Edge Joint Efficiency

[jlight]

I am trying to find a reference for the efficiency of an edge joint. All I can find is that they are not very strong. A stress concentration factor for an edge joint would also be helpfull. Thanks

 

[metengr]

jlight;
By design, an edge joint is like a notched weld joint specimen because you have two members along the same plane that are joined on one end - e.g., the tight gap of the two members that are fused in the weld deposit is like a pre-cracked weld joint. Typically, this type of weld joint is used in thin member welding, like sheet metal.

To determine joint efficiency you could weld a coupon simulating your material and wall thickness and send it to a mechanical test lab. By definition, the joint efficiency is the weld strength/strength of the parent metal. The weld coupon could be designed with both members having a 90 degree flat so that the welded edge joint can be pulled apart or separated with grips in a tensile machine.

The mechanical test would be inexpensive and would yield practical results. As far as stress concentration factor, I would use the inverse of the efficiency factor calculated from the tensile test results, unless somone has a better idea.

 

[GRoberts]

I'm not sure how the code addresses efficiency, but it will be a lot more efficient if you can also fillet weld (especially after back gouging to assure CJP if possible) the inside of the joint so that the root of the weld does not have a sharp notch.