I've used Interface, Weld and Fasteners for a model and done a Static analysis. Let me know if anything is Wrong in it.
You set up the interface between the component free and I think is not.
If the components are "welded" or bonded together, you must model the components using bonded interfaces.
Recommended also by the PTC help support. See below
You can try with contact interference also...
You already have an interference between the bottom vertical part (vertical part of the "T" shape assembly) because you don't have any welds in that area. See the picture.
Also, from the experience if you don't go after the welds (to see if the are the right size), I will go without simulate them and bonded surface between the parts will account for the welds.
If you really want to go with the welds please see the below video. It's not mine but I think this is very close to what you trying to do and the most important think is closer to the reality.
Have a great day!
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