The vibration modes of a wind turbine support structure

Lightweight wind turbines offer a considerable reduction in capital and operating costs for electricity generation from the wind. Environmental impact of installation works can be reduced. Lightweight machines are likely to be structurally flexible. It is essential for the designer to study their dynamic characteristics in order to reduce:

1. The magnitude of the stresses in the structure particularly in components loaded cyclically;

2. The electrical noise and power fluctuation experienced by electricity consumers;

3. The acoustic noise emitted.

Using Rayleigh analysis, the vibration frequencies of a mathematical model of the wind turbine support tower can be estimated. Additional structural components can easily be added and components can be modelled more accurately as the process is refined.

Available experimental measurements compare favourably with corresponding predictions.