Calculation of Gear Mesh Stiffness of Cracked Dedendum via Energy Method
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摘要: 计算齿根具有裂纹的齿轮啮合刚度是求解含裂纹的齿轮传动系统动力学问题的基础。提出一种计及齿根裂纹表面自由能的计算齿轮啮合刚度的能量方法,该法将法向力作用下裂纹齿轮的弹性势能视为无裂纹齿轮的弹性势能与裂纹产生过程中释放的裂纹表面自由能之和。裂纹表面自由能通过裂纹应力强度因子与能量释放率之间的关系获得,齿根裂纹应力强度因子用权函数法求解。计算结果表明:齿根裂纹对齿轮啮合刚度影响很大;随着裂纹长度增加,裂纹齿轮啮合刚度减小,其求解结果与ANSYS软件计算结果一致。Abstract: To calculate the gear mesh stiffness with cracked dedendum is the key issue for solving the dynamic problem of the gear transmission system. An improved energy method considered the crack surface free energy release was proposed. The elastic potential energy of gear with cracked dedendum applied in the normal force on the tooth profile surface is regarded as the sum between the elastic potential energy of crack-free gear and the crack surface free energy released during the crack generation. The crack surface free energy was obtained according to the relationship between the stress intensity factors and the energy release rate of the crack. The stress intensity factors of the cracked dedendum was solved based on the weight function method. The calculation results reveal that the gear mesh stiffness is greatly influenced by the tooth root crack; the gear mesh stiffness decreases with the increasing of crack length. The calculation results are consistent with the ones in ANSYS software.
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表 1 参考载荷作用下裂纹应力强度因子多项式系数
γ0 γ1 γ2 γ3 γ4 γ5 γ6 γ7 1.121 5 -2.748 5 23.024 -108.34 282.21 -403.49 296.69 -88.319 表 2 齿轮几何参数及材料属性
参数 数值 参数 数值 弹性模量/GPa 200 齿宽/mm 20 泊松比 0.3 齿顶高系数 1.0 齿数 55/55 顶隙系数 0.25 模数/mm 5 重合度 1.77 压力角/(°) 20 表 3 能量法与有限元法刚度值对比
啮合点半径/mm 能量法/(N·m-1) 有限元法/(N·m-1) 相对误差/% 142.5 1.664×108 1.620×108 2.71 141.5 1.964×108 1.948×108 0.81 140.5 2.297×108 2.310×108 -0.54 139.5 2.660×108 2.678×108 -0.66 -
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