Finite Element Analysis And Optimization Design Of A Heavy-duty Vehicle Drive Axle Housing

Nowadays,due to the technological progress of the automobile industry and the rapid development of science and technology,the technological development of automobiles is getting faster and faster,and at the same time,people have more and more alternative modes of travel,and have higher and higher requirements for the modernization and intelligent degree of transportation.The function of the automobile drive system not only provides power for the automobile in the normal driving process,but also ensures the abundant power and the stability of the automobile body under certain working conditions(such as the big slope).In drive system,the drive axle housing as the main reducer,differential protection device of the parts and carrying vehicles and chassis quality also from between the wheels and the ground under the role of incentive and bending moment,therefore,in the design of the drive axle housing,reasonable design of drive axle housing structure and shape to improve the strength and stiffness of the bridge shell has the very vital significance.This thesis uses the finite element analysis methodis to carry out finite element statics analysis,modal analysis,random vibration analysis,transient dynamics analysis and fatigue life analysis on the drive axle housing of a heavy truck.Through the analysis results,the topology optimization design of the drive axle housing is carried out.The main research contents include:(1)The integral drive axle housing in the drive system is selected as the research object,and a three-dimensional model is established according to the structure of a heavy-duty vehicle drive axle housing.Five kinds of typical working condition of statics of drive axle shell finite element analysis,according to the running status of vehicles under different working conditions,impose constraints and load of drive axle housing and for its strength and stiffness in finite element analysis,analysis of the strength of the drive axle housing exceed the material yield strength and stiffness of the range is in line with the national standard.(2)Free modal analysis of the drive axle housing is carried out under unconstrained and unloaded conditions,and 6 order modes of the drive axle housing are analyzed under unconstrained and unloaded conditions;Then,the constrained modal analysis is carried out on the drive axle housing to analyze the natural frequencies and mode shapes of the 1st to 6th order modes of the axle housing when loads and constraints are applied;in order to verify the reliability and accuracy of the finite element simulation data,the drive axle shell is verified by free modal test,and by comparing the simulation data with the test data,it is analyzed whether the simulation and test data results are within a reasonable range.(3)On the basis of the constrained modal analysis,the random vibration analysis of the axle housing is carried out in combination with the analysis results.According to the 3?principle,the parameters are set in the finite element random vibration analysis,and the random vibration analysis of the drive axle housing under 1Sigma,2Sigma and 3Sigma is conducted in turn.Through the random vibration analysis under the modal analysis of the drive axle housing,the errors in the range of different extraction rates were analyzed,and the rationality of the structural design of the drive axle housing under random vibration was analyzed through calculation and simulation comparison.Based on statics analysis,respectively from the full bridge shell bending,the maximum vertical force when the bridge shell bending,maximum lateral force when the working condition of bridge shell bending three transient dynamic analysis was carried out on the drive axle housing,respectively,analysis of the three under the direction of normal stress,find out the most dangerous areas prone to when to optimize design of the bridge shell.The parts that should be strengthened should be designed in a targeted way.(4)Based on the static analysis results,the fatigue life analysis of the three most representative working conditions of the drive axle housing is carried out in the finite element fatigue analysis: axle housing bending under full load,axle housing bending under maximum vertical force,and axle housing bending under maximum lateral force.Combined with the fatigue life analysis theory and the analysis of fatigue life value and safety factor,it can be concluded that there is a certain optimization space for the drive axle housing.(5)Based on the above analysis,the lightweight optimization design of the drive axle housing is carried out by using the topology optimization design method in the finite element analysis.According to the results of topology optimization analysis,four polygonal holes and four U-shaped slots were opened on the body of the drive axle housing to maximize the space utilization under the premise of ensuring the stability of the structure,and finally realize the purpose of lightweight.Finally,the static,modal and fatigue analysis of the drive axle housing before and after optimization shows that the optimization scheme is reasonable.