Strength of Spot Welded Joint Pairs as Determined by Layout

Tests were made to compare the performance of spot-weld pairs in lap-shear tests. Lap-shear coupons were made in mild steel and aluminum with pairs of welds aligned along and perpendicular to the loading direction. These results were compared to single spot weld samples.

It was found that the pairs of welds did not double the strength of the joint compared to a single spot weld. Welds perpendicular to the loading direction only increased the peak load by 64% in steel and 85% in aluminum. Weld alignment along the loading direction increased steel joint strength by only 38%, but 100% in aluminum.