EXPERIMENTAL STUDY OF LOOSENING OF THREADED FASTENERS DUE TO DYNAMIC SHEAR LOADS

This paper presents a study on loosening of threaded fasteners subjected to dynamic shear loads. A fundamental analysis of loosening reveals that a fastener can loosen at lower loads than previously expected due to localized slip at the contact surfaces. Four different loosening processes of a screw under different conditions of slip at the head and thread contact regions are identified. Experimental results illustrating these loosening processes are presented. In addition, the minimum dynamic shear force required to initiate loosening is determined experimentally.