. Such consideration holds reference value for the design of lightweight optimization, especially when fatigue strength is a critical consideration.