Structural Analysis of Wind-Turbine Blades by a Generalized Timoshenko Beam Model

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Alejandro D. Otero ◽  
Fernando L. Ponta
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
3D Structure ◽  
Computational Cost ◽  
Full Scale ◽  
Beam Model ◽  
Wind Turbine Blades ◽  
Operational Conditions ◽  
Variational Asymptotic ◽  
Complex Features

An important aspect in wind-turbine technology nowadays is to reduce the uncertainties related to blade dynamics by the improvement of the quality of numerical simulations of the fluid-structure interaction process. A fundamental step in that direction is the implementation of structural models capable of capturing the complex features of innovative prototype blades, so that they can be tested at realistic full-scale conditions with a reasonable computational cost. To this end, we developed a code based on a modified implementation of the variational-asymptotic beam sectional (VABS) technique proposed by Hodges et al. VABS has the capacity of reducing the geometrical complexity of the blade section into a stiffness matrix for an equivalent beam, allowing accurate modeling of the 3D structure of the blade as a 1D finite-element problem. In this paper, we report some recent results we have obtained by applying our code to full-scale composite laminate wind-turbine blades, analyzing the fundamental vibrational modes and the stress load in normal operational conditions.

Analysis of the Aeroelastic Dynamics of Wind-Turbine Blades

2012 ◽  
Author(s):  
Lucas I. Lago ◽  
Fernando L. Ponta ◽  
Alejandro D. Otero
Keyword(s):  
Wind Turbine ◽  
Strain Energy ◽  
Structural Model ◽  
Numerical Models ◽  
Turbine Blades ◽  
Computational Cost ◽  
Full Scale ◽  
Wind Turbine Blades ◽  
Time Step ◽  
Aerodynamic Model

Reducing the uncertainties related to blade dynamics by the improvement of the quality of numerical simulations of the fluid structure interaction process is a key for a breakthrough in windturbine technology. A fundamental step in that direction is the implementation of aeroelastic models capable of capturing the complex features of innovative prototype blades, so they can be tested at realistic full-scale conditions with a reasonable computational cost. We make use of a code based on a combination of two advanced numerical models implemented in a parallel HPC supercomputer platform: First, a model of the structural response of heterogeneous composite blades, based on a variation of the dimensional reduction technique proposed by Hodges and Yu. This technique has the capacity of reducing the geometrical complexity of the blade section into a stiffness matrix for an equivalent beam. The reduced 1-D strain energy is equivalent to the actual 3-D strain energy in an asymptotic sense, allowing accurate modeling of the blade structure as a1-D finite-element problem. This substantially reduces the computational effort required to model the structural dynamics at each time step. Second, a novel aerodynamic model based on an advanced implementation of the BEM (Blade Element Momentum) Theory; where all velocities and forces are re-projected through orthogonal matrices into the instantaneous deformed configuration to fully include the effects of large displacements and rotation of the airfoil sections into the computation of aerodynamic forces. This allows the aerodynamic model to take into account the effects of the complex flexo-torsional deformation that can be captured by the more sophisticated structural model mentioned above. In this presentation, we report some recent results we have obtained applying our code to full-scale composite laminate wind-turbine blades, analyzing the fundamental vibrational modes and the stress load in normal operational conditions.

scholarly journals Full-scale fatigue tests of CX-100 wind turbine blades. Part II: analysis

2012 ◽  
Author(s):  
Stuart G. Taylor ◽  
Hyomi Jeong ◽  
Jae Kyeong Jang ◽  
Gyuhae Park ◽  
Kevin M. Farinholt ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Fatigue Tests ◽  
Full Scale ◽  
Wind Turbine Blades

scholarly journals PSO-BP Neural Network-Based Strain Prediction of Wind Turbine Blades

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1889 ◽  
Author(s):  
Xin Liu ◽  
Zheng Liu ◽  
Zhongwei Liang ◽  
Shun-Peng Zhu ◽  
José A. F. O. Correia ◽  
...  
Keyword(s):  
Neural Network ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Full Scale ◽  
Wind Turbine Blade ◽  
Blade Design ◽  
Wind Turbine Blades ◽  
Static Testing ◽  
Bpnn Model

The full-scale static testing of wind turbine blades is an effective means to verify the accuracy and rationality of the blade design, and it is an indispensable part in the blade certification process. In the full-scale static experiments, the strain of the wind turbine blade is related to the applied loads, loading positions, stiffness, deflection, and other factors. At present, researches focus on the analysis of blade failure causes, blade load-bearing capacity, and parameter measurement methods in addition to the correlation analysis between the strain and the applied loads primarily. However, they neglect the loading positions and blade displacements. The correlation among the strain and applied loads, loading positions, displacements, etc. is nonlinear; besides that, the number of design variables is numerous, and thus the calculation and prediction of the blade strain are quite complicated and difficult using traditional numerical methods. Moreover, in full-scale static testing, the number of measuring points and strain gauges are limited, so the test data have insufficient significance to the calibration of the blade design. This paper has performed a study on the new strain prediction method by introducing intelligent algorithms. Back propagation neural network (BPNN) improved by Particle Swarm Optimization (PSO) has significant advantages in dealing with non-linear fitting and multi-input parameters. Models based on BPNN improved by PSO (PSO-BPNN) have better robustness and accuracy. Based on the advantages of the neural network in dealing with complex problems, a strain-predictive PSO-BPNN model for full-scale static experiment of a certain wind turbine blade was established. In addition, the strain values for the unmeasured points were predicted. The accuracy of the PSO-BPNN prediction model was verified by comparing with the BPNN model and the simulation test. Both the applicability and usability of strain-predictive neural network models were verified by comparing the prediction results with simulation outcomes. The comparison results show that PSO-BPNN can be utilized to predict the strain of unmeasured points of wind turbine blades during static testing, and this provides more data for characteristic structural parameters calculation.

