Custom Expansion Joint

Custom expansion joints model any combination of linear and rotational restraints at pipe connection nodes. Rigid restraints are replaced with elastic restraints having specified flexibility to allow movement in desired directions.

By default, custom expansion joints feature six rigid restraints (three linear and three rotational). Remove selected restraints and replace them with elastic restraints of specified flexibility.

Custom expansion joints support up to three linear and three rotational restraints. Available restraint types:

Rigid double-acting - Restricts movement in both directions along its axis (default for all six restraints)
Spring - Elastic restraint requiring flexibility input

To create a custom expansion joint:

Select the node
Choose Insert > Expansion Joint > Custom EJ or click the toolbar icon

The properties dialog appears (Fig. 1).

Fig. 1. Custom expansion joint restraint properties. Linear Y-axis and rotational X-axis restraints are free, replaced with elastic springs of specified flexibility.

Property	Description
Name	Element name. Displays in 3D view when checked.
Thrust area	Input thrust area to account for pressure thrust force. Required only for expansion joints with elastic axial restraints. Not used in analysis for other cases.
Restraint type	Two restraint types available: rigid and elastic. Direction automatically calculated for rigid restraints.
Local axes	When unchecked, coordinates are global (X,Y,Z). When checked, coordinates are local (Xm,Ym,Zm). All restraints must be mutually perpendicular. Select "other" to specify custom restraint direction. Restraint direction defined by three angles between restraint vector and global coordinate axes. Minutes expressed as tenths of degrees (up to two digits). Example: 30.25 indicates 30°15'. Positive angles require no "+" sign. More...
Restraint direction	Direction restricting mutual displacement or rotation of pipe ends.
Flexibility	Flexibility of elastic restraint.

For detailed restraint information, see "custom expansion joint restraints" and "custom restraints".

View expansion joint analysis results in the Expansion Joint Deformation Table.

Menu and Toolbar Access

To insert a custom expansion joint, select the desired node and use: Insert > Expansion Joint > Custom EJ

or click the toolbar icon.

To view custom expansion joint properties:

Double-click it in the 3D view
Select it and click the toolbar icon