scholarly journals Effects of geometric non-linearity on energy release rates in a realistic wind turbine blade cross section

2015 ◽  
Vol 132 ◽  
pp. 1075-1084 ◽  
Author(s):  
M.A. Eder ◽  
R.D. Bitsche ◽  
F. Belloni
Keyword(s):  
Wind Turbine ◽  
Energy Release ◽  
Turbine Blade ◽  
Cross Section ◽  
Wind Turbine Blade ◽  
Release Rates ◽  
Energy Release Rates

The Study of the Aerodynamic Force of Wind Turbine Blade by Using FLUENT and MATLAB

2011 ◽  
Vol 225-226 ◽  
pp. 794-797
Author(s):  
He Huang ◽  
Sheng Jun Wu ◽  
Zhuo Qiu Li ◽  
Jin Fan Fei
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Cross Section ◽  
Large Scale ◽  
Aerodynamic Force ◽  
Wind Turbine Blade ◽  
Wind Pressure ◽  
Solid Model ◽  
Blade Surface ◽  
Analytical Work

In this paper, large scale wind turbine blade has been taken for example and two harmful conditions have been chosen as the study targets. Taking a 25 m long wind turbine blade, its solid model is built in CAE. Then take advantage of Computational Fluid Dynamics software-FLUENT to analyze and simulate wind pressure of blade surface acted by aerodynamic force. By means of the numerical method to make curve fitting to bring wind pressure to bear on each cross section of blade accurately, and import it into ANSYS to do further analytical work. It shows that the work should be the firm foundation for further analysis of the wind turbine blade.

Analysis of Wind Turbine Blade Motion: Linear Formulation Including All Aeroelastic Load Couplings

2012 ◽  
Author(s):  
Fouad Mohammad ◽  
Emmanuel Ayorinde
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Cross Section ◽  
Equations Of Motion ◽  
Wind Turbine Blade ◽  
Lagrange Equations ◽  
Horizontal Axis Wind Turbine ◽  
External Work ◽  
Flow Angle ◽  
Pitch Moment

A wind turbine blade similar to a helicopter rotor blade has the structure of a pretwisted beam of a variable airfoil asymmetrical cross-section. A number of approximate theories have been developed by different researchers to study the dynamic behavior of the blade of a horizontal axis wind turbine. Some researchers include warping, but they do not include the blade’s pretwisting. Others include the axial and torsional loadings and the coupling among these loadings but they ignore the bending loading. The new contribution in this study is the consideration of all the extensional, torsional and flexural loadings with their couplings, variable airfoil cross sections with warping effects, shear deflection, rotary inertia and with or without blade’s pretwist to obtain a more accurate dynamic model. To the best knowledge of the authors the simultaneous inclusion of all these factors has not been done before. The aerodynamic loadings (lift, drag and pitch moment) were calculated at each time step for a 14m blade that has a linear decreasing NACA4415 airfoil cross section utilizing a time dependent set of parameters such as angle of attack, material and air density, wind and blade speed, flow angle, yaw, pitch angles. Assuming that deformation is small, the total strain energy and total kinetic energy and external work due to the aerodynamic loading acting on the blade were calculated and used in the Lagrange equations of motion where we obtained the stiffness, mass and damping matrices of the linear dynamic equations of motion. Then the unknown displacements and rotations u, v and w in the directions of x, y and z axes respectively, the bending rotations θ1, θ2 about the y and z axes respectively and the torsional rotation ϕ about the x axis, were solved using the Newmark implicit iteration scheme.

scholarly journals Prediction of Delamination in Wind Turbine Blade Structural Details

2003 ◽  
Author(s):  
John F. Mandell ◽  
Douglas S. Cairns ◽  
Daniel D. Samborsky ◽  
Robert B. Morehead ◽  
Darrin H. Haugen
Keyword(s):  
Wind Turbine ◽  
Energy Release ◽  
Strain Energy ◽  
Turbine Blades ◽  
Strain Energy Release ◽  
Fatigue Loading ◽  
Release Rates ◽  
Structural Details ◽  
Energy Release Rates ◽  
Strain Energy Release Rates

Delamination between plies is the root cause of many failures of composite materials structures such as wind turbine blades. Design methodologies to prevent such failures have not been widely available for the materials and processes used in blades. This paper presents simplified methodologies for the prediction of delamination under both static and fatigue loading at typical structural details in blades. The methodology is based on fracture mechanics. The critical strain energy release rate, GIC and GIIC, are determined for opening mode (I) and shearing mode (II) delamination cracks; fatigue crack growth in each mode is also characterized. These data can be used directly for matrix selection, and as properties for the prediction of delamination in structural details. The strain energy release rates are then determined for an assumed interlaminar flaw in the structural detail. The flaw is positioned based on finite element analysis (FEA), and the strain energy release rates are calculated using the virtual crack closure feature available in codes like ANSYS. The methodology has been validated for a skin-stiffener intersection. Two prediction methods differing in complexity and data requirements have been explored. Results for both methods show good agreement between predicted and experimental delamination loads under both static and fatigue loading.

scholarly journals Prediction of Delamination in Wind Turbine Blade Structural Details

2003 ◽  
Vol 125 (4) ◽  
pp. 522-530 ◽  
Author(s):  
John F. Mandell ◽  
Douglas S. Cairns ◽  
Daniel D. Samborsky ◽  
Robert B. Morehead ◽  
Darrin J. Haugen
Keyword(s):  
Wind Turbine ◽  
Energy Release ◽  
Strain Energy ◽  
Turbine Blades ◽  
Strain Energy Release ◽  
Fatigue Loading ◽  
Release Rates ◽  
Structural Details ◽  
Energy Release Rates ◽  
Strain Energy Release Rates

Delamination between plies is the root cause of many failures of composite material structures such as wind turbine blades. Design methodologies to prevent such failures have not been widely available for the materials and processes used in blades. This paper presents simplified methodologies for the prediction of delamination in typical structural details in blades under both static and fatigue loading. The methodologies are based on fracture mechanics. The critical strain-energy release rate, GIC and GIIC, are determined for opening mode (I) and shearing mode (II) delamination cracks; fatigue crack growth in each mode is also characterized. These data can be used directly for matrix selection and as properties for the prediction of delamination in structural details. The strain-energy release rates are then determined for an assumed interlaminar flaw in a structural detail. The flaw is positioned based on finite-element analysis (FEA), and the strain-energy release rates are calculated using the virtual crack closure feature available in codes like ANSYS®. The methodologies have been validated for a skin-stiffener intersection. Two prediction methods differing in complexity and data requirements have been explored. Results for both methods show good agreement between predicted and experimental delamination loads under both static and fatigue loading.

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