FEA of weldments

Famous_Mortimer

What is the best way to model welds when looking at joining plates at a right angle?  Is it best to use bonded contact where the weld touches the metal? New to Mecway.  Love it so far.

Victor

It depends on your goal.

If you want to find the stress in or right next to the weld, ideally model the plates and the bead itself using solid elements in a single mesh. You can also use bonded contact to join the weld bead onto the plates but it may need more mesh refinement to get accuracy right at the interface.

If you just want them to transfer loads between plates, then bonded contact between the edges and faces of shell elements is an easy way. Merging the nodes is alright too but sometimes the meshes won't match up, making that impractical. In both cases, stress right at the joint will be inaccurate using shell elements since they use the plane stress assumption and there's no weld bead in the model.

Andrea

I don't know because you need to model a weld. Take into account that you coul find a severe stress concentration. For weld verification against fatigue load using FE model see IIW recommendations. There is specified how to model the welds using two methods: Hot spot stress or notch stress. As per this method the weldment must be modelled without contact and one could use 3D elements or shell elements. Another reference is DNV-RP-C-203 used on off shore structures.
P.S. these methods are convalidated by many thousands of tests

cirasj

I am interested in what method has worked for this issue.
I too am looking into modeling welds that are attach lifting lugs to a part.