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.