Dynamic impact modeling and analysis of the floating-supported friction plate and inner hub system considering tooth root cracks

Under sustained strong stochastic impact loads, floating-supported friction plates are susceptible to the formation of fatigue cracks that propagate along the rim. The nonlinearity and randomness introduced by the cracked teeth participating in the impacts significantly influence the service life and reliability of the transmission system. In this paper, an improved stiffness excitation modeling method is developed for friction plate teeth with rim cracks. It overcomes the limitations of traditional approaches that fail to accurately assess the narrow-band, large-diameter friction plate teeth with rim cracks due to constraints imposed by boundary conditions. Then, an original dynamic impact model for the floating-supported friction plate and inner hub system is proposed, incorporating the effects of bending-torsional-axial-tilting coupled motions on tooth mesh excitations and dynamic responses. This model addresses the limitations of conventional models that only consider bending-torsion coupling, thereby providing a more comprehensive representation of the system’s multi-dimensional dynamic behavior. The effects of the crack propagation depth and the number of cracked teeth on the stochastic impact characteristics and vibration responses of the system are investigated. Furthermore, finite element simulations and experimental tests are conducted to validate the cracked tooth stiffness excitations and dynamic impact responses, respectively. The proposed model is anticipated to provide both a theoretical foundation and practical guidance for fault diagnosis and reliability assessment of clutch friction plates.