Delamination-Debond Behaviour of Composite T- Joints in Wind Turbine Blades

Gülaşık, Hasan; Çöker, Demirkan

doi:10.1088/1742-6596/524/1/012043

Cited by 8 publications

(4 citation statements)

References 19 publications

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“…The weak point of the composites used in the construction of the blades is that on the thickness of the composite the strength is ensured by the strength of the matrix. As presented in the literature, there are different sections and models of blade stiffening [ 16 , 17 , 18 , 19 , 20 ]. Some researchers [ 20 ] studied the problem of delamination of T-type joints between the cover and the stiffening elements inside the blade.…”

Section: Introductionmentioning

confidence: 99%

“…As presented in the literature, there are different sections and models of blade stiffening [ 16 , 17 , 18 , 19 , 20 ]. Some researchers [ 20 ] studied the problem of delamination of T-type joints between the cover and the stiffening elements inside the blade. According to other researchers [ 21 , 22 , 23 , 24 , 25 , 26 , 27 ], the delamination mechanism consists of separation of plies from each other under loading.…”

Section: Introductionmentioning

confidence: 99%

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Prediction of the Damage Effect on Fiberglass-Reinforced Polymer Matrix Composites for Wind Turbine Blades

2022

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The structure of wind turbine blades (WTBs) is characterized by complex geometry and materials that must resist various loading over a long period. Because of the components’ exposure to highly aggressive environmental conditions, the blade material suffers cracks, delamination, or even ruptures. The prediction of the damage effects on the mechanical behavior of WTBs, using finite element analysis, is very useful for design optimization, manufacturing processes, and for monitoring the health integrity of WTBs. This paper focuses on the sensitivity analysis of the effects of the delamination degree of fiberglass-reinforced polymer composites in the structure of wind turbine blades. Using finite element analysis, the composite was modeled as a laminated structure with five plies (0/45/90/45/0) and investigated regarding the stress states around the damaged areas. Thus, the normal and shear stresses corresponding to each element of delaminated areas were extracted from each ply of the composites. It was observed that the maximum values of normal and shear stresses occurred in relation to the orientation of the composite layer. Tensile stresses were developed along the WTB with maximum values in the upper and lower plies (Ply 1 and Ply 5), while the maximum tensile stresses were reached in the perpendicular direction (on the thickness of the composite), in the median area of the thickness, compared to the outer layers where compression stresses were obtained. Taking into account the delamination cases, there was a sinuous-type fluctuation of the shear stress distribution in relation to the thickness of the composite and the orientation of the layer.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Prediction of the Damage Effect on Fiberglass-Reinforced Polymer Matrix Composites for Wind Turbine Blades

2022

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“…Othman et al [6] and Robert et al [7] proposed methods for detecting and testing the interlaminar debonding and delamination damage of wind turbine blades. Hasan et al [8] conducted a debonding analysis on the T-joints of wind turbine blades, and Ji et al [9] developed a fracture mechanics approach for the failure of the joints of wind turbine blades. In this research, the test data for Mode II, that is, the sliding mode, were acquired, and the CZM method of the spar-web joint area was used to propose a methodology for the initiation and growth of the debonding damage in wind turbine blades.…”

Section: Introductionmentioning

confidence: 99%

Progressive Failure Analysis for 5MW-Class Wind Turbine Composite Blades with Debonding Damage based on CZM Method

2022

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Composite wind turbine blades may experience interlaminar damage, including adhesive failure, cracking, and interlaminar fracture failure, from manufacturing or external fatigue load. Among these, the adhesive failure of adhesive joints is critical. Therefore, it is important to identify the failure mechanism in the adhesive joints between the spar cap–shear web and trailing edge of composite blades. We calculated fracture toughness through Mode I, Mode II, and Mixed-mode tests for quantitative analysis of adhesive joints. Then, to select a modeling method for realizing the damage generated in the blade, the method was verified from the specimen level. A damage model was constructed, considering contact conditions of the spar cap–shear web and trailing edge for an NREL 5MW wind turbine blade. Finally, a damage model based on cohesive zone modeling was used to analyze the progressive failure behavior of debonding at adhesive joints according to the external force applied to the blade.

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“…The delamination onset was determined based on the the specific angle at which the maximum average shear stress occurred at the ply interface in a cross-ply [0 [14]. The failure analysis of T-shaped skin-stiffener composites was particularly studied in [16][17][18][19][20][21] under pull-off loading and the delamination failure mode was determined experimentally and numerically. In [16] it was shown that the failure initiated in the vertical stiffener due to Mode-I splitting cracks and Mode-I/II pin traction loads controlled the ultimate strength of the T-joint.…”

Section: Introductionmentioning

confidence: 99%

Assessment of failure and cohesive zone length in co-consolidated hybrid C/PEKK butt joint

Baran

Warnet

Akkerman

2018

Engineering Structures

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The failure mechanisms and the cohesive zone length (CZL) during fracture of recently developed butt jointed thermoplastic composite are evaluated in this paper. The laminated skin and the web were made of AS4/PEKK. The butt joint (filler) was injection molded from 20 % short AS4 filled PEKK. The skin and web were co-consolidated together with the filler to form a hybrid butt joint structure. The crack initiation and propagation in the filler and the delamination at the skin-filler interface were captured using a high-speed camera. It was found from the experimental observations that the crack initiated in the filler and then propagated towards the skin-filler interface in less than 33 µs under three-point bending. A numerical model was developed using the finite element method in ABAQUS to predict the failure and CZL. The crack initiation and progression in the filler was predicted using the Virtual Crack Closure Techniques (VCCT) and the delamination at the skin-filler interface was modelled using the cohesive surfaces. The predicted stiffness of the specimen, the location of crack initiation and propagation as well as the force drop during delamination were in good agreement with experiments. The development of CZL was critically assessed and it was found that the CZL increases during delamination. The effect of interface strength and critical energy release rate on the CZL was investigated in the parameter analysis.

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Delamination-Debond Behaviour of Composite T- Joints in Wind Turbine Blades

Cited by 8 publications

References 19 publications

Prediction of the Damage Effect on Fiberglass-Reinforced Polymer Matrix Composites for Wind Turbine Blades

Prediction of the Damage Effect on Fiberglass-Reinforced Polymer Matrix Composites for Wind Turbine Blades

Progressive Failure Analysis for 5MW-Class Wind Turbine Composite Blades with Debonding Damage based on CZM Method

Assessment of failure and cohesive zone length in co-consolidated hybrid C/PEKK butt joint

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