Wind Energy

Extended service life analysis for wind energy plants

The aim of the project, run by Germanische Lloyd Windenergie GmbH, is to develop an extended operational stability verification for forecasting the service life of wind energy plant components. This new economic method enables better utilisation of the potential for increasing plant reliability and cost optimisation thanks to lightweight design.

Summary

<xml></xml>Wind energy plants are becoming larger and more powerful with each successive generation. This is accompanied by optimisation of their components and their interaction. The intention of this research project is to develop an operational stability verification that makes better use of the information from simulated and measured loads than was previously the case and also takes account of innovations such as lightweight design.
The project partners are comparing calculations with measured loads to ultimately derive usable simplifications for the operational stability calculation method.
This results in a cost-effective method for forecasting component service life, which improves plant reliability and cost optimisation, while ensuring maintenance activities are more targeted than previously.
The authors of the individual reports are concentrating on specific critical components and recording the following results:
Screw connections:

  • The load on screws rises sharply due to imperfections when welding. Gaps that cannot be entirely closed are unacceptable and should be sealed with filler plates during assembly.

Screwed flange connections, machine:

  • A calculation for screw connections can often be carried out using finite element models (FEMs) at comparable cost to methods specified in directive VDI2230 but with more accurate results.

Screwed flange connections, tower:

  • Verification of L flange connections is being supplemented with calculation of imperfections on steel tube towers.

Cast structures:

  • For operational stability verification on semi-ductile cast structures, there is a good correspondence between normal stress theory and the cutting plant algorithm.
  • Methods using the ASME code achieve unrealistic results.
  • Grooves result in stress concentrations being channelled in one direction and thus reduce multi-axiality.

Welded connections:

  • The IIW verification concept appears to be more suitable than the local reference stress concept in Eurocode 3.

More Project Information

Project number: 0329860

Project period: 1999 - 2002

Project region: Germany (Hamburg)

Project contact:

Herr Dalhoff
This email address is being protected from spambots. You need JavaScript enabled to view it.
+49 (0) 40 36149-702

View Publication

Source: German National Library of Science and Technology Hannover (TIB)