Weld Stress in Support Stand 1

[mengnr]

I am trying to calculate the stresses in the welds at the base of a support stand (see attached picture). (The weld is a fillet weld around all sizes of a square cross-section column.) It looks to me like there is no shear stress but only a stress from the bending moment, so there would be no primary shear and the total stress would be Mc/I. Is this right or am I missing something obvious? Thanks.

 

[Ron]

The moment in the column is resolve into a force couple, which produced the shear in the fillet welds.

 

[corus]

The load is equivalent to a direct load at the base plus a bending moment, both of which will give shear.

corus

 

[hokie66]

I think mengr is asking about external shear on the connection, and there is none. But of course, as Ron pointed out, the bending moment has to be resisted by the welds in shear. The vertical load can be resisted either by shear or by direct bearing.

 

[DFLewis]

I agree that there would be no primary shear.

Here's a resource for weld calcs:

http://www.roymech.co.uk/Useful_Tables/Form/Weld_strength.html

For "I" in your stress equation for bending, you would need to determine the second moment of area "I" for throat area of the weld. Otherwise, I think we are on the same page.

Another resource I often use is Mechanical Engineering Design 7th Ed. (Shigley) see chapter 9.

I hope this helps.



DFLewis

http://www.phoenix-engineer.com