高能摩擦副齿部啮合非线性冲击损伤新算法及疲劳寿命预测

During the engagement or detachment process of the friction pairs of a heavy-duty vehicle's transmission system, the internal gears of the friction plate and the external gears of the internal hub are in a meshing state. Due to the non-stationary power output, the meshing gears are subjected to non-linear high-frequency impact vibration. The vibration and impact damage characteristics will affect the performance and service life of the transmission system. To estimate the effects of high-frequency impact damage on the service life of the transmission system precisely, a new algorithm for the calculation of non-linear impact damage is proposed based on the application of the frictional stress variation rule and fatigue damage theory of the friction plate gears. The cumulative fatigue damage principle and numerical threshold methods were used to analyze the non-linear impact stress characteristics. The shot-peening factor, and a dimensionless factor representing the development effect of the current faulted condition and stress state on fatigue damage, were introduced into the model. Then, a mathematical model of the total non-linear impact damage was obtained. The transient and steady-state stress tests were carried out on the gears of the friction pairs, and the cumulative damage value was obtained for a period of 10 s under 1.5 mm of gear backlash. Using the new algorithm theory calculation method, the total damage value of the friction plate over its whole lifecycle was derived, and the estimation of fatigue life was obtained. According to the calculation, its effective service life is 25.56 min. To compare the damage effects under different boundary conditions, the fatigue life of the gears of friction plates with different gear backlash (0.75 mm and 1.25 mm) were tested, and the total damage value was calculated. The service life was then estimated under different clearance conditions. The effective service life is found to be 100.78 min and 25.96 min, respectively. This method obtains the cumulative damage value in the effective period by measuring the stress state and calculates the quantitative estimation of the total damage value and the fatigue failure damage throughout its lifecycle. The algorithm has practical guiding significance for the quantitative evaluation of high-frequency impact fatigue failure damage of the friction plate gears and lays a theoretical foundation for further in-depth study of impact damage and accurate quantitation research.