Simulation Research On Aluminum Alloy Car Body Structure Of Straddle-Type Monorail Vehicle

With the rapid development of China’s urban rail transit,the construction and promotion of straddle-type monorail transit have alleviated the current situation of urban traffic congestion.Not only met people’s travel needs but enriched the development forms of rail transit.In order to test the rationality of car body structure design and ensure the safety in operation,it is necessary to carry out finite element structural simulation analysis of car body in the design stage.With the wide application of straddle-type monorail,higher requirements are put forward.On the basis of ensuring safety,structural optimization design is carried out.The method improves design efficiency and economic utilization rate.This paper describes the development history,present situation and future prospect of straddle-type monorail at home and abroad.Take a straddle-type monorail aluminum alloy car body as the research object.On the basis of fully understanding and mastering the structural characteristics,operating environment,relevant technical standards and mechanical properties of aluminum alloy materials,a simplified geometric model is established by using finite element analysis software.And a reasonable finite element model of the car body is established by selecting suitable elements according to the geometric model.According to the relevant specifications,11 calculation conditions are established.The finite element simulation analysis of the car body is carried out.The strength,stiffness and modal frequency of the car body are checked,which all meet the standards.Moreover,the strength of the car body structure is abundant.It provides a basis for further optimization of the car body structure.Based on the theory of sensitivity analysis and relative sensitivity analysis,the mass sensitivity,displacement and modal frequency sensitivity and relative sensitivity of the car body are comprehensively analyzed.From 92 design variables of the whole vehicle,23 design variables are selected.They are beneficial to the weight reduction of the car body without excessively reducing its performance,or improving its performance without excessively increasing its weight,or both.The size optimization based on discrete variables is carried out.The car body mass is reduced by 344 kg.Taking the impact seat of the optimized car body underframe as the research object.The topology optimization is carried out.And the utilization ratio of materials is improved.Compared with the original structure,the weight of the optimized impact seat is reduced by 46.6kg and 22.2%.After twice optimization,the total mass of the car body is reduced by 390.6kg and 7.5%compared with the original scheme,which is feasible.The research method adopted in this paper provides a theoretical basis for the design of straddle-type monorail car body structure in the future.