Michael,
I'm trying to specify the movements of the pipe at those two points in the horizontal pipe because of the expansion. I tried to replicate this arrangement with the help of x, y, z, rx, ry and rz restraints to specify the rotational as well as translation flexibility because of the pipe downward expansion.
I provided lateral "rotational restraints with gap" to provide the rotational motion and [b]only"axial translational restraint with gap"[/b] to specify the telescopic movement, on the first end of the telescopic arrangement (Node 20 as per my sketch). Similarly, I provided only "translational restaints with gap" on the second end of the arrangement (Node 30 as per my sketch) for the axial and vertical downward movement of the node because of exapansion.
Before the Node 20 of the arrangement, there is a +Y restaint on the straight pipe piece, which acts as a pivot (fulcrum) for the telescopic arrangement to function.
I think this explains my arrangement completely.
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Regards
myjin