超音波探傷法によるボルトの疲労破壊予知

概要

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It is difficult to perfectly predict the fatigue strength of a bolt in joints at the stage of strength design, since many factors influence the load on the bolt. This study treats the possibility of preventing the fatigue fracture of a bolt by detecting the fatigue crack at the thread root at an early stage by means of the ultrasonic flaw detector. A method is discussed in which the crack is initiated at the bolt thread root near the top surface of the nut in the mating threads by shortening the bolt pitch slightly against the nut pitch. By using this method, it is hoped to lengthen the period from the detection of the crack to the fracture. From the results of fatigue tests, it is clarified that the pitch modification is effective in the case of 0.6% pitch difference and of relatively low mean stress.
社団法人日本機械学会の論文
1986-09-25