Vibration Characteristic Analysis of Cracked Gear Based on Time-varying Meshing Stiffness

Under complex working conditions, the gear system is prone to crack failure, which makes it difficult for normal operation. Time-varying meshing stiffness is one of the important internal incentives of gear transmission system. The change of stiffness can well reflect the dynamic response of gear. Therefore, using an accurate stiffness algorithm can effectively analyze the dynamic characteristics of gear system. Considering the function of gear transition curve, the potential energy method is used to calculate the time-varying meshing stiffness of gear by analyzing the complete profile curve, and the stiffness changes of 10 different crack lengths are studied. Considering the time-varying mesh stiffness and sliding friction between teeth, a dynamic gear model with six degrees of freedom is established. The dynamic response of gear with different crack lengths is simulated by Runge-Kutta method. By analyzing the displacement response, it is found that the impact characteristics will occur when there is a crack in the gear. With the increase of the crack length, the impact characteristics become more and more obvious. Finally, the trends of various statistical indicators with respect to the level of crack extension are compared and analyzed. The results show that the kurtosis indicator is the most sensitive to fault characteristics.