A Physical Model based research for fault diagnosis of gear crack

Because of the advantage of gear, gearbox was used widely. But its fault also brought many losses of the production and society. It was necessary to research and analysis on the dynamical behavior of the gear system. One kind of gear fault was numerically simulated so that the influence of gear fault to change of vibration state was studied theoretically, and the symptom generated by faults was found. A finite element model with crack in gear roots was established with mixed meshing of singularity and isoparametric elements. The automatic analysis program of crack propagation was developed based on the ABAQUS software and linear elasticity fracture mechanics. The crack propagation of involutes´ gear was simulated. The structural experiments of fault crack with different types and sizes were done, the vibration signals of the fault gear body and system were tested, and the dynamical characteristics of the structure and system were gained. The results were compared to that of simulation and theory, the validity of the theoretic and simulative was testified and the reliability was proved. There was important guidance for predicting the residual life of the gear with crack.