Hello,
It is an age old question but I'm asking about best practice in representing the weld in a model of a steel fabrication, particularly for use with the fe-safe Verity method.
The fabricated frame has a significant number of fillet welds between rectangular hollow section members. When it comes to fatigue, the devil is in the detail so I need to represent the welds appropriately and consistently. Fillet welds have the pre-existing crack at the joint, of course, where the end face of the RHS is not fused to its neighbour member. Full penetration welds are superior with respect to endurance but this analysis is verifying the life of an economical weldment using fillet welds.
I have a 3D multi-body solid model and I could fuse all of the joints, this would be the easiest workflow but doesn't represent the fillet weld at all. The next obvious technique is to ensure that the 'end face crack' remains and to model all of the fillet welds as triangular extrusions; this is very CAD intensive and avoiding unrealistic sharp weld ends is also challenging.
What are the time efficient and effective techniques to use?
Transforming the geometry to surfaces using mid-plane extraction is attractive in that the weld may then be added as shells forming the hypotenuse of the weld section and the member end faces remain disconnected from the neighbour in the joint (the crack). The mid-plane mesh does create more work in extending all of the joining member end by half section thickness. Extracting the outer member faces avoids this and the shell may cater for this offset from the mid-plate. In a shell mesh weldment model, the weld can even be omitted and the silhouette of the fillet weld formed in the mesh face of the member to define the weld line.
Are there any techniques in solid modelling, with the Verity module, that eliminates extruding solid fillet welds? The representative stiffness in the joint to compromised to some extent without the solid weld section present, but this is also true of the shell mesh without hypotenuse shells. Is it appropriate to consider connecting the solid mesh only at the outer perimeter of the RHS, where it contacts the other member in the joint?
Please forward if you have references/links to interesting examples (SAE weld challenge produced solid model examples?).