Investigation of critical stresses of a single lap-jointed cantilevered beam

The stress distribution along the whole single lap-jointed cantilevered beam has been investigated using the 3-D linear elastic finite element method. Specifically, finite element solutions of the stress distributions in the bonded section have been obtained for four typical characteristics of adhesives. The FE analyses results indicated that there are stress gaps existing at the lower interface and the upper interface for the stress components S 11, S 22, S 12 and S 13: the bigger the shore hardness of the adhesive, the smaller the stress gaps. The FE analyses results also indicated that the stress field in the whole single lap-jointed cantilevered beam is dominated by the normal stresses components S 11, S 33 and the shear stress component S 13. The stress component S 11 is the biggest component in the order of magnitude but S 33 is potentially the most dengerous component because it is associated with the peel stress which is the enemy of bonded joints. The numerical results show that the stress ratios are different for different stress components as well as different adhesives. However the stress ratios of the two ends of the bonded section are nearly same.