Contact fatigue failures are becoming increasingly prominent in heavy-duty gears due to the remarkable effects on service lives and reliabilities of associated machines such as wind turbines. The contact fatigue estimation of such gears is complicated due to the coupling effect of mechanical properties, lubrication and stochastic wind loadings. A numerical model was established to evaluate the contact fatigue damage evolution of a megawatt level wind turbine carburized gear pair based on the measured wind load spectrum. The elastohydrodynamic lubrication (EHL) theory was employed to compute the gear contact pressure and subsequently, the stress responses were obtained efficiently through the discrete convolute, fast Fourier transformation (DC-FFT) algorithm. The hardness and the residual stress gradients were captured via the Vickers hardness test and X-ray diffraction method, respectively. The Dang Van multiaxial fatigue criterion and the Basquin equation were adopted to estimate the fatigue lives under stochastic loadings, based on which the contact pressure-life curve was further profiled. Finally, the gear damage accumulation under this load spectrum was evaluated via the linear Palmgren-Miner rule. Results indicate that both the subsurface and transition area failures should be considered in gear design. The fatigue life prediction should consider the load spectrum rather than solely rely on a constant amplitude loading condition.

由于对耐用性的显着影响以及诸如风力涡轮机之类的相关机械的可靠性，在重型齿轮中接触疲劳故障变得越来越突出。由于机械性能，润滑和随机风载荷的耦合效应，这种齿轮的接触疲劳估计很复杂。建立了一个基于测得的风载荷谱评估兆瓦级风力涡轮渗碳齿轮副的接触疲劳损伤演变的数值模型。运用弹性流体动力润滑（EHL）理论计算齿轮的接触压力，然后通过离散卷积，快速傅立叶变换（DC-FFT）算法有效地获得了应力响应。分别通过维氏硬度测试和X射线衍射法捕获硬度和残余应力梯度。采用Dang Van多轴疲劳准则和Basquin方程估算随机载荷下的疲劳寿命，并在此基础上进一步绘制了接触压力-寿命曲线。最后，通过线性Palmgren-Miner规则评估了在此载荷谱下的齿轮损伤累积。结果表明，在齿轮设计中应同时考虑地下和过渡区域的破坏。疲劳寿命预测应考虑载荷谱，而不是仅依赖于恒定振幅载荷条件。采用Dang Van多轴疲劳准则和Basquin方程估算随机载荷下的疲劳寿命，并在此基础上进一步绘制了接触压力-寿命曲线。最后，通过线性Palmgren-Miner规则评估了在此载荷谱下的齿轮损伤累积。结果表明，在齿轮设计中应同时考虑地下和过渡区域的破坏。疲劳寿命预测应考虑载荷谱，而不是仅依赖于恒定振幅载荷条件。采用Dang Van多轴疲劳准则和Basquin方程估算随机载荷下的疲劳寿命，并在此基础上进一步绘制了接触压力-寿命曲线。最后，通过线性Palmgren-Miner规则评估了在此载荷谱下的齿轮损伤累积。结果表明，在齿轮设计中应同时考虑地下和过渡区域的破坏。疲劳寿命预测应考虑载荷谱，而不是仅依赖于恒定振幅载荷条件。