| As an important connectors of wind turbine, the fatigue strength of high strength bolts are directly affect the carrying capacity, securitybehavior and fatigue life of the structure.Tower is the key load bearing member of wind turbine, so it is very important to predict the 20-year-fatigue life of wind turbine tower flange connecting bolts. For the distribution of a larger number of full circle flange bolts, threaded modeling process is complex, the inner bolt stress analysis problems and other issues, the paper from the engineering point of view, research adapted to the wind turbine tower flange fatigue strength of the algorithm coupling bolts, and make comparative analysis by combing the working algorithm and finite element analysis.Comprehensively analyze the current domestic and international research status about fatigue life of wind turbine tower flange connecting bolts, established the relationship between outside load and bolt stress by Schmidt-Neuper model and finite element analysis. And choseconservative engineering algorithm for bolt fatigue life analysis. According to S-N curve of bolt material in GL2010 specification, derived the standardization S-N curve which was fitted in the.nCode fatigue analysis software. Cumulated fatigue damage of the full circle flange bolts by Miner cumulative damage theory and rain flow counting, and then identified and analyzed the fatigue life of the most dangerous parts of the bolts. The results showed that: the maximum damage bolt in?172.8 and ?176.4 position, the fatigue damage value was 0.555 <1, which was met the design requirements.Established the screw connection axisymmetric model for the dangerous part(0.555)of bolt which was the result of engineering algorithm,infer the stress distributioninscrew by the finite element analysis. The results showed that: the farther away from the thread surface of the nut, the less stress.Cumulated the fatigue damage of dangerous bolt according to the result of the finite element analysis, and compared with the result of engineering algorithm: Accumulated fatigue damage was 0.593 by the finite element analysis which was slightly larger than the result of engineering algorithm(0.555). It was more in line with actual working conditions bolts and fatigue life prediction was more reliable.Analyzed the influence of preload, the number of bolts and thickness of flange to th fatigue life of bolt.The research results can provide a technology basis and reference for prediction for the fatigue life of wind turbine tower flange connecting bolts... |
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