Question

For a butt weld joint of two plates, which one of the following loading scenarios has the least permissible stress?

• A. Tensile
• B. Bending
• C. Bearing
• D. Shear

Hint:

Design welded joints to avoid shear stress across the weld throat. Shear failure is more likely in fillet or butt welds when loaded in-plane.

Answer 1

The Correct Option is D

In butt welded joints, different types of stresses are allowed based on the strength of the weld metal and geometry:
Tensile: Welds can generally handle tensile loads well and permissible stresses are relatively high.
Bending: Permissible stress under bending is lower than tension but still higher than shear.
Bearing: Bearing stress typically refers to compressive stress at contact surfaces and is not usually the limiting factor in butt welds.
Shear: Butt welds are weakest in shear as the shear plane cuts through the throat area of the weld, which is the minimum cross-sectional area.
Hence, the permissible stress under shear loading is the least for butt welds.