Design And Optimization Of The Bogieframe For Suspended Monorail Vehicle

The suspended monorail transportation system has broad application prospects in China,and bogie is the key to realize the excellent characteristics of its vehicle.Frame is the main bearing structure of bigie,the mechanical properties of the frame directly affect the safety of train operation.This paper proposes a design scheme for the suspended monorail vehicle bogie.Based on the actual force condition of bogie and EN13749 standard,a method for evaluating the strength of bogie frame is deduced.Then the structure is optimized according to the strength analysis results.Finally,the comprehensive performance of the optimized structure is investigated,and the rationality of the optimized structure is verified.The main research contents and conclusions of this paper are as follows:1.Referring to foreign mature technology,the design scheme of the new type of suspended monorail vehicle bogie is proposed,which has the characteristics of compact structure,small cross-sectional area,strong climbing and curve passing performance.The structure and function of the important components such as the bogie frame are analyzed,and the transmission paths of the three directional force on bogie are obtained.2.Based on the special structure of the bogie of the suspended monorail vehicle,and considering the contact of anti-swing caused by the swing of the car body when the vehicle crosses the curve and the turnout,the calculation results of the load and the load case are determined by deduced from standard EN13749.Furthermore,the finite element method is used to evaluate the static strength of the frame.The calculation results show that the static strength of the frame meets the requirements,but there are some shortcomings such as unreasonable material distribution and unequal stress.3.According to the strength analysis results,the structure of the frame is optimized by combining the finite element method with the optimization design theory.The DWIG method is used to executed topology optimization of the motor mounting seat and the guide wheel mounting seat at the end of the frame,which improves the working environment of the brake disc and reduces the quality of the optimized area by 7.7%.By comparing the optimization results of the reduced model and the complete model,it is proved that the DWIG method can improve the optimization efficiency while guaranteeing the accuracy.The topology optimization method is used to optimize the arrangement of the internal stiffeners in the frame,which alleviates the stress concentration at the inner ribs,and theoverall force of the frame is more uniform.On the basis of completing the topology optimization,size optimization is carried out in the frame under various load case by taking the thickness of steel plate as the design attribute.The overall quality of the frame is reduced by 14.8%,and the weight loss effect is obvious.4.By comparing the static strength analysis results of the frame before and after optimization,it is found that the optimized frame stress distribution is ameliorated and the material utilization rate is greatly improved.Based on the fatigue limit method,the fatigue strength of the optimized frame is evaluated.The results show that the fatigue strength of the frame meets the requirements.Free and constrained modal analysis of the frame is carried out.The results show that the optimized frame has good dynamic characteristics and will not resonate with the car body and rail beams.The stiffness of each part meets the application requirements.