Failure Of Welds
Failure of welds of various types may be classified based on the types of welds.
1. Butt weld
If the butt welds are reinforced properly, it is unlikely for the failure to obtain in the weld. The fracture normally occurs at some distance from the connection. However if the weld is ground flush with the surface of the plate, the position of the fracture depends on the relative strength of plate and weld. If the tensile strength and yield point of the weld metal are higher than that of the elements, the failure takes place away from the weld. Failure in the weld junction is unusual. Welds stiffened with reinforcements will hinder the failure of the joint under bending. If there is a wide difference in the properties of the materials on joint and member, the failure may occur at the junction.
2. End fillet weld
The plane of failure in the case of a normal convex weld is along the diagonal from the root of the weld. The position of the plane of failure depends on the relative magnitude of tensile and shear stresses. If the fillet weld is having unequal legs, the plane of failure will be nearer to the leg having smaller length. The failure of end fillet welds occurs abruptly with very small deformations.
3. Side fillet weld
In a side convex weld subjected to shear stress along the weld, failure occurs down the throat of the weld. Failure is initiated at the toe of the weld and progress with rotation of the plane associated with considerable deformations. Failure of the plates before the final failure is also usual.