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[Ben Müller]

I’m designing a welded tow hook bracket for a lightweight off-road trailer (max gross weight 850 kg), made from 8 mm thick mild steel plates (S355), joined with full-penetration fillet welds. I’m running a static FEA in SolidWorks to simulate pulling and angled side loads during recovery scenarios, but I’m getting unexpectedly low stress values around the weld areas, even with a reasonably refined mesh (avg. element size ~1.5 mm).

Could this be a meshing issue, or is it just an inherent limitation of the way fillet welds are represented in CAD-based FEA? I’m not sure whether I should model the welds explicitly or apply connector-based simplifications.

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[RLess]

Hey, sounds like you’re running into a common FEA issue in SolidWorks. Full-penetration fillet welds often get oversimplified, especially if you’re not modeling the welds directly – which leads to underestimated stresses.
Best fix? Try explicitly modeling the weld bead. It takes a finer mesh but gives much more accurate results. If that’s too much, SolidWorks’ “welded connection” features or mesh refinement tools can help as a compromise. Also, check if you’re using the right material properties — the default base material might not reflect the weld zone properly. A more realistic material model can improve accuracy too.
So yeah, for solid stress results around welds, detailed modeling and mesh tweaks go a long way.

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[Allain Saunders]

Also, it’s worth checking if your material setup takes the weld zone into account. SolidWorks usually just uses the base material, which can miss the mark and underestimate stress. If you can, try assigning a specific material to the welds or just refine the mesh more in that area for better accuracy.

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