We study the kinetics of propagation of fatigue cracks on the surface of side frame of a rail car with regard for the stochastic nature of the operating load. Its dependence on the initial geometry of the crack is established. Moreover, under given loading conditions, we determine the shape of semielliptic contour of the fatigue crack characterized by the highest growth rate into the depth of the frame wall. We also formulate a mathematical model suitable for the evaluation of the residual service life of the side frame containing a surface cracklike defect with given initial area.

中文翻译：

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不规则工作载荷下货运转向架侧架表面疲劳裂纹的扩展

我们研究了轨道车侧架表面疲劳裂纹的传播动力学，并考虑了操作载荷的随机性。它依赖于裂纹的初始几何形状。此外，在给定的载荷条件下，我们确定了疲劳裂纹的半椭圆轮廓形状，其特征是框架壁深度的最高增长速率。我们还制定了一个数学模型，适用于评估包含具有给定初始面积的表面裂纹状缺陷的侧框架的剩余使用寿命。