Fatigue Analysis of an Innovative Extensible Wind Turbine Blade

2016 ◽  
Author(s):  
Jiale Li ◽  
Xiong (Bill) Yu
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Fatigue Damage ◽  
Wind Turbine Blade ◽  
Time Interval ◽  
Data Set ◽  
Low Wind Speed ◽  
Wind Turbine Tower ◽  
Utility Scale

This paper describes the feasibility analyses of an innovative, extensible ‘smart’ blade technology aims to significantly improve the wind turbine energy production. This innovative ‘smart’ blade will be extended at low wind speed to harvest more wind energy. It will be retracted to its original shape above rated wind speed, to protect the blade from possible damages under high wind speed. The extended blade, however, will inevitably increase the fatigue damage of the wind turbine blade of which fatigue demand, which often controls the design requirement of wind turbine blade. A rain-flow counting method is used for calculating stress range cycles during turbine blade operation. The analyzes model in the research is built based on a 100 kW utility-scale wind turbine installed on the campus of Case Western Reserve University with a data acquisition system installed on the wind turbine tower to monitor the operation data continuously over the years. In this analyses, the data set consists of four years’ wind speed data at 10-minutes time interval and blade rotational speed from March 2014 to February 2015 have been used. The results show that the fatigue damage of this extensible blade increased is acceptable considering its increased power output.

scholarly journals Modal Analysis of Vertical Wind Turbine Blade

2018 ◽  
Vol 217 ◽  
pp. 01003 ◽  
Author(s):  
Lee Zhou Yi ◽  
Choe-Yung Teoh
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Modal Analysis ◽  
Turbine Blade ◽  
Wind Turbine Blade ◽  
Flow Induced Vibration ◽  
Low Wind Speed ◽  
Teak Wood ◽  
Blade Failure ◽  
Wind Induced Vibration

Wind turbines cannot simply be installed in Malaysia due to low wind speed condition. the project has analyzed the existing wind turbine blade (Aeolos-V 1k) design based on modal properties using computational approach (ANSYS Workbench) and redesign it. the modal analysis is simulated to observe natural frequency and corresponding mode shaped of the system under free vibration. the flow induced vibration can cause blade failure due to resonance or fatigue. Fluid Structural Interaction (FSI) ANSYS is used to the determined the interaction between the wind flow and the blade. Harmonic Response ANSYS is used to analyze the frequency response of the blade under wind induced vibration. After modification, the first mode has increased from 91.42 Hz to 102.12, since it is more than 50.92 Hz (Turbine maximum operating frequency), resonance would not occur during operating condition. the Aeolos-V’s blade has been modified by using. teak wood material and. redesign the blade for weight. reduction and aim for lower blade cost. the weight of modified blade has reduced 72.8 % after using teak wood and the efficiency of the wind turbine also increased. Modified design has been tested under Malaysia maximum wind speed of 9.44 m/s, the yield stress of teak wood (10.3 MPa) is higher than the maximum stress (4.2 MPa) obtained under force vibration which gives safety factor of 2.4. Hence, modified blade is reliable, efficient and more economic for Malaysia.

Aerodynamic Comparison of Straight Edge and Swept Edge Wind Turbine Blade

2008 ◽  
Author(s):  
R. S. Amano ◽  
Ryan J. Malloy
Keyword(s):  
Renewable Energy ◽  
Wind Energy ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Low Cost ◽  
Renewable Energy Sources ◽  
Optimization Technique ◽  
Wind Turbine Blade ◽  
Direct Result ◽  
Low Wind Speed

Recently there has been an increase in the demand for the utilization of clean renewable energy sources. This is a direct result of a rise in oil prices and an increased awareness of human induced climate change. Wind energy has been shown to be one of the most promising sources of renewable energy. With current technology, the low cost of wind energy is competitive with more conventional sources of energy such as coal. This however is only true in areas of high wind density. These areas are not as abundant and therefore the number of profitable sites is limited. This paper explores the possibility increasing the number of profitable sites by optimizing wind turbine blade design for low wind speed areas. The two methods of optimization that are investigated are first, optimizing the angle of attack and chord length for a given airfoil cross section at different positions along the blade and second implementing a swept blade profile. The torque generated from a blade using only the first optimization technique is compared to that generated from a blade using both techniques as well as that generated by NTK500/41 turbine using LM19.1 blades. Performance will be investigated using the CFD solver FLUENT.

