Determining Weld Size From FEA VonMises Plot

[Oceania]

Dear All,

I have been asked to develop weld sizes from a Von Mises plot of a rectangular tank c/w stiffeners. The model was created in SOLIDWORKS/COSMOSM and as such I understand this created a solid brick element model from the parametric model.

I read a NAFEMS report based on a FEMNET project relating to the use of plate models and having to extract particular node stresses and use these to determine minimum fillet weld throat size. I understood the issue here being the relationship between the weld toe stress being remote from the reported connecting node stress.

For a brick element model is it possible to use the Von Mises stress plot values at the various connection details by dividing the stress by the smallest member thickness to give a through thickness stress. From here I would suppose I could use an effective weld throat size based on the weld rod material and work out intermittent weld size requirements.

I hope this makes sense as the proposed method appears to be too simple which makes me somewhat sceptical.

Thanks in advance.

 

[crisb]

In general I would say its a reasonable approach, assuming there are no unusual details or eccentricities. You may wish to consider using smoothed stresses and axial/shear stresses normal and parallel to the fillet weld rather than using effective stresses. It would be normal to use the material properties of the parent materal and relevant code when sizing the weld.