Approach 1. Weld material is not added to the model, welds are simulated as weld lines inside and outside the tube. The stress concentration at the ends of weld lines is reasonable, the value can be high because theoretical value is infinite

Approach 2. Weld material is added to the model as a solid ring using Inventor’s Weld feature Weld ring The ring is attached to the left tube and deeply penetrates into the right tube One can see the ring faces sticking out the inner surface of the tube

Approach 2. Connections in Simsolid To see the connections between parts of assembly we use Review Part Connection function on RMB menu on a part Connection between left tube and the weld ring Connection between left tube and the right tube All connections of the left tube NOTE: there is no connection between the weld ring and the right tube. The ring deeply penetrates the right tube and the connections were not found The load path goes through the tubes The weld ring is not stressed much because it is aside of the load path

Approach 3 and 4. Weld material is added to the model as solid insertions of two types Weld insertion Weld insertion, type 1 Weld insertion, type 2 Connections: areal connections between the insertion and tubes, line-type connections between tubes

Approach 3 and 4. Weld material is added to the model as solid insertions of two types Local stress results are better for the blended weld insertions