直齿轮弯曲疲劳裂纹的扩展行为预测与分析

Prediction and Analysis of Bending Fatigue Crack Growth Behavior of Spur Gear

以渐开线圆柱齿轮为研究对象,在其齿根部存在初始裂纹的前提下,研究齿根疲劳裂纹扩展特性及其寿命;将齿轮啮合过程的动力学计算等效为多个啮合位置的静力分析,得到不同位置的应力强度因子;根据线弹性断裂力学,将裂纹扩展过程线性等效,以K判据分析裂纹是否发生扩展,根据Paris准则计算裂纹扩展量,采用最大周向应力准则确定裂纹扩展角度,得到整个计算周期的应力强度因子、疲劳裂纹扩展路径及疲劳寿命;采用高频试验台对齿轮进行疲劳试验,得到齿轮的疲劳扩展路径,与有限元计算结果进行对比验证;最后分别分析了初始裂纹的尺度、位置和载荷的不同对疲劳裂纹的扩展及疲劳寿命的影响。

Based on the involute cylindrical gear as research object,the initial premise of the existence of cracks on the tooth root,the root of the fatigue crack growth characteristics and life are studied. The dynamics calculation of the gears meshing is equivalent to multiple engagement position static analysis,the stress intensity factors at different positions are obtained. According to the linear elastic fracture mechanics, the linear equivalent of crack growth is carried out,by using K criterion to analyze whether the crack extend. According to the Paris criterion to determine the amount of crack growth,using the maximum circumferential stress criterion to determine the crack growth angle,the stress intensity factor,crack growth path and fatigue life of the calculation cycle are obtained. By using high frequency test bench,the fatigue tests are carried out on the gear,the gear fatigue the expansion path is got,and comparing with the results of finite element calculation results.Finally,the influence of different initial crack size,position and load on fatigue crack growth and fatigue life is analyzed.