PREDICTION AND OPTIMIZATION OF FATIGUE LIFE OF ELECTRIC DRIVE AXLE HOUSING FOR COMMERCIAL VEHICLE UNDER MULTIPLE CONDITIONS

In the course of real operation, the drive axle housing is likely to undergo fatigue failure due to prolonged exposure to cyclic alternating loads.To determine whether the drive axle housing of a commercial vehicle’s wheel-side electric motor complying with fatigue life requirements at the design stage, a three-dimensional model and finite element model of the drive axle were established. Firstly, an initial inertia release analysis was performed，indicating that its static strength and stiffness met the requirements.Secondly, based on this foundation，utilizing nCode DesignLife software, using the nominal stress method in conjunction with the material’s<italic> S</italic>⁃<italic>N </italic>curve and fatigue loading curve, a new automotive industry standard was employed to predict the fatigue life of the housing under multiple conditions，such as vertical bending fatigue, braking fatigue and lateral fatigue.The results revealed that the fatigue life of the drive axle housing under braking fatigue and lateral fatigue conditions did not meet the requirements set out in the standard, necessitating structural optimization. Finally, reinforcement optimization was performed on the drive axle housing. The results show that, through optimization，the maximum stress of the drive axle housing is reduced by 95.8 MPa and the maximum deformation is decreased by 1.064 mm under the maximum impact conditions.Additionally, the minimum fatigue life under three different fatigue conditions is improved respectively by 1.076 million cycles, 289 000 cycles, and 497 000 cycles, exceeding the requirements stated in the standards.This validates the feasibility of optimizing the drive axle housing structure, effectively shortening and reducing the research and development cycles and associated costs.