Jacket End Cap
Use a jacket end cap to rigidly connect all six degrees of freedom of the coincident nodes of a jacketed pipe (i.e., the node on the core pipe and the corresponding node on the jacket pipe (“J” node) are tied together so that both nodes have the same displacements and rotations).
A “Jacket End Cap” is used at each end of a jacket pipe (which could be made up of several jacket spools) only to connect the jacket pipe to the core pipe, beyond which only the core pipe layout may continue as shown in the figure below.
A jacket end cap is input at a jacketed pipe node by typing “j” in the Data column or selecting “Jacket End Cap” from the Data Types dialog.
You will need this to secure the jacket pipe to the core pipe rigidly. Sometimes (depending on the combination of restraints), you may get a “Stiffness Matrix not positive definite” error, which may be corrected by inserting a jacket end cap.