Flexural behaviour of bonded-bolted butt joints due to bolt looseness

Butt joints containing glued cover plates and bolts are used in structures subjected to severe loading with a view to maximising the structural integrity. The behaviour of such joints is not well understood due to the complex interaction of a large number of components as well as material nonlinearities. This paper presents an analysis of bonded-bolted steel butt joints with particular attention to the effect of the loss of bolt tightness to the structural behaviour. Bonded-bolted butt joints subjected to biaxial stress field have been investigated using three-dimensional finite element modelling subjected to two-step loading, the first involving pre stressing of the bolts followed by application of inplane bending. Effect of looseness of the bolts to the inplane deformation characteristics of the joint has been particularly examined.