Numerical simulation of mono- and bi-adhesive aluminium lap joints

摘要

In single-lap bonded joints the stresses are maximum at the edges,where failure usually begins,while in the centre stresses are the lowest.Stress concentration towards the ends of a bonded lap joint depends,to some extent,on the relative stiffness of the adherend and the adhesive used.For a given adherend,the lower the stiffness of the adhesive used in the bondline,the lower the stress concentration,giving rise to potentially higher joint strength.This paper discusses the failure mechanism of bi-adhesive joints,where a flexible adhesive is used at the joint edges,while a less ductile adhesive is used in the centre of the overlap.The results show an increase in shear strength of the bi-adhesive-bonded joints compared with those in which single adhesives were used over the full length of the bondline.The increase of the apparent lap-shear strength was qualitatively predicted,through finite element modelling.