Characterization of Manufacturing Defects Common to Composite Wind Turbine Blades: Flaw Characterization

2011 ◽  
Author(s):  
Trey Riddle ◽  
Douglas Cairns ◽  
Jared Nelson
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Manufacturing Defects ◽  
Flaw Characterization

scholarly journals Probabilistic Design of Wind Turbine Blades with Treatment of Manufacturing Defects as Uncertainty Variables in a Framework

2017 ◽  
Author(s):  
Trey W. Riddle ◽  
Jared W. Nelson ◽  
Douglas S. Cairns
Keyword(s):  
Wind Turbine ◽  
Probabilistic Models ◽  
Low Cost ◽  
Turbine Blades ◽  
Design Parameters ◽  
State University ◽  
Wind Turbine Blades ◽  
Manufacturing Defects ◽  
Montana State University ◽  
Blade Failure

Abstract. Given that wind turbine blades are such large structures, the use of low-cost composite manufacturing processes and materials has been necessary for the industry to be cost competitive. Since these manufacturing methods can lead to inclusion of unwanted defects, potentially reducing blade life, the Blade Reliability Collaborative tasked the Montana State University Composites Group with assessing the effects of these defects. Utilizing the results of characterization and mechanical testing studies, probabilistic models were developed to assess the reliability of a wind blade with known defects. As such, defects were found to best be assessed as design parameters in a parametric probabilistic analysis allowing for establishment of a consistent framework to validate categorization and analysis. Monte Carlo simulations were found to adequately describe the probability of failure of composite blades with included defects. By treating defects as random variables, the approaches utilized indicate the level of conservation used in blade design may be reduced when considering fatigue. In turn, safety factors may be reduced as some of the uncertainty surrounding blade failure is reduced when analysed with application specific data. Overall, the results indicate that characterization of defects and reduction of design uncertainty is possible for wind turbine blades.

Damage mitigation techniques in wind turbine blades: A review

2017 ◽  
Vol 41 (3) ◽  
pp. 185-210 ◽  
Author(s):  
Md Abu S Shohag ◽  
Emily C Hammel ◽  
David O Olawale ◽  
Okenwa I Okoli
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Structural Elements ◽  
Variable Loading ◽  
Wind Turbine Blades ◽  
Lightning Strikes ◽  
Manufacturing Defects ◽  
Damage Mitigation ◽  
Mitigation Techniques ◽  
Operational Errors

Wind blades are major structural elements of wind turbines, but they are prone to damage like any other composite component. Blade damage can cause sudden structural failure and the associated costs to repair them are high. Therefore, it is important to identify the causation of damage to prevent defects during the manufacturing phase, transportation, and in operation. Generally, damage in wind blades can arise due to manufacturing defects, precipitation and debris, water ingress, variable loading due to wind, operational errors, lightning strikes, and fire. Early detection and mitigation techniques are required to avoid or reduce damage in costly wind turbine blades. This article provides an extensive review of viable solutions and approaches for damage mitigation in wind turbine blades.

Nonlinear aeroelastic characterization of wind turbine blades

2014 ◽  
Vol 22 (3) ◽  
pp. 621-631 ◽  
Author(s):  
Y Bichiou ◽  
A Abdelkefi ◽  
MR Hajj
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Wind Turbine Blades

Fracture Characterization of Adhesive Joints in Carbon/Epoxy Wind Turbine Blades

2012 ◽  
Author(s):  
Yi Hua ◽  
Linxia Gu
Keyword(s):  
Shear Modulus ◽  
Wind Turbine ◽  
Adhesive Joint ◽  
Turbine Blades ◽  
Adhesive Layer ◽  
Adhesive Joints ◽  
Wind Turbine Blades ◽  
Fracture Characterization ◽  
Initiation And Propagation

