Expansion joints cannot be inserted on an element that is either already rigid or an expansion joint. Bends, however, can be at either end of the element where you are inserting the expansion.
You do not have to give a length on the element where you are inserting the expansion joint.
The six types of expansion joint models supported currently by CAESAR II are:
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Untied single bellows
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Tied single bellows
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Hinged single bellows
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Gimbaled single bellows
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Untied universal bellows
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Tied universal bellows
The four possible joint end types are:
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Welded-end
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Slip-on flange
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Weld neck flange
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Plate flange
If the length of the element to receive the expansion joint model is given, then the expansion joint assembly should fit within this length. If it does not, a warning message displays. If a universal joint has been requested, the length of the receiving element should be at least long enough to accept the smallest possible universal length, as defined by the minimum spool piece size from the manufacturers' database. If the element to receive the universal expansion joint model is zero, you are prompted for the expansion joint length. If the element to receive the universal expansion joint model had an original length, then the maximum possible space available for the universal is reported and you are asked for the length. If the element to receive any expansion joint is longer than the expansion joint to be inserted, you are prompted for the end of the element where the joint should be inserted. Overall universal lengths should be limited to about 10 times the pipe diameter before the center spool piece weight begins to become a problem.
If there is a bend at either the From or the To end of the element to receive the expansion joint, then you must define the length of the element.
To find extra nodes needed for the expansion joint model, CAESAR II starts with the element From node and increments by one until enough nodes not used elsewhere in the model are encountered. It is these nodes that are reported in the Proposed-model dialog box.
Angular stiffnesses reported are given in the current set of units. Only the translational stiffness label is found at the top of the bellows stiffness report. If you are unsure about the rotational stiffness units, they may be seen either in the help screens or in the UNITS report from the LIST option.
You are prompted to adjust the stiffness for the expansion joint if the highest operating temperature is given and not equal to the expansion joint catalog design temperature. This reduces bellows stiffnesses greater than those published in the catalog.
Bellows, tie-bar, and hinge/gimbal assembly weights are combined and distributed over the expansion joint rigid end pieces.
The expansion joint modeler makes every attempt possible to generate nodes in the model that are unique. Inspect the nodes that are generated closely and make sure that you do not use them unintentionally in any future model building.
Review the generated CAESAR II models and be sure that everything is consistent with your intentions.