Abstract

A premature fatigue failure that occurred prior to the expected load cycles during the vertical fatigue tests of a truck rear axle housing prototype was studied. A seven degree of freedom dynamic model of truck was presented and vibrating equations on automobile as a whole was also built based on the model. Random road roughness data in time history that is generated by random phase method were applied to vibration differential equations to acquire dynamic load imposed on the rear axle housing. Fatigue failure of the rear axle housing finite element model was predicted after the dynamic load was imposed on it. The simulation results showed that there were premature fatigue failure regions at Banjo transition of the rear axle housing. Results provided from tests were compared with the analyses. The simulation results were same as the fatigue tests. Design enhancement solutions were proposed to increase the fatigue life of the housing according to the simulation and test results.

Key words: Fatigue failure, finite element analysis, automobile dynamics, solid axle, rear axle housing.