Control Framework and Integrative Design Method for an Adaptive Wind Turbine Blade

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Hamid Khakpour Nejadkhaki ◽  
John F. Hall
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Design Method ◽  
Design Procedure ◽  
Wind Turbine Blade ◽  
Control Technique ◽  
Angle Distribution ◽  
Control Framework ◽  
Integrative Design

Abstract A control framework and integrative design method for an adaptive wind turbine blade is presented. The blade is adapted by actively transforming the twist angle distribution (TAD) along the blade. This can alleviate fatigue loads and improve wind capture. In this paper, we focus on wind capture. The proposed design concept consists of a rigid spar that is surrounded by a series of flexible blade sections. Each section has two zones of stiffness. The sections are actuated at each end to deform the TAD. A quasi-static control technique is proposed for the TAD. The controller sets the position of the blade actuators that shape the TAD during steady-state operation. A design procedure is used to define the required TAD as a function of the wind speed. This is based on an optimization procedure that minimizes the deviation between the actual TAD and that found in the aerodynamic design. The design inputs for this optimization problem include the stiffness for each zone of the section, and the actuator locations along the blade. Given the optimal TAD at each wind speed, the free position of the blade is established using a dynamic programming technique. The position is selected based on minimal actuation energy according to wind conditions at any installation site. The proposed framework is demonstrated using a National Renewable Energy Laboratory (NREL) certified wind turbine model with recorded wind data. An increase in efficiency of 3.8% with only a deviation of 0.34% from the aerodynamic TAD is observed.

Study of Fatigue Test Loading Spectrum for Wind Turbine Blade

2014 ◽  
Vol 889-890 ◽  
pp. 221-224
Author(s):  
Gao Hua Liao ◽  
Jian Zhong Wu ◽  
Yong Jun Yu
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Fatigue Test ◽  
Turbine Blade ◽  
Time History ◽  
Wind Load ◽  
Wind Turbine Blade ◽  
Fatigue Life Analysis ◽  
Test Loading ◽  
Loading Spectrum

According to the principle of equivalent, the approach to draw up the fatigue test loading spectrum of wind turbine blade is presented. Analysis of wind load characteristics, based on ARMA (Autoregressive Moving Average Model) for the simulation of wind speed, wind load simulation example is given. Using Bladed software, the wind speed-time history is converted to a moment-time history that is the equivalent of blade root.Using data compression technology and the rain flow counting algorithm, load represented by a 2D matrix examples is given.The one-dimensional symmetry loading spectrum draw up, the complexity can be simplified, and provides the necessary foundation for fatigue life analysis.

A Flexible Wind Turbine Blade With an Actively Variable Twist Distribution to Increase Region 2 Efficiency: Design and Control

2017 ◽  
Author(s):  
Hamid Khakpour Nejadkhaki ◽  
John F. Hall
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Wind Turbine Blade ◽  
Design Solution ◽  
Angle Distribution ◽  
Stiffness Ratio ◽  
Aerodynamic Efficiency ◽  
Simulation Results ◽  
And Control

A method for designing and controlling a novel wind turbine blade is presented. The blade is modular, flexible, and additively manufactured. Conventional blades are monolithic and relatively stiff. The conventional method for improving aerodynamic efficiency is through generator torque control. The anisotropic nature of the additive manufacturing (AM) process has the potential to create a flexible blade with a low torsional-to-longitudinal-stiffness ratio. This enables new design and control capabilities that could be applied to the twist angle distribution (TAD). Simulation results suggest this can increase the aerodynamic efficiency during Region 2 operation. The suggested blade design includes a rigid spar with flexible AM segments that form the surrounding shells. The stiffness of each individual segment and the actuator placement define the TAD. In practice, the degree of flexibility for each segment will be established through the design and AM processes. These variations in compliance allow the blade to conform to the desired set of TAD geometries. The proposed design process first determines the TAD that maximizes the aerodynamic efficiency in Region 2. A mechanical design algorithm subsequently locates a series of actuators and defines the stiffness ratio between the blade segments. The procedure is optimized to minimize the amount of variation between the theoretical TAD and that which is obtained in practice. The free-shape TAD is also determined in the final design step. The geometry is chosen to minimize the amount of deflection needed to shape the TAD as it changes with Region 2 wind speed. A control framework is also developed to set the TAD in relation to wind speed. A case study demonstrates the capability of the proposed method. The simulation results suggest that a TAD controlled through five actuators can achieve the full range of required motion. Moreover, the design solution can increase the efficiency at cut-in and rated speeds up to 3.8% and 3.3%, respectively.

Life prediction of wind turbine blades using multi-scale damage model

2021 ◽  
pp. 073168442199588
Author(s):  
Sepideh Aghajani ◽  
Mohammadreza Hemati ◽  
Shams Torabnia
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Fatigue Damage ◽  
Life Prediction ◽  
Turbine Blades ◽  
Damage Model ◽  
Fatigue Loading ◽  
Multiaxial Fatigue ◽  
Wind Turbine Blade ◽  
Wind Turbine Blades

Wind turbine blade life prediction is the most important parameter to estimate the power generation cost. Due to the price and importance of wind blade, many experimental and theoretical methods were developed to estimate damages and blade life. A novel multiaxial fatigue damage model is suggested for the life prediction of a wind turbine blade. Fatigue reduction of fiber and interfiber characteristics are separately treated and simulated in this research. Damage behavior is considered in lamina level and then extended to laminate; hence, this model can be used for multidirectional laminated composites. The procedure of fatigue-induced degradation is implemented in an ABAQUS user material subroutine. By applying the fatigue damage model, life is estimated by the satisfaction of lamina fracture criteria. This model provides a comprehensive idea about how damage happens in wind blades regarding a multi-axis fatigue loading condition.

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