On the Anti-Loosening Characteristics of M16 Threaded Fasteners under Vibratory Conditions

摘要

There have been wide applications of threaded fasteners since its inception few centuries back. However, under hostile vibrating condition, threaded fasteners loosen clamping force leading to failure of the system. Many researchers investigated the mechanism of loosening, and found out the factors behind the loosening. With this understanding, many investigators tried to develop threaded fasteners having locking characteristics. In the present work, loosening characteristics of M16 high tension steel bolt (HTS) with conventional nut, nylock nut, hybrid double nut (one conventional nut and one nylock nut), flat washer, spring washer, inside serrated washer and outside serrated washer are tested under accelerated vibrating conditions using an indigenously made test rig for 11000 oscillations. The loss of clamping force from the initial one indicates the extent of loosening. Hybrid double nut using one conventional nut and one nylock nut has been found out to show remarkably good anti-loosening characteristics over the others tested. On the other hand, the nylock nut applied on a conventional bolt shows better anti-loosening ability than the other nuts and washers tested apart from hybrid double nuts.