scholarly journals GA-BP Neural Network-Based Strain Prediction in Full-Scale Static Testing of Wind Turbine Blades

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1026 ◽  
Author(s):  
Zheng Liu ◽  
Xin Liu ◽  
Kan Wang ◽  
Zhongwei Liang ◽  
José A.F.O. Correia ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Back Propagation ◽  
Health Assessment ◽  
Prediction Method ◽  
Full Scale ◽  
Wind Turbine Blades ◽  
Static Test ◽  
Static Testing ◽  
Input Variables

This paper proposes a strain prediction method for wind turbine blades using genetic algorithm back propagation neural networks (GA-BPNNs) with applied loads, loading positions, and displacement as inputs, and the study can be used to provide more data for the wind turbine blades’ health assessment and life prediction. Among all parameters to be tested in full-scale static testing of wind turbine blades, strain is very important. The correlation between the blade strain and the applied loads, loading position, displacement, etc., is non-linear, and the number of input variables is too much, thus the calculation and prediction of the blade strain are very complex and difficult. Moreover, the number of measuring points on the blade is limited, so the full-scale blade static test cannot usually provide enough data and information for the improvement of the blade design. As a result of these concerns, this paper studies strain prediction methods for full-scale blade static testing by introducing GA-BPNN. The accuracy and usability of the GA-BPNN prediction model was verified by the comparison with BPNN model and the FEA results. The results show that BPNN can be effectively used to predict the strain of unmeasured points of wind turbine blades.

A review of full-scale structural testing of wind turbine blades

2014 ◽  
Vol 33 ◽  
pp. 177-187 ◽  
Author(s):  
H.F. Zhou ◽  
H.Y. Dou ◽  
L.Z. Qin ◽  
Y. Chen ◽  
Y.Q. Ni ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Full Scale ◽  
Structural Testing ◽  
Wind Turbine Blades

scholarly journals Aerodynamic Characteristics of a Single Airfoil for Vertical Axis Wind Turbine Blades and Performance Prediction of Wind Turbines

Fluids ◽  
2021 ◽  
Vol 6 (7) ◽  
pp. 257
Author(s):  
Samuel Mitchell ◽  
Iheanyichukwu Ogbonna ◽  
Konstantin Volkov
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Turbine Blades ◽  
Computational Cost ◽  
Aerodynamic Characteristics ◽  
Wind Turbine Blades ◽  
Aerodynamic Forces ◽  
Rans Model ◽  
Wide Range ◽  
Lift And Drag

The design of wind turbines requires a deep insight into their complex aerodynamics, such as dynamic stall of a single airfoil and flow vortices. The calculation of the aerodynamic forces on the wind turbine blade at different angles of attack (AOAs) is a fundamental task in the design of the blades. The accurate and efficient calculation of aerodynamic forces (lift and drag) and the prediction of stall of an airfoil are challenging tasks. Computational fluid dynamics (CFD) is able to provide a better understanding of complex flows induced by the rotation of wind turbine blades. A numerical simulation is carried out to determine the aerodynamic characteristics of a single airfoil in a wide range of conditions. Reynolds-averaged Navier–Stokes (RANS) equations and large-eddy simulation (LES) results of flow over a single NACA0012 airfoil are presented in a wide range of AOAs from low lift through stall. Due to the symmetrical nature of airfoils, and also to reduce computational cost, the RANS simulation is performed in the 2D domain. However, the 3D domain is used for the LES calculations with periodical boundary conditions in the spanwise direction. The results obtained are verified and validated against experimental and computational data from previous works. The comparisons of LES and RANS results demonstrate that the RANS model considerably overpredicts the lift and drag of the airfoil at post-stall AOAs because the RANS model is not able to reproduce vorticity diffusion and the formation of the vortex. LES calculations offer good agreement with the experimental measurements.

scholarly journals Forgószárnyas repülőgép rotorok aeroelasztikus viselkedésének vizsgálata szélturbina lapátok számára kifejelsztett eszközökkel

2019 ◽  
Vol 31 (2) ◽  
pp. 115-126
Author(s):  
Balázs Gáti ◽  
Tamás Gausz
Keyword(s):  
Wind Turbine ◽  
Software Package ◽  
Rotor Blade ◽  
Numerical Solutions ◽  
Turbine Blades ◽  
Rotor Blades ◽  
Wind Turbine Blades ◽  
Operational Conditions ◽  
Rotary Wing ◽  
Multiple Analysis

Rotor blades of an autorotating helicopter or a gyrocopter work very similar to the rotor blades of a wind turbine in skew wind. In this publication we present the result of multiple analysis of a rotor blade of a rotary-wing airplane, but the analyses were performed with a software package developed for investigation of wind turbine blades. The results of several analyses seem to be valid for rotary-wing airplanes in some special, but very important cases, and can be useful for more detailed investigation. It was stated, that the fact leads to uninterpretable numerical solutions, that the angle between the undisturbed airflow and the Tip Path Plane is much lower in case of helicopters and gyrocopters than by wind turbines in most operational conditions .

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