Fatigue testing of a 14.3 m composite blade embedded with artificial defects – Damage growth and structural health monitoring

Xiao, Chen; Semenov, Sergei; McGugan, Malcolm; Madsen, S.; Yeniceli, Süleyman Cem; Berring, Peter; Branner, Kim

doi:10.1016/j.compositesa.2020.106189

Cited by 47 publications

(45 citation statements)

References 22 publications

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“…This allows for an exceptionally detailed and thorough validation. Unlike other blade tests reported in literature (Chen et al, 2021(Chen et al, , 2017Jensen et al, 2006;Overgaard and Lund, 2010;, the aim of the tests in this work is not the validation of failure models. Hence, the blade is not loaded up to failure.…”

Section: Objectives Of This Papermentioning

confidence: 99%

Validation of a modeling methodology for wind turbine rotor blades based on a full-scale blade test

2022

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Abstract. Detailed 3D finite-element simulations are state of the art for structural analyses of wind turbine rotor blades. It is of utmost importance to validate the underlying modeling methodology in order to obtain reliable results. Validation of the global response can ideally be done by comparing simulations with full-scale blade tests. However, there is a lack of test results for which also the finite-element model with blade geometry and layup as well as the test documentation and results are completely available. The aim of this paper is to validate the presented fully parameterized blade modeling methodology that is implemented in an in-house model generator and to provide respective test results for validation purpose to the public. This methodology includes parameter definition based on splines for all design and material parameters, which enables fast and easy parameter analysis. A hybrid 3D shell/solid element model is created including the respective boundary conditions. The problem is solved via a commercially available finite-element code. A static full-scale blade test is performed, which is used as the validation reference. All information, e.g., on sensor location, displacement, and strains, is available to reproduce the tests. The tests comprise classical bending tests in flapwise and lead–lag directions according to IEC 61400-23 as well as torsion tests. For the validation of the modeling methodology, global blade characteristics from measurements and simulation are compared. These include the overall mass and center of gravity location, as well as their distributions along the blade, bending deflections, strain levels, and natural frequencies and modes. Overall, the global results meet the defined validation thresholds during bending, though some improvements are required for very local analysis and especially the response in torsion. As a conclusion, the modeling strategy can be rated as validated, though necessary improvements are highlighted for future works.

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Section: Objectives Of This Papermentioning

confidence: 99%

Validation of a modeling methodology for wind turbine rotor blades based on a full-scale blade test

2022

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“…24 PSD based on the Fourier transform was computed for the standardized strain signal matrix from Equation 2 for all the strain portions separately, and a modal fit of the PSD was performed in Matlab with a command modalfit, choosing to extract the first two eigenfrequencies (the 1st flapwise and the 1st edgewise). Apart from the time history signal, the modalfit command requires to set the frequency bandwidth, sampling frequency (20 Hz), curvefitting method, and the frequency range of interest (from 0 to 6 Hz, since the estimated values of the 1st flapwise and the 1st edgewise natural frequencies are 2.30 and 4.65 Hz, respectively 19 ). The fitting method was chosen as least squares complex exponential (LSCE).…”

Section: Strain Featuresmentioning

confidence: 99%

Control of damage‐sensitive features for early failure prediction of wind turbine blades

Janeliukštis

McGugan

2021

Structural Contr & Hlth

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“…It was found that delamination close to the blade surface leads to local buckling modes and is more critical than delamination near the mid surface in the spar. Other bladespecific damage tolerance studies can be found in [7,[20][21][22][23][24]. There are also records of impact damage tolerance studies for thin-walled composite structures applications in other industries, such as aerospace, aircraft, automotive, and civil.…”

Section: Literature Review: Wind Turbine Blades Impact Loads and Dama...mentioning

confidence: 99%

Bondline Thickness Effects on Damage Tolerance of Adhesive Joints Subjected to Localized Impact Damages: Application to Leading Edge of Wind Turbine Blades

et al. 2021

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The leading edges of wind turbine blades are adhesively bonded composite sections that are susceptible to impact loads during offshore installation. The impact loads can cause localized damages at the leading edges that necessitate damage tolerance assessment. However, owing to the complex material combinations together with varying bondline thicknesses along the leading edges, damage tolerance investigation of blades at full scale is challenging and costly. In the current paper, we design a coupon scale test procedure for investigating bondline thickness effects on damage tolerance of joints after being subjected to localized impact damages. Joints with bondline thicknesses (0.6 mm, 1.6 mm, and 2.6 mm) are subjected to varying level of impact energies (5 J, 10 J, and 15 J), and the dominant failure modes are identified together with analysis of impact kinematics. The damaged joints are further tested under tensile lap shear and their failure loads are compared to the intact values. The results show that for a given impact energy, the largest damage area was obtained for the thickest joint. In addition, the joints with the thinnest bondline thicknesses displayed the highest failure loads post impact, and therefore the greatest damage tolerance. For some of the thin joints, mechanical interlocking effects at the bondline interface increased the failure load of the joints by 20%. All in all, the coupon scale tests indicate no significant reduction in failure loads due to impact, hence contributing to the question of acceptable localized damage, i.e., damage tolerance with respect to static strength of the whole blade.

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Fatigue testing of a 14.3 m composite blade embedded with artificial defects – Damage growth and structural health monitoring

Cited by 47 publications

References 22 publications

Validation of a modeling methodology for wind turbine rotor blades based on a full-scale blade test

Validation of a modeling methodology for wind turbine rotor blades based on a full-scale blade test

Control of damage‐sensitive features for early failure prediction of wind turbine blades

Bondline Thickness Effects on Damage Tolerance of Adhesive Joints Subjected to Localized Impact Damages: Application to Leading Edge of Wind Turbine Blades

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