The objective of this work is to predict the fracture behavior of adhesive joints in the 4-ply carbon/epoxy wind turbine blades through finite element method. The influence of through-thickness flaw in the adhesive layer was examined. The contour integral method was used for evaluating the stress intensity factors (SIF) at the flaw tips, while the strength of the joint was assessed through the crack initiation and propagation simulation. The effect of adhesive shear modulus has also been investigated. Results suggested that the maximum stress occurred at the adhesive-shell interface and increased stress levels were observed in the case of adhesive layer with flaw. It also highlighted distinct edge effects along the thickness of the adhesive joint. Compared to the perfect adhesive, the static strength of the adhesive joint with flaw remained unchanged. Large shear modulus of the adhesive diminished the strength of the adhesive joint with the increased SIF.

Refined Delamination Factor Failure Characterization of Composite Wind Turbine Blade

2011 ◽  
Vol 21 (8) ◽  
pp. 1227-1244 ◽  
Author(s):  
V. A. Nagarajan ◽  
S. Sundaram ◽  
K. Thyagarajan ◽  
J. Selwin Rajadurai ◽  
T. P. D. Rajan
Keyword(s):  
Wind Turbine ◽  
Composite Laminates ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Reinforced Composite ◽  
Delamination Factor ◽  
Glass Fiber Reinforced ◽  
Useful Power ◽  
Composite Blades

Wind turbines are used to convert the kinetic energy of wind into useful power. The wind turbine blades are fabricated using glass fiber-reinforced composite materials. Wind turbine blades are complex section. In order to improve the strength of the blades under varying loading conditions, spars are embedded in it. The spars are fastened with the composite shells of the blades using bolted connections. In order to affect this fastening, holes of appropriate size were drilled in the composite laminates. Delamination is the major failure in composite blades which is induced during drilling. Delamination is quantitatively measured using digital means. A comparison between the conventional ( FD) and adjusted ( FDA) delamination factors is presented. In order to effectively quantify the delamination, refined delamination factor ( FDR) is proposed. It is found that the proposed FDR predicts the failure in a better manner when compared with predictive capabilities of FD as well as FDA.

scholarly journals Characterization and Mechanical Testing of Manufacturing Defects Common to Composite Wind Turbine Blades

2017 ◽  
Author(s):  
Jared W. Nelson ◽  
Trey W. Riddle ◽  
Douglas S. Cairns
Keyword(s):  
Wind Turbine ◽  
Mechanical Testing ◽  
Mechanical Response ◽  
Turbine Blades ◽  
Analysis Data ◽  
State University ◽  
Wind Turbine Blades ◽  
Manufacturing Defects ◽  
Montana State University ◽  
Damage Models

Abstract. The Montana State University Composites Group performed a study to ascertain the effects of defects that often result from the manufacture of composite wind turbine blades. The first step in this multi-year study was to systematically quantify and database these defects before embedding similar defects into manufactured coupons. Through the Blade Reliability Collaborative, it was determined that the key defects to investigate were fiber waves and porosity. An inspection of failed commercial-scale wind turbine blades yielded metrics that utilize specific parameters to physically characterize a defect. Methods to easily and consistently discretize, measure, and assess these defects based on the identified parameters were established to allow for statistical analysis. Data relating flaw parameters to frequencies of occurrence were analyzed and found to fit within standard distributions. Additionally, mechanical testing of coupons with flaws based on this physical characterization data was performed to understand effects of these defects. Representative blade materials and manufacturing methods were utilized and both material properties and damage progression were measured. It was observed that flaw parameters directly affected the mechanical response. While the data gathered in this first step is widely useful, it was also intended for use as a foundation for the rest of the study; to perform probabilistic analysis and comparative analysis of progressive damage models.

scholarly journals CHARACTERIZATION OF WAVINESS IN WIND TURBINE BLADES USING AIR COUPLED ULTRASONICS

2011 ◽  
Author(s):  
Sunil Kishore Chakrapani ◽  
Vinay Dayal ◽  
David K. Hsu ◽  
Daniel J. Barnard ◽  
Andrew Gross ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Air Coupled Ultrasonics
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