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

重载车辆传动系统摩擦副在接合/分离过程中，摩擦片内齿与内毂外齿为啮合状态，由于动力输出的非平稳性，使得啮合齿部处于非线性高频冲击振动，其振动及冲击损伤特性将影响着传动系统的性能和使用寿命。为能正确预估高频冲击损伤对传动系统使用寿命的影响，对摩擦片齿部冲击碰撞应力变化规律和疲劳损伤理论的应用研究，提出了一种非线性冲击损伤计算的新算法。采用疲劳累积损伤原理和门槛值计算方法，分析了非线性冲击应力特性，引入了喷丸强化因子，并将代表当前损伤状态和应力状态对疲劳损伤发展影响的无量纲因子引进模型，得到了非线性冲击总损伤的数学模型。对摩擦副齿部进行了瞬态和稳态的应力试验测试，获得了1.5 mm齿侧间隙下10 s时间段的累积损伤值，利用新算法理论计算方法，推导了摩擦片全寿命周期总损伤值，获得了疲劳寿命预估值。经计算，其有效使用寿命周期为25.56 min。为对比不同边界条件下的损伤影响状态，对常用的不同齿侧间隙（0.75，1.25 mm）摩擦片齿部疲劳寿命进行了试验测试和总损伤值计算，分别获得了不同间隙条件下的使用寿命预估，其有效使用寿命分别为100.78，25.96 min。该方法能够通过实测应力状态，获得有效时间段累积损伤值，并通过计算，获得总损伤值及全寿命疲劳失效损伤的定量预估。该算法对摩擦片齿部高频冲击疲劳失效损伤的定量评价研究具有可操作的现实指导意义，也为进一步深入研究冲击碰撞损伤并准确量化研究奠定了理论基础。

A New Method of Non-linear Impact Damage and Fatigue Life Prediction on Meshing Teeth of High Energy Density Friction Pair

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.