Flare weld vs. fillet weld question?

[RobertEIT]

I have a question regarding stress in a weld(based on AISC-13th).

Say a D=2 weld size by 1"length fillet weld exerted a 2kips load, the stress in weld will be:

f=2kips/[2*(1/16")(sqrt(2)/2)*1"]=22.627 ksi

but if the weld is a flare weld, the stress in the weld will be:

f=2kips/[2*(1/16")*1"]=16 ksi

i.e., with same weld size, the stress in flare weld will be 1.414 times smaller than fillet weld. Is above statement correct?

Thanks a lot?

 

[Lion06]

Yes, the difference is that the LEG size for the fillet is not the throat size. You actually find the throat for the partial pen weld. I would typically not work in ksi, I typically work in k/in. I take the the effective throat of the partial pen weld and multiply it by 1.4 to get an equivalent fillet weld (1.293k/in/16th, 0.928k/in/16th for old ASD). Then compare that to the actual.

 

[Lion06]

I guess I should say that the reason I always use k/in is that when you treat welds as lines to section properties for torsion or welds subjected to moments, J is in in^3 (not in^4) and S is in in^2 (not in^3). You can calc out the properties pretty easily, but Blodgett several shapes in section 7.4. This is a good section to read just for general knowledge as well.

 

[RobertEIT]

Thanks StructuralEIT!