International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4491-4499 © Research India Publications. http://www.ripublication.com

Modeling and analysis of wind turbine blade with advanced materials by simulation Vedulla Manoj Kumar Department of Mechanical Engineering, PG Scholar, VFSTR University, Guntur-522213, AP, India B Nageswara Rao Department of Mechanical Engineering, Associate Professor, VFSTR University, Guntur-522213, AP, India Sk. Farooq Department of Mechanical Engineering, Assistant Professor, VFSTR University, Guntur-522213, AP, India Email:farooq. 314@gmail. com Correspondence author Abstract Wind turbine efficiency depends up on one of the important parameters as the speed of the blade. for a lighter blade a small wind force is enough to rotate it, where as a heavy blade will require large and steady wind loads. To improve the wind turbine performance the blade material is being changed from epoxy glass to epoxy carbon. The modeling was done in Pro-E and the static and dynamic structural analysis is carried out by using ANSYS software. The blade was subjected to FEA studies to demonstrate its ability to withstand the extreme loading conditions as defined in the international offshore wind standard. The results confirmed the design to have acceptable performance with regard to total deformation, directional deformation, Equivalent stresses, Normal stresses and Shear stresses. We found better results for epoxy carbon material compared with epoxy glass that is discussed in this paper. Keywords Wind turbine, epoxy glass, epoxy carbon, Pro-E, ANSYS

NOMENCLATURE Symbol R S HAWT CL CD

Description Rotor Swept area Horizontal Axis Wind Turbine Coefficient of lift Coefficient of Drag

INTRODUCTION Wind energy is one of the fastest growing sources. Various wind turbine concepts have been developed and built to maximize the energy harnessed, to minimize the cost, and to improve the power quality during the last two decades. Today, there are thousands of wind turbines generating electricity and energy to power for our demanding lifestyles. Between the years of 2000-2016, wind power became a rapidly growing concept. Currently, the use of wind power throughout the whole world has more than quadrupled. The United States is

currently the leader of countries in the usage of wind power and the amount of energy being generated through wind power [1, 2]. Compared to many other conventional energy sources, wind power’s environmental effects are fairly minor. Wind power does not release any toxic gas pollution into the atmosphere and does not consume any amount of fuel. The only energy that is used due to wind power is the energy used in actual construction of the wind power plant. One other minor environmental impact of these wind power plants is the danger to airborne animal such as birds. However, the number of birds killed by these wind power plants is less substantial than the animals affected by the air pollution caused by nongreen energy sources [3, 4]. The wind turbines depend on the same aerodynamic forces created by the wings of an aero plane to cause rotation. An anemometer that continuously measures wind speed is part of most wind turbine control systems. When the wind speed is high enough to overcome friction in the wind turbine drive train, the controls allow the rotor to rotate, thus producing a very small amount of power. This cut-in wind speed is usually a gentle breeze of about 4 m/s. Power output increases rapidly as the wind speed rises. When output reaches the maximum power the machinery was designed for, the wind turbine controls govern the output to the rated power. The wind speed at which rated power is reached is called the rated wind speed of the turbine, and is usually a strong wind of about 15 m/s. eventually, if the wind speed increases further, the control system shuts the wind turbine down to prevent damage to the machinery. This cut-out wind speed is usually around 25 m/s[5, 6]. Demand of renewable energy plays an increasingly important role as fossil fuels become more and more expensive and harder to justify in expenses. It is expected that wind energy will contribute 1. 1 trillion kilowatt-hours of the total 3. 3 trillion kilowatt-hours of renewable energy predicted to be supplied by 2030. Furthermore, it is expected that only sun and wind can provide economical alternative energy sources, as other exotic renewable energy sources remain expensive and unproven [7, 8].

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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4491-4499 © Research India Publications. http://www.ripublication.com commercial examples of thermoplastics being used for this engineering application has been found [9, 10, 11, 12].

