Effect of Clearance on Bolt Loosening Behaviors of Segmented Nuts in Pyroshock-Reduced Separation Nut

초록

Pyrotechnic separation nut using the segmented nuts is a kind of low-shock PMDs. While fastening the bolt, the release ring prevents the segmented nuts from spreading out to the radial direc-tion. One of the main causes of bolt loosening is transverse vibration. Thus, the behavior of the bolted joint using the segmented nuts under transverse vibration should be examined. During the manufactur-ing process, a clearance is usually introduced between the outer diameter of the segmented nuts and the inner diameter of the release ring. The clearance may affect bolt loosening under transverse vibration. Therefore, finite element bolt loosening analyses with the clearance of 0.0 mm and 0.1 mm are per-formed to investigate the effect of the clearance. The analyses are carried out referring to Junker vibra-tion test which is the most popular method to measure bolt loosening under transverse vibration. From the results, it is found out that a larger clearance tends to increase the risk of accidental bolt loosening behavior.