中文摘要：

用有限元方法模拟圆柱齿轮齿根处疲劳裂纹的扩展过程.分析齿轮中疲劳裂纹的扩展路径和扩展形貌,依此设定合适的寿命积分路径,对齿轮的疲劳寿命进行预测,分析初始裂纹倾角对齿轮中疲劳裂纹的扩展形貌以及齿轮疲劳寿命的影响.结果表明：萌生于齿根处的疲劳裂纹,在齿廓面上朝着齿顶方向倾斜扩展,在齿端面上,从一侧齿根以圆弧状的扩展路径朝着对侧齿根扩展;对于相同的初始裂纹深度,初始裂纹的倾角较大,齿轮易发生轮缘断裂,其疲劳寿命相对较长,相反,初始裂纹的倾角较小,齿轮易发生齿根断裂,其疲劳寿命相对较短.

英文摘要：

Propagation process of fatigue crack initiated at-tooth root of cylindrical gear is simulated by using finite element method. The propagation path and morphology of fatigue crack in the gear is analyzed and on its basis, an appropriate life integral path is set up, the gear fatigue life is predicted, and the influence of inclination angle of initial crack at tooth root on crack propagation morphology and fatigue life of cylindrical gear is analyzed. The result shows that the initiate fatigue crack at tooth root will obliquely propagate toward the tooth tip on the gear tooth profile face; it will propagate on the end-face of the tooth from one tooth root toward its adjacent tooth root in the form of circular arc as crack propagation path. In the case of identical initial crack depth, the gear rim fracture will easily occur when the inclination angle of the initial crack is bigger and the gear will have a relatively longer fatigue life. In contrast, the gear tooth fracture will easily occur when the inclination angle of the initial crack is smaller and the gear will have a relatively shorter fatigue life.