Building Delamination Fracture Envelope under Mode I/Mode II Loading for FRP Composite Materials

Al-Khudairi, O.; Hadavinia, H.; Lewis, E.C. Ii; Osborne, Barnaby; Bryars, Lee S.

doi:10.1002/9781118535288.ch12

Cited by 1 publication

(1 citation statement)

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“…The rest of the blade is usually constructed from multi-axial skin material and sandwich structure from glass fibre reinforced polymer (GFRP) composite layers, with a core from foam or balsa wood, ensuring low mass, resistance to torsion and buckling. Characterisation of GFRP materials prior to using in the blade is necessary and the procedure for determining delamination toughness and fatigue performance of GFRP have been reported elsewhere [ 3 , 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

Full-Scale Fatigue Testing of a Wind Turbine Blade in Flapwise Direction and Examining the Effect of Crack Propagation on the Blade Performance

et al. 2017

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In this paper, the sensitivity of the structural integrity of wind turbine blades to debonding of the shear web from the spar cap was investigated. In this regard, modal analysis, static and fatigue testing were performed on a 45.7 m blade for three states of the blade: (i) as received blade (ii) when a crack of 200 mm was introduced between the web and the spar cap and (iii) when the crack was extended to 1000 mm. Calibration pull-tests for all three states of the blade were performed to obtain the strain-bending moment relationship of the blade according to the estimated target bending moment (BM) which the blade is expected to experience in its service life. The resultant data was used to apply appropriate load in the fatigue tests. The blade natural frequencies in flapwise and edgewise directions over a range of frequency domain were found by modal testing for all three states of the blade. The blade first natural frequency for each state was used for the flapwise fatigue tests. These were performed in accordance with technical specification IEC TS 61400-23. The fatigue results showed that, for a 200 mm crack between the web and spar cap at 9 m from the blade root, the crack did not propagate at 50% of the target BM up to 62,110 cycles. However, when the load was increased to 70% of target BM, some damages were detected on the pressure side of the blade. When the 200 mm crack was extended to 1000 mm, the crack began to propagate when the applied load exceeded 100% of target BM and the blade experienced delaminations, adhesive joint failure, compression failure and sandwich core failure.

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Section: Introductionmentioning

confidence: 99%