齿轮齿根疲劳裂纹扩展特性和剩余寿命研究

以某渐开线圆柱齿轮为对象,基于有限元法对其齿根疲劳裂纹的扩展进行了数值模拟。首先通过对一对健康齿的啮合分析确定其啮合过程中齿根部位弯曲应力最大点,并将其作为裂纹起始点。据此将其分割为裂纹块和非裂纹块。在裂纹块预制初始裂纹并重生网格,裂纹块网格采用等参奇异单元,裂纹块和非裂纹块之间通过多点约束连接不匹配节点。利用有限元分析得到裂纹扩展过程中应力强度因子变化情况,并根据最大周向应力准则计算疲劳裂纹扩展角度,模拟齿根裂纹扩展轨迹,依据Paris公式对齿根疲劳裂纹剩余寿命进行预估。分析了载荷大小和初始裂纹长度对剩余寿命的影响。

RESEARCH ON FATIGUE CRACK PROPAGATION CHARACTERISTICS AND REMAINING LIFE AT THE TOOTH ROOT OF A GEAR

Based on the FEM,the fatigue crack propagation of a involute cylindrical gear is numerically simulated.Firstly,through analyzing the meshing gear of a pair of healthy teeth,the maximum bending stress of the tooth root is determined,And it is taken as the starting point of the crack.The cracks are divided into crack and non crack blocks.The initial crack is preformed in the crack block and the block is remeshed with isoparametric singular element.The crack block and the non cracked block is connected by a multi-point constraint.The stress intensity factor and crack propagation angle are measured in crack propagation process,Based on Paris formula,tooth crack propagation trajectory and remaining life of gear is numerically simulated.The influence of load as well as initial crack length on residual life was analyzed.