Wind Turbine Tower Connection Strength Analysis And Experimental Research

Wind energy is a safe, clean, renewable green energy. The use of wind energy has important implications for sustainable economic development because it does not cause pollution and ecological damage to the environment. Under the strong support of the policy, China has made great progress on wind power. The wind power has maintained a fast growth all over the world whether the total installed capacity or the new installed capacity. With the rapid development of wind power, the wind power industry have occurred a lot of wind tower collapse incident in recent years. After analysis of the accident, causing wind turbines cause of the collapse caused by strong winds in addition to excessive load, as well as insufficient strength flange bolts, and improper fastening bolts during installation and other issues. This paper is to analysis and study, tested the tightening of the flange bolts the strength of the wind turbine towers connected systems. The main contents include:(1) Introduced the preload method of controlling a wind turbine tower bolts. The commonly used high strength bolt preload methods are corner tightening method, torque preload method, hydraulic tensioning preload method. The analysis of the advantages and disadvantages of each method is to select the appropriate method of installation for the wind turbine tower.(2) Introduce the basic theory of ultrasonic bolt stress testing technology, using acoustic elasticity theory, deduced the relationship with its own formula for the axial stress elongation of the bolt. Sound elasticity theory and technology provides a method for fastening bolt axial force detection.(3) According to the Xinjiang Wind Farm power of 1.5MW wind turbine tower theory calculations, the forces of the various conditions of wind turbines are analyzed to bolt strength safety check.(4) Detection of bolt pre-tightening force at the scene of the installation. Introduces the Bolt Mike Ⅲultrasonic bolt stress tester using the method and the selection of related parameters and determine, through the actual test data analysis, the data can reflect the fan tower drum flange bolt actual loading situation and has the guidance function for the installation of the fan.(5) Building the finite element model of wind flange bolt connection, analysis the finite element results of flange bolts obtained in storm conditions and make the comparative analysis the theoretical calculations, field measurement and finite element analysis results.Finally, the paper summarizes the results of the intensity analysis of wind tower flange connection system and the control of bolt preload, and prospects of the need for further study of the problem.