Weld Tearing with Force Perpendicular to Weld

[simon2452]

Gents,

Another one for any keen structural guys.

I know the Yield Stress of the material and have a stress factor in mind.

To go about calculating the maximum shear/tearing force at a distance away from the weld, can i work out the moment by saying:

Force x distance from weld = Moment

Then use in a standard tearing formula ?

Cheers
Simon

 

[kingnero]

Can a non-structural guy give his opinion as well?

What do you mean by standard tearing formula?

The weld will see both the given force (or half of it, if the part is symmetrical) and a moment.
You will have to add and subtract both in function of the location along the weld. This will give you the max stress, at the top of the weld.

Take special precautions at the start and stop of the weld, avoid any stress risers...

 

[simon2452]

Kingnero i did not mean to discriminate of course your opinion is welcome

Formulas such as

https://www.engineersedge.com/weld/weld_stress_formulas_table_chart_9866.htm

My experience lies more in Valves, Regulators, Hydraulics and Gas Flows coming from a Diving/Down-hole Background, However would like to expand my knowledge to the more structural aspects of Mechanical Engineering. The last time i did any bending/moment calculations was in my university degree a long time ago and never with anything involving welds or loading cases similar to the attached.

For most problems i have found Machinery's Handbook / Shigley's etc usefull, however for this particular load case i cannot find an example to use. I presume that with enough backround in bending moments that this would not be considered very complicated.

 

[Engdoitbetter]

As far as I know, in this case your weld is loaded by an axial force plus a bending moment (aka axial eccentric loading).

The distance you need for moment calculation is the distance between the loading point and the center of mass of the weld section (13" + half of the length of the weld), since in theory the bending stress formula is obtained with the hypothesis that the section is bending around a central axis of inertia.

In practice, the stress will be the result of an uniform tensile stress due to axial loading and a linear stress due to bending, which results in a maximum tensile stress at the above edge of the weld.

 

[desertfox]

Hi

I tend to use this site for weld stress calls.

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

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein