Modelling and analysis of 2-stage planetary gear train for modular horizontal wind turbine application

Abstract

Wind turbine incorporates a gear box which aids the transmission of torque for the generation of wind energy, industry professionals have streamlined the gearbox design to suite this purpose. Despite the advancement in the gear box design, most wind turbine downtime is attributed to gearbox-related problems. In this study, Finite Element Method through ANSYS R15.0 software was employed in modelling and analysis of a 2-stage planetary gear train for modular horizontal wind turbine. The ring gear was considered as statically constrained member because it is practically fixed to the gearbox housing while the dynamics of the planet gear, planet carrier and the sun pinion were considered as rotating members. Using Factor of Safety (FOS) ranging from 10-15, the gear model was simulated to determine the equivalent stresses, strains and total deformation. The simulation which was conducted for five (5) steps at 2.5 seconds each yielded minimum and maximum Von-mises stress of 10.168 Pa and 5.9889e+009 Pa for the 5th step, minimum and maximum equivalent elastic strain of 5.0839e-011 and 2.9944e-002 for the 5th step and maximum total deformation of 1.7318e-003 m at the 5th step. The findings revealed that the higher the design FOS, the lower the stress-strain deformations, indicating longevity and optimum performance of the gear system. It was observed that increase in contact forces between the meshing gear teeth may cause larger elastic deformations, increasing tooth bending deformation as well as larger backlash on the gear teeth while continuously varying gear mesh stiffness with time can result in excessive vibration and noise.