Taper's angle influence on the structural integrity of single-lap bonded joints

The effect of conventional inside and outside tapers was addressed considering angles of 30°, 45° and 60°. The strain state of the joints was analyzed with an optical technique and an electrical gauge. Parametric studies were performed using the numerical method to investigate the role of taper geometries and taper angles on the stress distributions of adhesive joints. The statistical analysis of the numerical stresses reported within this paper allowed to get conclusions about which of the taper geometries conducted to higher adhesive compression levels. Experimental results showed that the reduction of the angles of taper increases the joint strength for all types of tapers and this was in agreement with the numerical results obtained from finite element analysis. The joints with outside tapers have higher tensile/shear strength than the joints with reverse or normal adhesive tapers. Local and global strains of the joints with the normal adhesive tapers showed different values, especially for the taper angle of 60°. The mid-line of the adhesive layer of the inside and adhesive tapers showed similar average shear-peel load levels, but because the inside taper geometry induces more compression of the adhesive and the position of the peaks of shear and peel stresses is not coincident, the inside tapering showed to be preferable.