Figure 1: Schematic Diagram of Wind Energy System

Figure 2: 2 MW Wind Turbines at 40 MW Offshore Wind farm in Denmark

GLASS AND CARBON FIBER COMPOSITES While various materials have been applied successfully in wind turbine blades, fiberglass based Composites predominate. This is mostly because fiberglass is a low-cost and high tensile strength material. It is also easily knitted and woven into desired textiles to meet different engineering requirements. Usually the fiberglass is embedded within a plastic matrix to form a composite known as glass reinforced plastic (GRP). Carbon fiber is also becoming more popular because it has higher modulus, lower density and higher tensile strength than fiberglass and it is less sensitive to fatigue. However, carbon fiber is more expensive than fibreglass and it is difficult to align the fibers to maintain good fatigue performance. Recently, there is increased use of hybrids combining glass and carbon together to achieve moderate mechanical performance with moderate cost. Also fiberglass and carbon/wood hybrids are currently promising materials options for blades. In composite structures, matrix, also called binder, is the resin used to hold fibers in position and make the blade strong. The most common thermo set matrices are unsaturated polyesters, vinyl esters and epoxies Thermoplastics were also developed in the past, however, the performance of these materials, such as PBT and PET, are lower than thermo sets. At present, no

COMPONENTS OF WIND TURBINE BLADE A focus is now being made on the Wind Turbine blade components due to its importance in construction and working under extreme loads. This section briefly discusses the major components of the wind turbine blades. Rotor: Sometimes called the hub, this is used to connect the blades to the gear box and power generation train within the nacelle. Nacelle: an enclosure which contains the electrical and mechanical components, namely the gear box, the brake, the speed and direction monitor, the yaw mechanism and the generator. Gearbox: Many turbines have a gearbox that increases the rotational speed of the shaft to match the required rotation speed of the generator/alternator. Some smaller turbines (under 10 KW) use direct drive generators that do not require a gearbox. Generator: Wind turbines typically have an AC generator (housed in the nacelle) that converts the mechanical energy from the wind turbine’s rotation into electrical energy. Synchronous generators require less rotational speed than asynchronous ones and thus are often operated without gearbox even in bigger wind turbines. Tower: Towers are usually tubular steel structures (about 80 m/260 feet high) which support the rotor and nacelle. It also raises the rotor high in the air where the blades are exposed to stronger winds. They consist of several sections of varying heights. The tower sits on a reinforced concrete foundation, so that it is well fixed onto the ground. Blades: The modern rotor blades are made of composite materials, making them light but durable. Blades are often made of fiberglass, reinforced with polyester or wood epoxy. Vacuum resin infusion is a new material which is gaining popularity among manufacturers. Most wind turbines have three blades. Blades are generally 30 to 50 meters (100 to 165 feet) long, with the most common size around 40 meters (130 feet). Blades typically represent approximately 22% of the value of a wind turbine. Transformer: The electricity generated by wind turbines must be delivered to the electrical grid. In order to do this, the voltage needs to be stepped up for energy transmission. There is usually, at least, one large transformer that is shipped with a wind turbine project and is considered a critical component especially for DSU and operational BI. Wind turbine blades are subjected to external loading, which includes flap wise and edge wise bending loads, gravitational loads, inertia forces, loads due to pitch acceleration, as well as torsional loading. The wind turbine blade requires high strength to withstand the critical conditions, low weight, high stiffness and high fatigue resistance and reliability.

MODELING OF WIND MILL BLADE USING PRO-E Pro-E is a suite of programs that are used in the design, analysis, and manufacturing of a virtually unlimited range of product. In Pro-E we will be dealing only with the major front-

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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4491-4499 © Research India Publications. http://www.ripublication.com end module used for pan and assembly design and model creation, and production of engineering drawings.

