In order to predict the fatigue life of thrust rod heavy duty commercial vehicle balanced suspension, based on the continuum mechanics theory, the fatigue life prediction model of rubber with equivalent effect as damage parameter is established. Based on the equivalent stress and fatigue cumulative damage theory, the fatigue damage evolution equation of rubber material expressed by stress is derived by using the strain energy function. The general fatigue life model is established by using the maximum logarithmic principal strain as the damage parameter. The finite element model of the thrust rod is established, and the stress distribution of the spherical hinge rubber layer and the easy damage area are analyzed. Based on the equivalent stress calculation results and the axial tension stress and strain data of the rubber material, the accuracy of the results of the finite element calculation is verified. By using the equivalent stress model, to predict the longitudinal fatigue life of V type thrust rod, prediction error than logarithmic maximum principal strain model, which shows that the equivalent stress as a composite damage parameter, compared to the maximum principal strain in one direction better reflect the fatigue characteristics of rubber material. The prediction error is within the allowable range of engineering, the results show that the method of fatigue life prediction based on the equivalent stress is correct, which can provide theoretical guidance for product development and engineering design.
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