Expansion Joint Deformation

This table displays linear and rotational expansion joint deformation as projections on coordinate axes. Linear deformation is mutual pipe end displacement, while rotational deformation is mutual rotation of pipe ends. Deformation sign depends on the direction of local axes of elements adjoining the expansion joint.

For universal expansion joints the relative displacements of flexible joint (deformations) are checked using the following summary equation:

If allowable torsion rotation available, then 4th member is added to the equation above

For axial expansion joint the summary calculated as equivalent axial deformation x divided by allowable axial deformation xa:

Lb – Corrugated length of bellows

Lu – Distance between outermost ends of convolutions

Dm – Mean diameter of bellows convolutions

For single use compensators, deformation values for the welding moment are displayed (at welding temperature input in  Project Settings).

Table view and contents depend on two properties, which must be input:



Operating Mode

Choose operation mode for which the results will be displayed

Maximum - the maximum value will be displayed in every cell from all operation modes

Here you can see analysis results from each of additional force-based loading, seismic, wind, and ice loading

Design state selection

For every operating mode software calculates several submodes (piping states)

For more information, see force and effect combination.

Occasional Loads

  • Maximim + Seismic. Seismic load cases are considered

  • Maximum and minimum + Seismic


Linear and rotational expansion joint deformation is displayed as projections on coordinate axes:

  • Local Axis (Design/Allowable) (Xm, Ym, Zm) - in local expansion joint coordinate system with calculation of design axial, shear, angular bending and angular torsion deformation. The values are compared to allowable ones

  • Global Axis (X, Y, Z) - ΔX, ΔY, ΔZ, φX, φY, φZ (fig. 1.a)

  • Local Axis (Xm, Ym, Zm) - in local element coordinate system ΔXm, ΔYm, ΔZm, φXm, φYm, φZm (fig. 1.b)

Fig. 1. Expansion joint deformation in global (general) and local coordinate systems


Note Description

Expansion joint skew exceeds allowed

Expansion joint skew conditions not met . More...

Deformation exceeds axial expansion

Condition not met. Actual equivalent axial deformation exceeds allowable axial expansion Δk. Piping model or expansion joint properties must be changed. More...

Deformation exceeds rotational expansion

Actual rotational deformation exceeds allowable rotational expansion. Piping model or expansion joint properties must be changed.

Deformation exceeds lateral expansion

Actual lateral deformation exceeds allowable lateral expansion. Piping model or expansion joint properties must be changed.

Menu Access

After analysis: Output > Expansion Joint Deformations