Figure 3: Sketcher of wind turbine blade

Epoxy Glass Analysis From the analysis we got the total deformation of epoxy glass at maximum case is 955. 33 mm and the minimum is o mm. The equivalent stress under static structural analysis maximum is 10. 822 mm and minimum is 0. 036363 mm and from the figure the max equivalent stress occurs near the centre and minimum stress took place at edge of the blade. From the figures 5. 4 section we observed that directional deformation in X axis at maximum position is 954. 76 mm and minimum position is 0 mm and the directional deformation at Y axis in maximum case 0. 78247 mm and minimum case-33. 5 mm and finally on the directional deformation at Z axis maximum is 13. 655 mm and minimum is-8. 2239 mm. From the figures in this section we got the deformations about x and y axis maximum at tip of the blade and minimum at other end and similarly for z axis the maximum deformation and minimum deformations occurred at same location near the left side edge. From the section 6. 5 we analyzed that the normal stresses in X and Z directions at maximum and minimum positions occurred at centre location and for normal stresses in Y direction is produced at right edge of the blade that is shown in figure. The shear stress in the XY, YZ, XZ planes is shown in the 5. 6 section. The shear stress in the XY plane at maximum and minimum is 2. 3605 mm,-1. 9619 mm respectively and the both maximum and minimum shear stress takes place at same location. The shear stress in the ZY plane at maximum and minimum is 0. 86999 mm,-0. 92152 mm respectively and the both maximum and minimum shear stress took place at same location and at the right side edge position. The shear stress in the XZ plane at maximum and minimum is 1. 9788 mm,-1. 1255 mm respectively and the both maximum and minimum shear stress took place at same location.

Figure 4: Model of wind turbine blade

From the figures we have observed that the modeling of wind mill blade using Pro-E software after completion we go over ansys to analyze the design.

ANSYS ANSYS Work bench analysis The ANSYS Work bench platform is the frame work upon the industry’s broadcast and deepest suite of advanced engineering simulation technology is built. An innovative project schematic view ties together the entire simulation process, guiding the user through even complex metaphysics analyses with dragand-drop simplicity. With bi-directional CAD connectivity, powerful highly-automated meshing, a project-level update mechanism, pervasive parameter management and integrated optimization tools, the ANSYS Work bench platform delivers unprecedented productivity, enabling simulation.

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Figure 5. 1: Static structural of epoxy glass

International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4491-4499 © Research India Publications. http://www.ripublication.com

Figure 5. 4. 2: Directional deformation in y-axis

Figure 5. 2: Total deformation of epoxy glass

Figure 5. 3: Equivalent stress of epoxy glass Figure 5. 4. 3: Directional deformation in Z-axis

Figure 5. 5. 1: Normal stress in x-axis

Figure 5. 4. 1: Directional deformation in x-axis

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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4491-4499 © Research India Publications. http://www.ripublication.com

Figure 5. 6. 2: Shear stress in YZ plane Figure 6. 5. 1: Normal stress in y-axis

Figure 5. 6. 3: Shear stress in XZ plane Figure 5. 5. 3: Normal stress in z-axis

Epoxy carbon analysis

Figure 5. 7: Static structural of epoxy carbon

Figure 5. 6. 1: Shear stress in XY plane

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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4491-4499 © Research India Publications. http://www.ripublication.com The static structural body of epoxy carbon shows that the fixed support A and force B in the figure.

Figure 5. 10. 1: Directional deformation in X-axis

Figure 5. 8: Total deformation of epoxy carbon

The total deformation of epoxy carbon maximum case is 729. 9 mm and minimum is 0 mm and this deformation plays a key role to design the any structure. For a good and safe design we always need less deformation otherwise it shows the effect on the structure.

Figure 5. 10. 2: Directional deformation in Y-axis

Figure 5. 9: Equivalent stress of epoxy carbon

The Equivalent stress of epoxy carbon maximum case is 10. 514 mm and minimum is 0. 036428 mm and this von misses stress or equivalent stress plays a vital role to design the any kind of structure.

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Figure 5. 10. 3: Directional deformation in Z-axis

International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4491-4499 © Research India Publications. http://www.ripublication.com From the figures 5. 10 section we observed that directional deformation in X axis at maximum position is 729. 46 mm and minimum position is 0 mm and the directional deformation at Y axis in maximum case 0. 56259 mm and minimum case-25. 469 mm and the directional deformation at Z axis maximum is 10. 426 mm and minimum is-6. 3219 mm. From the figures in this section we got the deformations about x and y axis maximum at tip of the blade and minimum at other end and similarly for z axis the maximum deformation and minimum deformations occurred at same point near the left side edge.

