My analysis is a straight line with both ends are hub connectors. There are valves at middle. This is subsea piping inside a skid. One side connect to flexibile pipeline and the other side connect to rigid pipeline. The analysis is limited at hub connectors, external forces and moments are applied at both connectors to account effect of flexible pipeline and rigid pipeline.

The hub connector has a special configuration. It has a hub body will be welded with main piping. And a cover (call as hub support) with two conical pins below for alignment purpose. Hub body and hub support are connected together by a shear key.

Structure steel below has to provide two holes to align with conical pins (not tight fit). The hub connector itself is just resting on steel structure. And the hub body can move and rotate relative with hub support within clearance.

Due to very big Moments apply on the hub connector, I have to consider three factors into analysis:
a. Include maximum clearance between hub body and hub support (in translations and rotations)
b. Include the hub support stiffness
c. Including steel frame configuration

My modeling method:
1. At center line: Define restraints with gap (clearance between hub body and hub support) and stiffness to simulate hub support. No any Cnode
2. There will be a rigid element goes down to connect with steel frame. Define restraints with gap (clearance between structure holes and conical pins) with Cnode

Any comment on this modeling approach?