![](../icons_C2/common/areference.gif) |
Pivots are hinge
(conical join)
restraints applied to handle points of virtual parts,
which result in constraining the point to rotate around a given axis. They can be
viewed as particular cases of general hinge joins,
which allow a relative rotation between two points (in the Pivot case, one of the two points is
fixed, along with the pivot axis).
Pivot objects belong to Restraint objects sets.
![](images/aaImageRestraintPivots.gif)
means that there is no translation degree of freedom left in that direction.
means
that there is no rotation degree of freedom left in the direction.
For the fixed point, the program automatically picks the handle of the
virtual part. The user defines the pivot direction, and as a result the
virtual part as a whole is allowed to rotate around an axis parallel to
the pivot direction and passing through the fixed point.
Make sure you fixed all the
global degrees of freedom of your assembly, otherwise a global singularity
will be detected at the time of the Static Computation (such a model is
unsolvable). To allow you to easily correct the model (Static Analysis
Cases only), the singular displacement of the assembly will be simulated
and visualized after computation.
When connected to deformable bodies, the virtual part will
transmit the effect of the Pivot restraint collectively to the entire
connected geometry.
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Pivots can be applied to the following types of Supports:
![](../icons_C2/common/iconblck.gif)
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This task shows how to create a
Pivot on a virtual part.
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You can use the sample15.CATAnalysis
document from the samples directory for this task: a Finite Element Model containing a
Static or Frequency Analysis Case and created a Virtual
part.
Before You Begin:
Go to View -> Render Style -> Customize View and make
sure the Shading, Outlines and Materials options are active in the Custom View Modes
dialog box.
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1. Click the Pivot icon .
The Pivot dialog box is displayed.
![](images/aaPanelRestraintPivot.gif)
2. You can change the identifier of the
Pivot by editing the Name field, if needed.
The Axis System Type combo box allows you to choose between
Global and User-defined Axis
systems for entering components of the pivot axis.
![](_themes/v5r5/ul1.gif) | Global: if you select the Global Axis system, the components of the
pivot direction will be interpreted as relative to the fixed global
rectangular coordinate system. |
![](_themes/v5r5/ul1.gif) | User-defined: if you select a User-defined Axis system, the
components of the pivot direction will be interpreted as relative to the
specified rectangular coordinate system. |
To select a User-defined Axis system, you must activate an existing
Axis by clicking
it in the features tree. Its name will then be
automatically displayed in the Current Axis field.
3. Set the Axis system.
4. In the X, Y,
Z fields, enter the values corresponding to the components of the
pivot direction relative to the selected Axis system.
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![](../icons_C2/common/amethod.gif) |
![](_themes/v5r5/ul1.gif) | You can define the pivot direction by using the compass. The values in the
X, Y, Z fields
correspond to the direction components of the compass principal axis. |
![](_themes/v5r5/ul1.gif) | You can modify the compass orientation either
with the mouse or by editing the compass. |
![](_themes/v5r5/ul1.gif) | By applying the compass to any part geometry, you
can align the
compass directions with the implicit axis directions of that geometry:
drag the compass by
handling the red square and drop it on the appropriate surface. The normal direction to this surface defines the new
direction. Then, click on the Compass Direction
button to take this new direction into account. You can now invert the direction if
desired, by editing the values of the three components. |
5. Select a virtual part.
A symbol representing the pivot direction is displayed on the virtual
part.
6. Modify the pivot direction orientation.
The visualized Pivot symbol orientation is
automatically updated to reflect the
modifications of the compass principal direction.
7. Click OK to create the
Pivot.
A Pivot object appears in the features tree under the active Restraints
objects set.
![](images/6treerestraintpiv.gif)
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![ainfo.gif (980 bytes)](../icons_C2/common/ainfo.gif) |
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![ainfo.gif (980 bytes)](../icons_C2/common/awarning.gif) |
Make sure the computation is finished before
starting any of the following operations. |
![../../../ICONS/icons.doc/src/common/awarning.gif (1007 bytes)](../icons_C2/common/tips.gif)
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Products
Available in
Analysis Workbench
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