Dynamics of wind turbines including soil-structure interaction

Abstract

This thesis investigates the dynamic response of Horizontal Axis Wind Turbines (HAWT) including Soil-Structure Interaction (SSI) effects. Multi- Degree-of-Freedom (MDOF) HAWT models are proposed for dynamic analysis using an Euler-Lagrangian approach including foundation inter-action. Two distinct models are developed: an out-of-plane model and a coupled in-plane out-of-plane model. The out-of-plane model comprises of a rotor blade system, a nacelle and a flexible tower connected to a foundation system using a substructuring approach. The rotor blade system consists of three rotating blades and includes the effect of centrifugal stiffening due to rotation. The coupled in-plane out-of-plane model is extended to include in-plane motion for the blade, tower and foundation and for the roll, tilt, yaw and drivetrain nacelle DOFs.