On the Directionality of the Strength of Spot Weld

In the tensile shearing test of spot weld the load axis is parallel to the surface of the welded plate, while in the cross tensile test it is perpendicular to the surface. But in the case of the service structure, in which the spot weld is used as a joint of plates in the vehicle, the load axis is in various directions.

In this report, the strength of spot welds is obtained under various load axes with a new test apparatus. The load axis is changed in the range of 20° to 90°. Under these conditions yielding strength and ultimate strength are obtained.

The results are analyzed using a two dimensional photoelastic method.

The conclusions obtained are as follows;

1. 1.
   The maximum strength is not greatly effected by load axis because the sheet is greatly deformed before fracture.
2. 2.
   Yielding strength is clearly effected by load axis. This is shown with a two dimensional photoelastic test.