Development and design of elastic, rubber-based components in order to mounting various units along the power train of wind turbines

Introduction

Vibrations and noise represent an important technical topic for modern windmills. Legal requirements, ecological aspects or technical issues such as durability require a detailed estimation, evaluation, and partially reduction of occurring excitations and vibrations e. g. along the power train. For this reason so-called Rubber-To-Metal parts (RTMs) are widely used in windmills. However, the materials behavior of rubber significantly differs to metals and, consequently many engineers feel unsure during designing and dimensioning of RTMs, especially under the impression of the occurring, considerable loads.

Approach

Typical RTMs found in a windmill are coupling elements and mountings. Here rubber is used to compensate displacements and torque oscillations of the drive shaft, or to decouple structure born noise e.g. between the power train and the frame structure. Especially for rotor, gear box, generator, control units or nacelle one can find rubber-based mounts.
Starting with a brief overview of typical designs for mounting concepts this contribution will schematically illustrates, which materials aspects and calculations approaches are required to develop RTMs.

Main body of abstract

In particular the following items are considered:

- Overview of rubber and its materials behavior (aging, Payne and Mullins effect, Non-linearities, etc.),

- Fundamentals of vibration control (isolation, damping, resonance, etc.),

- Designing RTM parts with focus on life-time estimation (Woehler and Smith-Haigh Diagrams) as well as loading and isolation demands,

- Hydraulic damping mounts.


Conclusion

The present contribution illustrates different aspects of Vibration Control components within windmills. The requirement for vibration control and acoustics are motivated and different, widely used design concepts are presented. The main materials properties of rubber are considered and discussed. Finally, typical engineering approaches are presented that allows to develop rubber-based components.


Learning objectives