Comparative Fatigue Life Assessment of Wind Turbine Blades Operating with Different Regulation Schemes (original) (raw)
Related papers
A simulation model for wind turbine blade fatigue loads
Journal of Wind Engineering and Industrial Aerodynamics, 1999
The paper describes a horizontal axis wind turbine time domain simulation and fatigue estimation program written using the Delphi2+ language. The program models the #apwise motion of a single rotor blade to determine the blade-root fatigue damage of a medium size wind turbine. The e!ects of turbulence intensity, mean wind speed, wind shear, vertical wind component, dynamic stall, stall hysteresis, and blade sti!ness were examined. When all these e!ects were simulated it is found that a reduction in life of about 2 occurs between a low wind speed low turbulence intensity site, compared to a high wind speed high turbulence intensity site.
Numerical and Experimental Analysis of Horizontal-Axis Wind Turbine Blade Fatigue Life
Materials
Horizontal-axis wind turbines are the most popular wind machines in operation today. These turbines employ aerodynamic blades that may be oriented either upward or downward. HAWTs are the most common non-conventional source of energy generation. These turbine blades fail mostly due to fatigue, as a large centrifugal force acts on them at high rotational speeds. This study aims to increase a turbine’s service life by improving the turbine blades’ fatigue life. Predicting the fatigue life and the design of the turbine blade considers the maximum wind speed range. SolidWorks, a CAD program, is used to create a wind turbine blade utilizing NACA profile S814. The wind turbine blade’s fatigue life is calculated using Morrow’s equation. A turbine blade will eventually wear out due to several forces operating on it. Ansys software is used to analyze these stresses using the finite element method. The fatigue study of wind turbine blades is described in this research paper. To increase a tur...
Study of fatigue damage in wind turbine blades
Engineering Failure Analysis, 2009
The inspection of damages detected in some blades of 300 kW wind turbines revealed that the nature of these damages was probably due to a fatigue mechanism. The causes that had originated the failure (superficial cracks, geometric concentrator, abrupt change of thickness) have been studied, verifying, by means of the simplified evaluation procedure of fatigue life of the ''Germanischer Lloyd" (GL) standard, that these causes can explain the failure detected in the period of time in which it happened.
Wind Engineering, 2019
The wind energy has been recognised as one of the rising sustainable energies in the world. The wind turbines are subjected to high aerodynamic loads and they cause vibrations due to the wake formation. The magnitude of the applied loads has significant effects on the crack propagation. The fatigue loads have been identified as one of the key sources of damage, with delamination as the main cause for the failure of the turbine blades. The article presents a review of fatigue damages that have been experienced in the wind turbine blades, and factors that are influenced due to the fatigue loads are discussed. The causes and effects of the fatigue loads have been highlighted, and the ways for preventing the fatigue damage by improving the design lifetime are mainly concentrated in review. The overall review gives an idea for determining and reducing the crack growth in wind turbine blades.
Vibrational Fatigue Analysis of NACA 63215 Small Horizontal Axis Wind Turbine blade
Materials Today: Proceedings, 2018
Wind turbines are critical in structural behaviour, which are characteristically using the wind in order to produce power. In wind machines, blades are considered to be an important component because of its critical profile at different sections, weight, and the structural parameters with relatively high amplitude and high frequency. Life-cycle estimation of wind turbines is crucial to develop their design and maintenance process, since they should have more lifespan with minimum foreign object disruptions as well as low probabilities of failures. Wind turbine is eco friendly technology; it should provide a high lifespan of its whole set up by reduces the major failure factors. Due to the effect of aerodynamic loads acts in the wind turbine blades may cause to fail at unpredictably high an amount, which creates the wind turbine to make fatigue analysis as important factors in its performance. Fatigue life and its analysis of each rotating component is one of the major factors of concern due to the terrible failures that can result from it. In this paper, the fatigue behaviour of wind turbine blade in response to different frequencies has established to the level that the prediction of working lifespan is fitting an essential part of the design process also compare the suitability of a wind turbine blade with different composite materials such as Kevlar, Glass Fiber Reinforced Plastic (GFRP) and Carbon Fiber Reinforced Plastic (CFRP) by simulates the displacement and principal stress using numerical method. The reference component of this paper is modeled by using CATIA. A numerical model of the blade was created using ANSYS Workbench 16.2 in order to estimate the typical mode shapes occurring within the blade based on a wind profile and mass approximating the location where these blades are expected to vibrate. Also, fatigue life of wind turbine blade analyzed for three composite materials and the results are compared in order to find out the optimum material body.
