Crack detection of a spur gear by frequency analysis of its vibration response

Vibration induced by gears includes important data about gearbox condition. We can use dynamic modeling of gear vibration for increasing our information about vibration generating mechanisms in gearboxes and dynamic behavior of gearbox in the presence of some kind of gear defects. In this paper a six degree-of-freedom nonlinear dynamic model including different gear errors and defects is developed for investigation of effects of tooth localized defect and profile modifications on overall gear dynamics.
Interactions between tooth modifications and profile error are studied and the role of profile modification in dynamic response when a localized defect is incurred by a tooth is shown. It is indicated that although profile modifications and profile errors are micro-geometrical, they have considerable effects on vibrations of gear pair. Especially for the case of root relieved teeth that is shown to be more effective in reduction of vibration in the presence of tooth localized defect. Finally, the simulation results are compared with results from literature and the model is verified.The model considered here, consists of a pair of spur gears on the two shafts that are connected to the load and prime mover. Torsional compliances of shafts and transverse compliances of bearings and consequently torsional and transverse vibrations of the gears along the line of action have been taken into account.