Thank you Peter for your guidance.

Unfortunately i still have some question and need your help.

If i'm not mistaken you can merge several shell bodies into one bodies with "mesh merge", is it correct? or you try to explain that "mesh connection" is a "mesh merge"?

Why in your "mesh connection group" you only have 4 mesh connection?
In my model there is more than 20, is it because you already merge it?
For the "Manual contact region", do i need manually setting this to all my shell element edge? because i have 23 shell bodies.

Let me attach to you my last model without any warning, but still there is no "connection" and my "mesh connection" have 21 children.
Is this model "mesh" and "connection" ready to give the correct result (of course need to assign some analysis boundary later) or still need to be revised?

Your guidance and answer will be very appreciated.

Thank you very much Peter.