Fatigue Testing of the Small Wind Turbine Blade
International Journal of Mechanical Engineering and Robotics Research, 2022
Blades are the elements of a wind turbine which are the most vulnerable to destruction. Facing the unstable wind (one that changes its speed and direction), they are subjected to cyclic and fluctuating loads. This problem is particularly pronounced in case of small wind turbine (SWT) blades or blades for wind tunnel tests in scale, which are oftentimes made of anisotropic materials or manufactured in a way leading to anisotropy, like 3D-printing. SWT blades have to be designed in a way which will allow them to operate for a long time without any fracture. Hence, the fatigue strength is a key parameter, which determines their operation time and should be tested before putting a wind turbine into operation. The aim of this paper is to describe the methodology of fatigue tests of the small wind turbine blades. Next, the construction of the fatigue test stand and results of the experiment will be examined.
Reliability Analysis of Wind Turbine Blades for Fatigue Life under Wind Load Uncertainty
12th AIAA Aviation Technology, Integration, and Operations (ATIO) Conference and 14th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference, 2012
Conventional wind turbine blades have been designed using fatigue life predictions based on a fixed wind load distribution that does not fully capture uncertainty of the wind load. This could result in early fatigue failure of blades and eventually increase the maintenance cost of wind turbines. To produce reliable as well as economical wind turbine blades, this paper studies reliability-based design optimization (RBDO) of a wind turbine blade using a novel wind load uncertainty model. In the wind load uncertainty model, annual wind load variation has been extended over a large spatiotemporal range using 249 groups of wind data. The probability of fatigue failure during 20-year service life is estimated using the uncertainty model in the RBDO process and is reduced to meet a desired target probability of failure. Meanwhile, the cost of composite materials used in the blade is minimized by optimizing the composite laminate thicknesses of the blade. In order to obtain the RBDO optimum design efficiently, deterministic design optimization (DDO) of a 5-MW wind turbine blade is first carried out using the mean wind load obtained from the uncertainty model. At the DDO optimum design, fatigue hotspots for RBDO are identified among the laminate section points. For efficient sampling-based RBDO process to handle dynamic wind load uncertainty, instead of generating surrogate models of the overall output performance measure, which is 20-year fatigue life, a number of surrogate models of the 10-minute fatigue damages D10 at the hotspots are accurately created using the dynamic Kriging (DKG) method. Using these surrogate models and the wind load uncertainty model, probability of failure of 20-year fatigue life at these hotspots and their design sensitivities are calculated at given design points. Using the sampling-based method, RBDO of the 5-MW wind turbine blade is carried out starting at the DDO optimum design to meet the target probability of failure of 2.275%.
FATIGUE LIFE OPTIMIZATION OF WIND TURBINE BLADE
Wind Turbine is one of the most useful non-conventional energy sources in today's energy crisis scenario. But the initial cost of the Wind Turbine plant is very high. The manufacturing cost of the Wind Turbine blade is about 15-20% of the Wind Turbine plant cost. So it is likely to reduce the investment cost of the Wind Turbine blade by maximizing the service life of the Wind Turbine blades. Different types of loads acting on the Wind Turbine blade and consequential stresses developed in blade are studied. The Finite Element model of Wind Turbine blade is analyzed by using ANSYS software. Fatigue stresses are developed on the Wind Turbine blade due to change in wind speed. The maximum wind speed range (from cut-in to cut-out wind speed) is considered for design of blade as well as predicting the fatigue life of the blade. Morrow's equation is used for calculating the fatigue life of wind turbine blade. The parameters which govern the fatigue life of the blade are the chord length; blade length and the twist angle. For optimizing the fatigue life of the Wing Turbine blade, the length of blade, the chord length and the twist angle, these parameters are varied. Constrained Gradient (Steepest ascent method) method is used for fatigue life optimization of the blade. The twist angle is very sensitive to the fatigue life of the blade than the chord length and the blade length. The fatigue life increases exponentially with the increase in twist angle, while there is parabolic relation between the fatigue life of the blade and the chord length. The fatigue life decreases with increase in the blade length linearly. Due to increase in fatigue life of the blade, the cost of the wind turbine plant gets reduced with more reliability.
Dynamic behavior of wind turbines. An on-board evaluation technique to monitor fatigue
Procedia Structural Integrity, 2018
During their operation, modern aircraft engine components are subjected to increasingly demanding operating conditions, especially the high pressure turbine (HPT) blades. Such conditions cause these parts to undergo different types of time-dependent degradation, one of which is creep. A model using the finite element method (FEM) was developed, in order to be able to predict the creep behaviour of HPT blades. Flight data records (FDR) for a specific aircraft, provided by a commercial aviation company, were used to obtain thermal and mechanical data for three different flight cycles. In order to create the 3D model needed for the FEM analysis, a HPT blade scrap was scanned, and its chemical composition and material properties were obtained. The data that was gathered was fed into the FEM model and different simulations were run, first with a simplified 3D rectangular block shape, in order to better establish the model, and then with the real 3D mesh obtained from the blade scrap. The overall expected behaviour in terms of displacement was observed, in particular at the trailing edge of the blade. Therefore such a model can be useful in the goal of predicting turbine blade life, given a set of FDR data.