Fig 5. 11. 3: Normal stress in Z-axis

From the section 5. 11 the normal stress in X axis maximum and minimum stresses are came at same point and the maximum stress is 4. 8557 mm and minimum stress is-4. 6264 mm. The normal stress at maximum and minimum in Y axis is 1. 5349 mm,-1. 9402 mm respectively and the normal stress at maximum and minimum in Z axis is 10. 278 mm,-10. 418 mm respectively. The maximum and minimum stresses took place at almost same location. Figure 5. 11. 1: Normal stress in X-axis

Figure 5. 12. 1: Shear stress in XY plane Figure 5. 11. 2: Normal stress in Y-axis

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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4491-4499 © Research India Publications. http://www.ripublication.com COMPARISON AND RESULT ANALYSIS OF EPOXY GLASS AND EPOXY CARBON OF A WIND TURBINE BLADE Distribution

EPOXY GLASS TOTAL DEFORMATION MAX 955. 33 (mm) MIN 0 EQUVIALENT SHEAR MAX 10. 822 STRESS (Mpa) MIN 0. 036 DIRECTIONAL MAX 954. 76 DEFORMATION IN X-AXIS MIN 0 (mm) DIRECTIONAL MAX 0. 78 DEFORMATION IN Y-AXIS MIN -33. 5 (mm) DIRECTIONAL MAX 13. 655 DEFORMATION IN Z-AXIS MIN -8. 22 (mm) NORMAL STRESS IN X- MAX 4. 807 AXIS (Mpa) MIN -4. 53 NORMAL STRESS IN Y- MAX 1. 74 AXIS (Mpa) MIN -2. 19 NORMAL STRESS IN Z- MAX 10. 67 AXIS (Mpa) MIN -10. 67 SHEAR STRESS IN XY- MAX 2. 36 AXIS (Mpa) MIN -1. 96 SHEAR STRESS IN YZ- MAX 0. 86 AXIS (Mpa) MIN -0. 92 SHEAR STRESS IN XZ- MAX 1. 97 AXIS (Mpa) MIN -1. 12

Figure 5. 12. 2: Shear stress in YZ plane

EPOXY CARBON 729 0 10. 51 0. 035 729. 46 0 0. 56 -25. 46 10. 426 -6. 32 4. 85 -4. 62 1. 53 -1. 94 10. 27 -10. 41 2. 88 -2. 35 1. 12 -1. 10 2. 17 -1. 39

RESULT AND DISCUSSIONS In this paper especially the total deformation and equivalent shear stresses shows best results by using the material epoxy carbon than epoxy glass for Wind turbine blade. By observing the above tabulated values and the analysis finally we conclude that epoxy carbon is better than epoxy glass.

Figure 5. 12. 3: Shear stress in XZ plane

The shear stress in the XY, YZ, XZ planes is shown in the 5. 12 section. The shear stress in the XY, YZ and XZ planes at maximum and minimum position is 2. 8854 mm,-2. 3599 mm; 1. 1213 mm,-. 1028 mm ; 2. 1782 mm,-1. 3923 mm respectively. The both maximum and minimum shear stresses took place at same location for XY and YZ planes and for XZ plane the maximum shear stress took place at the right side edge position and minimum stress occurred at centre of the blade.

CONCLUSIONS In this research paper work, Pro-E software was used for designing and modeling of the horizontal axis Wind turbine blades. The Analysis work is carried out by Ansys workbench software.  The Static Analysis results indicates that, Epoxy Carbon material under goes the minimum deformation of 729 mm as compared to the other material epoxy glass.  The Minimum Von-misses Stress of 0. 035 Mpa was observed in epoxy carbon material as compared to the other material.  From strength and stiffness point of view Epoxy carbon materials performing better than the other material considered in this work.

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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4491-4499 © Research India Publications. http://www.ripublication.com FUTURE SCOPE This methodology can be extended for different materials i. e., smart materials to get more efficiency and better performance in near future.

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