Research Of High Strength Bolt Failure Caused By Several Factors

This paper use the existing hardware and software facilities, study the influence factors of fatigue strength on high strength bolt.From the two factors of concern, the influence on the fatigue life consider the preloaded force and thread shape, specific contents are as follows:1) Study the fatigue elementary theory knowledge in thorough, analysis the stress on the bolts and the fatigue life of bolt used estimation method, based on that the bolt fatigue cumulative damage are analyzed.2) By applying different preloaded force on the bolt connection fatigue tests, this paper study the relations of the preloaded force and fatigue life,determine the best preloaded force range under this paper condition.3) Use the ANSYS finite element analysis method to study the test bolt,compare the finite element analysis results with the tests results. Prove the feasibility of the scheme, provide the theory basis for the following bolt finite element analysis.4) Based on ANSYS finite element analysis method to study the bolt thread of contact analysis, get the stress distribution on thread roots and analysis the relationship between stress concentration of thread roots and high strength bolts life, also do some research on the influence of different radius of bolt thread roots for fatigue properties.5) Introduced the tolerance within the scope of the allowance into the finite element analysis model of bolt, analyzes the effect of pitch tolerance on the thread roots stress concentration. Study the influence of the fatigue properties with the same pitch tolerance in different locations to the bolt.