Stress Reduction Effect of Tapering Thread Bolts and Nuts Wich Have Slightly Different Pitches

摘要

Previously several methods were proposed to reduce the stress concentration through improving bolts and nuts profile. Among those methods, (1)Tapering thread bolt (CD bolt) were proposed for stress reduction and (2) Special nuts were designed to have slightly different pitches. In this paper, a kind of nut is designed with providing slightly different pitches between the CD bolt and nut, so that the prevailing torque is appearing in order to obtain the anti-loosening and stress reduction effects. It is found that the maximum static stress concentration can be decreased by 28.6 %, and the maximum stress amplitude can be decreased by 23.9 % compared with the cases of standard bolts and nuts.