Mathematical modeling of gearbox including defects with experimental verification

A nine degree-of-freedom model of one stage gear system is presented in this research work. The gearbox structure is coupled with the vibration of the gear shaft. The model considers gear size, errors, and faults. The model includes varying meshing stiffness and a realistic representation of the gear transmission error (TE) and gear faults. Gear TE is modeled as a displacement excitation. The model equations are solved using Matlab and using parameters representing a real experimental gearbox rig. Experimental and simulated data are compared for different operating speeds, torque loads, and gear cracks. The simulation results are in good agreement with the experimental ones. The authors believe that the model presented here can be used in studying gear faults and would be very useful in developing gear fault monitoring techniques.