Durability Fatigue Behavior and Vibration Modal Parameter Frequency Sweep for China-Made Car Rear Axle

Abstract

In order to research the fatigue fracture problem of the rear axle of a China-made car at the reliability test stage on the durable enhancement roads of proving ground, and the strain loading spectrum of the rear axle fracture location and the weak points of the finite element analysis was measured. The fatigue damage of the broken crack at the rear axle on the durable enhancement roads was calculated and contrasted detailedly. At the same time，a six-channel MTS coupling system is used to conduct the vibration mode frequency sweep to the rear axle and car body of test car and the benchmarking car，and through vibration frequency sweep，an analysis of the reason of differences between the two cars and its relationship with the car body vibration frequency is made. The enhancement test and frequency sweep results show that the fatigue damage of two vehicles focuses mainly on the washboard road，the impact of the speed on the fatigue damage of the test car fluctuates significantly, the damages of the two cars vary greatly when the forced vibration excitation frequency of the washboard road is greater than 20Hz and the vibration modal frequency of the rear axle is close to the excitation frequency of the washboard road, causing high stress distribution and then fatigue fracture to the rear axle of the test car. The test results have provided an important basis for the structural improvement of the broken rear axle and the enhancement in the fatigue strength of the rear axle.