20 years.
The wind turbine blade is a thin-shell structure made of composite materials. The structure is divided into three parts: root, shell and keel. There are many types, including pointed head, flat head, hook head, pointed head with flaps, etc. The manufacturing process mainly includes male mold, female mold turning, rolling, heating and curing, demolding, surface grinding, spray painting, etc. Design challenges include aerodynamic design of blade shape, strength, fatigue, noise design, and composite material layup design. The technical difficulties mainly include mold positive processing, mold recasting and resin system selection. The blade is a large composite material structure, and more than 90% of its weight is composed of composite materialss. Each generator typically has three blades, and each generator requires up to four tons of composite materials.
Blade maintenance. Cracks on the blade surface will generally appear after 2-3 years of wind turbine operation. Cracks are caused by low temperatures and natural vibrations of the unit. If the crack appears 8-15 meters from the root of the blade, the crack will deepen and lengthen each time the wind turbine vibrates or stops. As the cracks widen, dirt, wind and sand from the air penetrate, causing the cracks to deepen and widen. Cracks seriously threaten the safety of the blades and can cause cracking, while transverse cracks can cause the blades to break. In case of transverse cracks, reinforcement and restoration of the zipper should be used. Reinforcement and restorationThe zipper requires the use of special tie bars to bond and repair the blade to its original plane.
How are wind turbine blades designed?
Stack molding for wind power generation is a technical name. According to relevant public information, wind power overlay molding is a technology that can build wind turbines by converting flat surfaces into three-dimensional structures. It can make wind power equipment more strong, stable and durable, thereby improving its performance and reducing problems such as breakdowns.
Wind turbine blades represent approximately 15 to 20% of the total cost of the wind turbine. At present, the blades of large wind turbines are mainly made of composite materials, and the content of composite materials generally exceeds. 80%. According to statistics, every 6% increase in the size ofThe blades of a wind turbine can increase the amount of wind energy captured by 12%. The original intention of the blade design is to achieve a balance between dynamic efficiency and structural design. The choice of materials and processes determines the actual final thickness and cost of the blade. Structural designers play an important role in how to combine design principles and manufacturing processes, and must find the optimal solution between ensuring performance and reducing costs. Blade force analysis: Pushing on the blade causes the blade to rotate. The distribution of thrust is not uniform but proportional to the length of the blade. The thrust force experienced by the tip of the blade is greater than that of the blade root. Beam design: The bending deformation caused by the self-weight of the blade and external thrust constitutes the main load of the blade. In order to improveTo improve bending performance, unidirectional fiber cloth is used along the length direction of the blade, as well as the upper and lower beams. the caps are connected by a shear web in the middle Separated as much as possible, the shear webs are made of bidirectional fiber fabric and foam (PET) cores laid diagonally to increase overall stiffness. Internal beam structure: In order to reduce production costs, the design canExcept for some unnecessary materials, common blades adopt a hollow design. Foil Wrap: The main function of the foil wrap is to provide an aerodynamic shape. The sandwich structure of the sheet shell increases rigidity. The sandwich structure is composed of a fiberglass surface layer with a foam core material (PET) or a balsa wood core material (BALTEK) in the middle. The sandwich structureis rigid enough to support bending loads while preventing delamination. The fibers distributed diagonally in the housing provide the necessary torsional rigidity. Blade Root Design: The blade root portion is usually designed to be round. At the same time, in order to meet maintenance and other needs, the blade roots are often connected by bolts to facilitate disassembly and assembly. Welded flange connections can be used for metal beams. Geometric size optimization design: Without changing the geometric shape of the blade, the performance of the blade can be changed by adjusting the thickness of the spar cap, and the production cost can be reduced. Thinner blades require thicker spars, which increases production costs. At the same time, the strength of the band must be increased, but as the thickness becomes thinner, theThe total material consumption does not change significantly. In summary, optimal design of geometric dimensions requires careful consideration of many aspects such as fan design, load analysis, structural design and manufacturing cost to achieve the best results.