Drivetrain and Gearbox Modelling Tools and Analysis Process
Dynamic analysis of the entire system is done using Ricardo's dynamic analysis code VALDYN. Finite element models of the housings and tower can be used to support the dynamic model. This itself includes finite element models of the shafts, rolling element bearings and contact models of the gears. As this is a time domain solution, the effect of the dynamic response of the system is coupled with the excitation of the drivetrain forces.
Shaft and bearing analysis is critical in understanding the behaviour of a gearbox.
Wind turbine gearboxes are subjected to very high torques, significantly varying loads, with a large emphasis on reducing weight which has to be supported at the top of the tower.
Quasi-static analysis can be used initially both for concepting and problem solving. Ricardo's shaft and bearing analysis software, SABR, is used to understand the loading conditions within a gearbox.
Critical results for the performance of the gearbox are assessed including:
- Multi-load duty cycle including overload and inertia backdriving
- Bearing damage
- Shaft stress and stress concentrations
- Effect of preload on bearing life
- Effect of relative shaft position on bearing load and size
- Effect of housing deflection on shaft misalignment and bearing life
- Effect of gear misalignment on gear life and stress.