Page 138 - Handbook of Adhesives and Sealants

Joint Design 107

Figure 3.10 Lap joint designs.

As shown in Fig. 3.11, tapering or beveling the edges of the joint
greatly improves the load bearing capacity, because it permits those
regions to bend and, thus, to distribute the stress down the length of
the bonded area to some degree. Comparison of curve 1 for untapered
and curve 2 for tapered lap shear joints reveals how much better the
load is shared along the linear axis of the adhesive bond. Figure 3.12
shows the strength advantage that can be gained by tapering the ends
of the standard lap shear specimen.

3.5.1.3 Strap joints. Strap joints keep the operating loads aligned and
are generally used where overlap joints are impractical because of
adherend thickness. Strap joint designs are shown in Fig. 3.13. Like
the lap joint, the single strap is subjected to cleavage stress under
bending forces. The double strap joint is more desirable when bending
stresses are encountered. The beveled double strap and recessed dou-