Weld stress calculation

[Navid.Nik]

I have a handrail post which is connected via a welded plate. I wonder if I am calculating the weld stress correctly. Could someone please correct me if I am wrong? The load and dimensions are shown in the picture. The post is a SHS section.

 

[dik]

I'm not familiar with the formula... you have a Mf = Ff*(l1+l2/2) and this is resisted by lw * Vw *l2 (Vw is the unit capacity of the weld) and you have to resist the horizontal component due to the force itself and this is included in the force from the moment. You calculate the forces on the bolts by simple statics... you also should include for prying action... likely, for small loads, your plate will be approx 12mm (1/2") thick. Also, the moment on your handrail will be increased by the increased length l1 and often normal handrail sizes get 'bumped' up by a size or two.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[desertfox]

Hi Navid.Nik

I can see that the first formula is the bending moment on the weld based at the centre of the bracket but then what you appear to be saying is that the stress due to bending and the shear stress are equal and I believe that is not the case have a look at this site it might help

https://roymech.org/Useful_Tables/Form/Weld_strength.html

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

 

[Tmoose]

SHS = square hollow section .

I think the load path and thus the actual stresses along the weld, the SHS wall, and the welded plate are likely to be shockingly variable.

https://assets-us-01.kc-usercontent...4125-ab8e-f5623a9eb959/RHS7.2.png?w=800&h=600

depending on your actual loading this might be a real big deal.

https://weldtalk.hobartwelders.com/forum/equipment-talk/general-welding-questions/50248-i-get-a-call