Vibration analysis of nonlinear powertrain model with randomly cracked teeth under acyclism operation

Most of the researches works describe powertrain models under stationary operating conditions. However, the stationary assumption cannot always be true because during operation, the speed and the charge conditions are fluctuating. In this paper, dynamic behavior of nonlinear powertrain model under acyclism condition and the effect of cracked gear teeth on the dynamic response are investigated. The developed dynamic model considers the main components of the powertrain. The system is driven by a combustion engine through a clutch. The acyclism operation is caused by diesel engine generating torque, speed and gear mesh stiffness fluctuations. Moreover, the randomly cracked teeth of the gear are modeled by lowering the meshing stiffness. Using Runge Kutta 5th order method to solve the motion equations, time response and time-frequency representation are used to investigate the effect of acyclism and cracked teeth on dynamic behavior of the system. Simulation results show a simultaneous frequency and amplitude modulation due to acyclism and that gear defect lead to an increase in the vibratory level. Also, the presence of the characteristic impulses depends on the meshing of the cracked tooth.