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INVESTIGATION OF THE FATIGUE PROPERTIES OF AERO-GENERATOR STRUCTURAL MATERIALS.

Objective

SET UP OF A COMPREHENSIVE BODY OF KNOWLEDGE ON FATIGUE PROPERTIES OF COMMON MATERIALS FOR WIND TURBINE BLADES.
Fatigue tests on coupon specimens and on full scale components made of glassfibre reinforced polyester have been carried out. This material is widely used in the construction of rotor blades.
THE APPLICATION OF COMPOSITE MATERIALS IN THE CONSTRUCTION OF ROTORBLADES IS VERY COMMON TODAY. IN THE PRESENT WORK THIS MATERIAL WILL BE INVESTIGATED FROM THE POINT OF VIEW OF FATIGUE - AND STIFFNESS PROPERTIES IN THE HIGH CYCLE FATIGUE RANGE. IN THE RUG-PROJECT THE INVESTIGATIONS ARE LIMITED TO GLASS FIBER REINFORCED POLYESTER OF +/- 10 DEGREES C. FIBER ORIENTATION AT THREE DIFFERENT TEMPERATURES : - 20, + 20, AND + 50 DEGREES C. CONSTANT STRESS AMPLITUDE TESTS ARE PERFORMED FOR TWO STRESS RATIOS : R = 0.1 AND R = -1. AT LEAST 16 TESTS ARE CARRIED OUT FOR A GIVEN TEST CONDITION IN ORDER TO GENERATE SETS OF DATA WITH SOME STATISTICAL VALUE. IT IS ASSUMED THAT E-N CURVES CAN BE WRITTEN AS A POWER-LAW.

THE DATA SET IS ANALYSED BY MEANS OF A DATA POOLING TECHNIQUE. THE BEST ESTIMATE OF THE SHAPE PARAMETER OF A TWO-PARAMETER WEIBULL DISTRIBUTION IS ACHIEVED BY A MAXIMUM LIKELIHOOD METHOD. SOME RESULTS ARE PRESENTED (R = 0.1 AT - 20 DEGREES C. AND AT + 20 DEGREES C.).

THE OTHER TOPIC IN THE RUG-PROJECT IS LARGE SCALE BLADE TESTING. SUCH TESTS ARE NEEDED TO VERIFY REAL STRUCTURE BEHAVIOUR ON THE BASIS OF RESULTS OF COUPON TESTS. THREE ROOT SECTIONS OF ROTORBLADES ARE TESTED AND FOUR OTHERS HAVE TO BE TESTED. SOME RESULTS ARE PRESENTED OF A TEST ON A D-SPAR OF NEW DESIGN.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

GENT UNIVERSITY
Address
Sint Pietersnieuwstraat 25
9000 Gent
Belgium

Participants (1)

VRIJE UNIVERSITEIT VAN BRUSSEL (VUB)
Belgium
Address

Prof. Hirsch