,so the results that I am seeing in the last picture that you shared for the FIXED JOINT case is also for when there is no gap between the faces of the two bodies? Or you still kept the distance of 1 mm between the two bodies for the FIXED JOINT case? I actually understood this that the gap of 1 mm is causing some artifacts for both, FIXED JOINT and BONDED (MPC) cases, but if I remove this gap and make the opposing faces of the two bodies to overlap each other, so the fixed joint would also give me the same results as I see for the BONDED (MPC) and Shared Topology, or not?
Secondly, you mentioned this:
Both of these are artifacts from the spider of elements jumping a 1 mm gap, which is not ideal.
Yes, it is not ideal since we are removing 1 mm length in between the two bodies which are being connected, but why is it causing an artifact (in stresses) is something which I would love to understand, because I don't know the reason for these artifacts to arise because of this gap.
You also said this:
reduce the Pinball radius to 0.001 mm, we get a node-to-node spider of MPC connection elements as shown below. This is ideal.
So increasing the pinball radius, to, say, 1.5 mm is not going to be ideal, even when we don't have any gaps between the faces which are being bonded together? Why is node-to-node ideal but node-to-several nodes not ideal?