Parametric study of the effect of wrinkle features on the strength of a tapered wind turbine blade sub-structure

Bender, J. J.; Hallett, Stephen R; Lindgaard, Esben

doi:10.1016/j.compstruct.2019.02.065

Cited by 31 publications

(22 citation statements)

References 13 publications

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“…These two different shapes were used to achieve wrinkles with varying maximum wrinkle angles. The resulting wrinkles were characterised in the same manner as described in [24], which means that the location, depth of effect, wash out degree, length, and height were defined for each wrinkle. These features are illustrated in Fig.…”

Section: Sub-structure Manufacturingmentioning

confidence: 99%

“…The length and height features are used to calculate the dependent maximum wrinkle angle, and the average wrinkle angle is calculated as in Eq. 1 [24].…”

Section: Sub-structure Manufacturingmentioning

confidence: 99%

“…The numerical FE model used in this work was developed as part of the work in [24], and therefore, thoroughly described therein. However, a brief overview of the main points of the FE model is included in the following.…”

Section: Numerical Modelsmentioning

confidence: 99%

“…6 Mesh of the FE model with a close-up at the wrinkle and tip of the tapered beam. [24] constructed, based on images of the manufactured sub-structures and fitting of the four features. The images were captured with a microscope set to x0.63 magnification, and a light source was placed on the back side of the sub-structure to transilluminate it.…”

Section: Numerical Modelsmentioning

confidence: 99%

“…This work is focused on experimentally quantifying the effect of a wrinkle defect in the vicinity of the termination of a tapered insert. In [24] it was determined that four features can be used to model a wrinkle and its shape through the thickness of a laminate. These features are the height of the wrinkle, the length of the wrinkle, the depth of effect or the number of affected plies, and the wash out degree, which is a measure for the height of the wrinkle through the thickness of the laminate.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of the effect of wrinkle features on wind turbine blade sub-structure strength

Bender¹,

Hallett²,

Lindgaard

2019

Composite Structures

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Wrinkles are known to have a strong knock-down on the mechanical performance of structures made from composite materials. Here, static tensile tests were conducted to investigate the effect of wrinkle features on the strength of a wind turbine blade sub-structure, representative of a blade root feature. A pultruded tapered insert is embedded in each sub-structure and the wrinkle is in close vicinity to the termination of the tapered insert. Each of the tested sub-structures was then numerically modelled using finite element simulations. The numerical representations of the wrinkle geometries were constructed based on measurements of the actual structures, and an automatic fitting of the four chosen wrinkle features; angle, depth, wash out, and location. There is less than 5% deviation between the simulation and experimental results for all tested sub-structures. The numerical model was able to predict when the failure mode changed from a delamination at the tapered insert to a delamination in the wrinkle area. The average wrinkle angle was found to be a better metric than the maximum wrinkle angle to characterise the severity of the wrinkles in the vicinity of a tapered insert.

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Section: Sub-structure Manufacturingmentioning

confidence: 99%

“…The length and height features are used to calculate the dependent maximum wrinkle angle, and the average wrinkle angle is calculated as in Eq. 1 [24].…”

Section: Sub-structure Manufacturingmentioning

confidence: 99%

Section: Numerical Modelsmentioning

confidence: 99%

Section: Numerical Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of the effect of wrinkle features on wind turbine blade sub-structure strength

Bender¹,

Hallett²,

Lindgaard

2019

Composite Structures

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A stiffness prediction method for variable cross‐section CFRP laminated beam

Yang,

Liu,

Zheng

et al. 2024

Polymer Composites

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To efficiently design the stiffness of the laminated composite blade‐like structure, an analytical method to assess deformation of variable cross‐section laminated beam under cantilever bending load was developed, in which a local ply density matrix method was introduced to characterize the ply‐up in arbitrary cross‐section after ply drop‐off process and infinitesimal element segment method was used to convert complex variable cross‐section specimen into local equal cross‐section beam structure. The model was validated by the cantilever beam experiment with relative predicted error of stiffness of 5.7%. Inner and outer ply drop‐off models were analyzed using the proposed analytical method. The results show that: (1) stiffness of the outer ply drop‐off model is the highest, at 13.07 N/mm, while that of the inner ply drop‐off model 2 is the lowest, about 17.8% lower than the outer ply drop‐off model; (2) maximum relative deformation difference between the inner ply drop‐off model 2 and outer ply drop‐off model is 21.7% at the free side of the cantilever beam. It indicates that anti‐deformation ability of the variable cross‐section laminated structure can be efficiently designed by the proposed analytical method, especially for the section close to the free side.Highlights Developed a bending stiffness prediction method for composite beam. Variable cross‐section feature of the composite laminate was considered. Local ply density matrix method was introduced to characterize ply drop‐off. Proposed method was validated by cantilever beam bending experiment. Inner and outer ply drop‐off models were compared by the proposed method.

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Predicting consolidation-induced wrinkles and their effects on composites structural performance

et al. 2019

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The majority of high-performance composite parts are nowadays designed using advanced numerical simulations that are able to accurately predict a part’s strength and deformation, providing that the internal ply architecture and exact fibre orientation are known with sufficient accuracy. However, most parts have some deviation of the fibre orientation from the ‘as-designed’ geometry, leading to the simulation overestimating the component’s strength. Up until recently, the advancement of the process simulation tools has not been sufficient to allow knowledge of this fibre deviation before any part has been manufactured, thus leading to overly conservative designs and costly experimental optimisation of the manufacturing process to reduce fibre path defects. This results in additional cost, waste of material and increased fuel consumption (due to the unnecessary weight of the components). This paper shows how state-of-the-art composite manufacturing simulations of the autoclave consolidation process can predict and help to mitigate against out-of-plane wrinkle formation in components made from toughened UD prepregs and thus raise confidence in failure analyses predictions. The industry relevant case of a stepped laminate is used as an example. Model predictions for the internal ply geometries are quantitatively compared to micrograph images of real samples. It is then shown how the input of the simulated ply architecture helps improving the accuracy of the failure simulations.

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Parametric study of the effect of wrinkle features on the strength of a tapered wind turbine blade sub-structure

Cited by 31 publications

References 13 publications

Investigation of the effect of wrinkle features on wind turbine blade sub-structure strength

Investigation of the effect of wrinkle features on wind turbine blade sub-structure strength

A stiffness prediction method for variable cross‐section CFRP laminated beam

Predicting consolidation-induced wrinkles and their effects on composites structural performance

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