Ball Joint

Related Topics

This expansion joint allows rotation of two connected pipes around 3 axes.

Pipes rotates around each other if resultant moment M is greater than the friction moment Mf:

The friction moment Mf is calculated automatically by linear or logarithmic interpolation depending on pressure P in each operating mode, between [Mf1, P1], [Mf2, P2], and [Mf3, P3] values.

For example, following graphic is used for ASME type HYSPAN Barco ball joints (logarithmic interpolation between [P1, M1], [P2, M2]):

Expansion joint will not move if resultant moment M will be lower than the friction moment Mf:

All expansion joint properties can be taken from expansion joints database by pressing the "..." button and selecting the appropriate expansion joint.

Expansion Joint analysis results can be found in Expansion Joint Deformation Table.






Element name. If checked then it shown in 3D view

Friction Moment Mf1, Mf2, Mf3

Expansion joint will rotate it torsion moment greater that friction moment, Mf

Pressure P1, P2, P3

The pressure values, corresponding with torque moments Mf1, Mf2, Mf3

Logarithmic scale

If checked, the logarithmic interpolation is used between [Mf1, P1], [Mf2, P2], and [Mf3, P3] values when calculating the Mf for each operating mode

Allowable rotation

Allowable rotation angle - maximum allowable torsion rotational deformation around Ym and Zm axes. Value used for expansion joint deformation analysis. Value must be obtained from manufacturer. Allowable torsion rotation is always 360 degrees.

Menu and Toolbar Access

To insert a ballasting weight, select the desired node and use the menu option: Insert > Expansion Joint > Ball

To view ballasting weight properties: