Bolted joint preload decay and the effect of multiple reuse

Improper design or maintenance of threaded fastener bolted joints can lead to safety issues and/or loss of life due to failure of the joint. This paper describes the effect of multiple uses of threaded fasteners on the associated loss of preload. Experimental test data is used to model the behaviour of fastener usage against preload loss; a predictive capability is derived accounting for fastener diameter changes. Assessment of the behaviour identifies that fastener thread pitch is an important contributor to the decay of preload due to reuse.