Local Failure - ASME SEC VIII-Div 2-Part 5 for fillet weld

[Ray6]

Hi Folks,
I am performing FEA analysis to investigate a fillet weld. My question is mostly regarding local failure (both elastic and elastic-plastic) as well as fatigue assessment (elastic method) based on ASME SEC VIII-Div 2-Part 5.
There is no machining on the weld, so weld toes are "Toe as-welded".
If I model the weld toe with sharp edge and no fillet radius it will create singularities. Is it any typical fillet radius to be used in FEA for fillet welds toes as they welded? Especially for checking local failure.

Thanks,

 

[r6155]

I don't trust FEA calculations when used by people with no manufacturing and inspection experience. In general, the calculators are in offices away from problems during manufacturing. The best practice in this case is to round the fillets and the calculations that do not represent reality do not work.
I apologize but it is my experience over many years (including nuclear).

Regards

 

[DriveMeNuts]

Fatigue assessment is a dark art. There are no precise answers.
The fatigue penalty factor applied to the smooth bar method in ASME VIII Div 2 is based on WRC Bulletin 432 (See Div 2 Table 5.12). You will find explanations of many approximations and loopholes in this bulletin, including for sharp corners. I think it recommends linearising singularities and applying a large FSRF.
Playing around with applying a fillet radius may allow you to avoid linearising (although this is not in accordance with the code rules). It's a dark art.