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Buckling load analysis methods for rotor blade design

Objective



Objectives

The structural design of wind turbine components deals with static strength and with fatigue of the material. With increasing dimensions of wind turbines the increasing gravity loads and material costs result in a trend to material efficient designs. For rotor blades this is realised by using thin walled shell structures from fibre materials for which buckling becomes a design driver. From aerospace industry a lot of information is available on buckling which is mainly addressed to isotropic material and therefore does not always include specific aspects for wind turbine structures.
The objectives of the BUCKBLADE project is to improve the reliability of medium to small size wind turbine rotors by exploration of the existing knowledge of buckling prediction methods and transfer this knowledge to industry.

Technical Approach

An investigation is performed to the current knowledge by compiling a list of aspects that are considered or can be relevant for buckling and by making an overview of the buckling load prediction methods (tools or design rules) that are currently available. A number of publications on buckling load tests and calculations is collected from which the most representative are selected and used for evaluation of the prediction methods. Some tests on buckling of typical rotor blade constructions are performed on three test blades that are designed on buckling. The tests are addressed to provide specific information on buckling and to performing a buckling test. The results of these tests are used for further evaluation of the prediction methods in which two non-linear finite element codes suitable for this purpose will be involved.
The knowledge on buckling load predictions of rotor blades is further investigated by performing a set of sensitivity analysis on aspects (such as result from manufacturing) that have a serious influence on buckling.
Expected Achievements and Exploitation

The outcome will be a better understanding of the buckling phenomena as may occur in typical rotor blade constructions.
Reports will published reflecting information on the value and the interpretation of buckling load predictions by which design on buckling can be done with higher reliability. The reports include:
- State of the art on buckling load analysis for rotor blades, including a classification of tools and the aspects that are of relevance. - Results of performing buckling load tests.
- Design recommendations for prediction of the buckling load of rotor blade constructions.
The buckling load prediction tool that appears to be the most reliable and the most suitable for engineering application will be available for the European wind turbine industry.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

ENERGY RESEARCH CENTRE OF THE NETHERLANDS
Address
Westerduinweg 3
Petten
Netherlands

Participants (6)

Aerpac Special Products BV
Netherlands
Address
96,Bedrijvenpark Twente
7602 KD Almelo
GERMAN AEROSPACE CENTRE
Germany
Address
Pfaffenwaldring 38-40
70569 Stuttgart
LM Aero Construct GmbH Faserverbundtechnologie
Germany
Address
5,Industriestrasse
76891 Bundenthal
LM Glasfiber A/S
Denmark
Address
1,Rolles Moellevej
6640 Lunderskov
Lasso Ingenieurgesellschaft mbH
Germany
Address
11,Markomannenstrasse 11
70771 Leinfelden-echterdingen
STORK PRODUCT ENGINEERING BV
Netherlands
Address
229,Czaar Peterstraat 229
1000 AJ Amsterdam