Lightweight Multi-objective Optimization Design For Cast Steel Axle Housing Of Heavy Dump Truck

Driving axle housing is the main load bearing,force transferring component and installation substrate of driving axle system,driving axle housing lightweight design largely increase the design space of driving axle system,at the same time,improve the carrying efficiency and ride comfort of vehicle.Driving axle housing lightweight design is the premise and foundation and it decides the lightweight space and level of whole axle system.In this paper,multi-objective lightweight optimization method is utilized to coordinate the coupling relationships existing between the mass,fatigue life,strength,stiffness and modal frequency of driving axle housing.Based on the national automobile standards QC/T533-1999 "Automobile driving axle housing bench test method",making analysis of driving axle housing on vertical bending stiffness test,vertical bending fatigue bench test,strain test of the key loading points in axle housing body,and the rigid displacement,fatigue life,static and dynamic load stress time history of key points under bench test condition is obtained.Virtual bech test results simulated by virtual driving axle housing bench test finite element model are compared with actual bench test,verifying high precision of virtual bench test model.Conducting the simulations of axle housing in maximum vertical force,maximum pulling force,maximum braking force,maximum lateral force and maximum static stress conditions,the results show that axle housing has more space on the performance on stiffness and strength.7th to 16th order modal vibration mode and frequency values are obtained through free modal analysis,and the modal evalution index is finally putting forward.The accuracy of vertical bending fatigue life prediction is verified by contrast between the fatigue life and dynamic stress of key points of vertical bending fatigue life analysis under 3.0 times full loading condition and the actual fatigue test result.The vertical load spectrum on axle housing leaf spring seat is obtained through applying combination and strengthening road spectrum into the 8×4 virtual prototype model of dump truck established on multi-body dynamics theory,and the fatigue life analysis of axle housing under load spectrum impact is carried out.Axle housing body weight loss 10.25 kg and its optimized structure is more uniform through multi-condition topology optimization and shape optimization method.46 axle housing sample models under different wall thickness parameters are built using CATIA parameterized modeling,ANSA grid batch meshing and optimal latin square sampling technology by selecting axle housing wall thickness as design variables,and static strength,bending stiffness,first-order modal frequency and fatigue life value under load spectrum impact of axle housing sample models are obtained by simulation,defining mass and fatigue life of driving axle housing as optimization goal,combinaed with RBF approximation model and multi-objective genetic algorithm,finally the best combination of wall thickness is obtained through optimization.Based on fatigue life,Multi-objective lightweight design of axle housing axle tube and package is carried out,axle housing weight loss 8.4kg and its various performance indicators meet design requirements.After the contrast of various performance indicators of axle housing structure before and after the lightweight optimization,driving axle housing lightweight evaluation method is proposed.