At the beginning of the last century, wind power as a kind of commercial development value and development prospects of healthy new energy forms, has been a great degree of development. With the development of beautiful China, the harmonious development of man and nature, the continuous development, development and application of wind resource development technology, the discussion and research on the key components of wind turbine system is more and more.
The fan blade is a fibrous reinforced composite made of thin shell structure. The structure is divided into three parts: the first part is the root, the material is generally metal;Horizontal Shaft Wind Driven Generator the second part is the shell, usually the composite material, usually using the glass fiber reinforced material and the matrix resin compound, a blade by two perfusion molding The third part is the main beam supporting the shell, that is, the reinforcement or reinforcement frame, usually made of glass fiber or carbon fiber reinforced composite material.
Wind turbine blades are one of the components in the generator set, through the rotation of the blade wind energy into mechanical energy, and then drive the generator power generation, and finally the mechanical energy into electrical energy. The root of the blade is the key part of the connection between the blade and the rotor of the wind turbine. The complex load effect of the aerodynamic force,Horizontal Shaft Wind Driven Generator gravity and centrifugal force of the blade during the running process will be transmitted through the root of the generator to the generator hub. It is necessary to have the strength, stiffness and stability to meet the requirements. Therefore, the mechanical performance of the blade joint is decisive for the safe operation of the blade. The role of.
Large-diameter blade between the root and the generator hub is often used between the double-headed threaded rod connection, in the blade root prepreg laying process, pre-processing of the bolt sleeve embedded in the bolt sleeve is a circular cross-section , And the surrounding glass fiber reinforced composite material contact area is small, is not conducive to the blade structure to withstand external load, so the need to fill both sides of the bolt "Gong" shaped pad or rectangular pad.
Bolt sleeve and the surrounding glass fiber reinforced composite material connection parts of the force is complex, is the wind turbine unit components are easy to meet the requirements of the site. With the development of large-scale power generation trend, the leaves are softer and longer, the blade and the generator hub or bearing bolt connection parts to withstand complex alternating load, bad conditions of the connection parts. Statistics show that, due to the blade at the junction of the bolt tightening fracture, the root is pulled out of the leaves caused by the safety and quality of the accident is quite serious. In order to improve the economics, reliability and stability of the operation of Horizontal Shaft Wind Driven Generator, it is important to study the safety, effectiveness and durability of the leaves of the leaves. It has important engineering significance for the healthy operation and service life of the whole unit.
In the form of glass fiber reinforced composite material for the main material of the blade of the wind turbine, the connection construction of the blade and the root is the key problem. Wind turbine blades usually have to bear their own weight, inertial force, and so on to dozens of tons of the role, but also consider the impact of extreme wind load. In order to ensure the strength, stiffness and local stability of the wind turbine blades, the glass fiber reinforced composite blades are usually made in the form of a pneumatic shell wrapped around the main beam, sharing the external load.
The data show that the research on the blades of wind turbine abroad is mainly focused on the numerical analysis of the blade structure design process, such as numerical iterative algorithm: using the known conditions, through the iterative process gradually close to the design goal; most of the research focused on the value The algorithm is improved to improve the accuracy, convergence and fastness of the iterative process. There is not much fruit for the design of blade structure of wind turbine system.
The power generation of the horizontal axis wind turbine is proportional to the square of the length of the blade, while the blade gravity is proportional to the blade length cube. With the increasing capacity of the single plant, the blade is getting longer and longer, the strength, stiffness and stability requirements of the blade structure Increasing the strength and stiffness of the structure increases the strength, stiffness and stability of the structure, which avoids the collision of the blades with the tower under extreme wind loads. The performance of ordinary glass fiber has become the limit, can not meet the performance requirements of large wind turbine blades. Therefore, the current more feasible program is to use higher strength and modulus of glass fiber. Among them, the key issue is the double-headed screw and leaf root connection area of the force performance.
The analysis of bolt connections for double-headed rods and leaf roots for Horizontal Shaft Wind Driven Generator is still relatively small. Under normal circumstances, the strength of the threaded rod mainly includes the static strength and fatigue strength. In order to ensure that the threaded rod connection will not occur under the maximum load static strength damage, nor under the cyclic load fatigue fracture, it must be on the rod connection static strength and fatigue strength check. How to improve fatigue strength is the key issue in threaded rod connections.