Effects of bedplate flexibility on drivetrain dynamics: Case study of a 10 MW spar type floating wind turbine

Abstract

This paper deals with the effect of bedplate flexibility on drivetrain dynamics of a 10 MW spar type floating wind turbine. The 10 MW drivetrain bedplate is designed based on extreme design loads and ultimate limit state (ULS) design criteria. A decoupled analysis approach is employed. Global dynamic analysis of the 10 MW floating turbine is firstly conducted using an aero-hydro-servo-elastic code, then the global response is used as input to the drivetrain dynamic analysis. Load effects and fatigue damage of gears and bearings in the rigid and flexible bedplate models in different environmental conditions are compared. In addition, sensitivity of the drivetrain fatigue damage to varying fidelity in the bedplate modelling is studied. The results indicate that the bedplate flexibility would increase the load effects on bearings inside the gearbox, while it would reduce the load effects on the main bearings. Reasonable bedplate modelling fidelity is of great importance, because it could save a great deal of computational costs without loss of the drivetrain dynamic response accuracy. The present work provides a reference for a proper drivetrain design and dynamic analysis in the future, by accounting for bedplate flexibility.