Bushings

Use the Bushings tool to create bushings and edit their connectivity, properties, and orientation rules.

Create Bushings Using the Bushings Tool

  1. From the Model Browser, select the system to which the bushing is to be added.
  2. From the Model ribbon, click the Bushings icon.
    A guide bar for entity creation appears.
  3. Optional: Select the Pair check box to create a pair entity.
    A bushing entity, like most of the entities that are created in MotionView, can be a single entity or a pair entity. Pair entities help to create models that are symmetric about the Z-X plane of the model. Their properties can also be symmetric about the Z-X plane (in other words, the Y property is mirrored). Asymmetry or symmetry of the bushing can be decided or specified when editing the created bushing.
  4. Select the first body reference (Body 1).
    • Select a body in the modeling window.

      OR

    • On the guide bar, click the Advanced Selector and make your selection in the Model Tree.
    Note: When defining a pair bushing, use pair entities for Body, Origin, and so on.
  5. Select the second body reference (Body 2).
    • Select a body in the modeling window.

      OR

    • On the guide bar, click the Advanced Selector and make your selection in the Model Tree.
  6. Select an origin reference (Origin).
    • Select a point in the modeling window.

      OR

    • On the guide bar, click the Advanced Selector and make your selection in the Model Tree.
  7. Optional: Click to reset the entity selections and select new entities.
  8. Once the reference selections are made, create the bushing using one of the following methods:
    • Click on the guide bar. Next, use the microdialog to edit/orient the bushing.

      OR

    • Click the button that appears at the mouse location in the modeling window. Next, use the microdialog to edit/orient the bushing.

      OR

    • Click to create the entity and exit the selections for this bushing.
    Note: If the selected bushing is a pair entity, use the microdialog to distinguish between the Left and Right and then edit its properties.
    Once the bushing has been added to the model, the corresponding bushing will automatically be displayed in the browser area.
    Note: By default, variables names of entities in MotionView follow a certain convention. For example, all bushing entities have a variable name starting with 'bsh_'. This is the recommended convention to follow when building models in MotionView since it has many advantages in model editing and model manipulation.
Tip: A new bushing can be created from the Model Browser by right-clicking on the Model label (or any system/analysis of your choice) and selecting Add > Force Entity > Bushing or by right-clicking Bushings and selecting Add Bushing.

Edit Bushings

  1. Edit the connectivity using the Bushings tool:
    The bodies, origin, and orientation of a bushing can be edited using the Bushings tool.
    1. Select the Bushing to be edited from the modeling window or the Model Browser.
    2. Click on the Bushings tool icon in the Model ribbon.

      A guide bar for the entity appears along with a micro-dialog for orientation.

    3. Activate the Body or Point collectors in the guide bar that need editing.
    4. Pick a different body or point either from the modeling window or the Advanced Selector .
    To edit the orientation, click on the Orient Marker icon in the microdialog to bring up the Orientation tool.
  2. Edit the properties using the Entity Editor:
    All properties of the Bushing can be edited from the Entity Editor.
    1. Select the Bushing to be edited from the modeling window or the Model Browser. The Bushings Entity Editor is automatically displayed.

    The Entity Editor displays the following properties that can be edited:

    Property Description
    General
    Label Descriptive label for the entity.
    Varname Variable name of the entity.
    ID Integer identifier.
    Active Active state of the entity (True or False). Entity is deactivated if False.
    Body 1 First body the bushing connects to.
    Body 2 Second body the bushing connects to.
    Origin Point of origin of the bushing.
    Properties
    Trans Stiffness/Rot Stiffness Trans stiffness lists force representation due to stiffness along translation directions X, Y, and Z. Rot Stiffness lists torque representation due to stiffness about rotational directions X, Y, and Z.
    (X, Y, Z) Type Select the type of force representation due to stiffness.
    Linear Indicates a linear stiffness value for the bushing along the given direction.
    Value (kx/ktx, ky/kty, kz/ktz) A real value (or a reference data member of type real value).
    Curve Indicates force due to stiffness is represented using a curve (Force/Torque v/s Deflection).
    Curve (kx/ktx, ky/kty, kz/ktz) Select a 2D cartesian or parametric curve.
    Interpolation Interpolation scheme to be used for the curve – AKIMA, CUBIC, LINEAR or QUINTIC.
    Independent variable Solver expression to consider as the independent variable for the curve. Expression defaults to the DM datamember that returns the displacement of the bushing along the given direction (DX/DY/DZ/AX/AY/AZ).
    Spline3D Indicates force due to stiffness is represented using a 3D spline (Force/Torque v/s displacement and another independent variable).
    Spline3D (kx/ktx, ky/kty, kz/ktz) Select a Spline3D entity.
    Interpolation Interpolation scheme to be used for the curve – AKIMA, CUBIC, LINEAR or QUINTIC.
    Independent variable X Solver expression to consider as the first independent variable (X) for the Spline3D. Expression defaults to the datamember that returns the displacement of the bushing along the given direction (DX/DY/DZ/AX/AY/AZ).
    Independent variable Z Solver expression to consider as the second independent variable (Z) for the Spline3D.
    Expression Indicates stiffness force input using a solver expression.
    Expression (kx/ktx, ky/kty, kz/ktz) Solver expression that describes the force along the given bushing direction.
    Trans Damping/Rot Damping Trans Damping lists force representation due to damping along translation directions X, Y, and Z. Rot Damping lists torque representation due to stiffness about rotational directions X, Y and Z.
    (X, Y, Z) Type Select the type of force representation due to damping.
    Linear Indicates a linear damping for the bushing along the given direction.
    Value (cx/ctx, cy/cty, cz/ctz) A real value (or a reference data member of type real value).
    Curve Indicates force/torque due to damping is represented using a curve (Force/Torque v/s Deflection).
    Curve (cx/ctx, cy/cty, cz/ctz) Select a 2D cartesian or parametric curve.
    Interpolation Interpolation scheme to be used for the curve – AKIMA, CUBIC, LINEAR or QUINTIC.
    Independent variable Solver expression to consider as the independent variable for the curve. Expression defaults to the datamember that returns the velocity of the bushing along or about the given direction (VX/VY/VZ/WX/WY/WZ).
    Spline3D Indicates force/torque due to damping is represented using a 3D spline (Force/Torque v/s displacement and another independent variable).
    Spline3D (cx/ctx, cy/cty, cz/ctz) Select a Spline3D entity.
    Interpolation Interpolation scheme to be used for the curve – AKIMA, CUBIC, LINEAR or QUINTIC.
    Independent variable X Solver expression to consider as the first independent variable (X) for the Spline3D. Expression defaults to the datamember that returns the displacement of the bushing along the given direction (VX/VY/VZ/WX/WY/WZ).
    Independent variable Z Solver expression to consider as the second independent variable (Z) for the Spline3D.
    Expression Indicates force/torque due to damping is input using a solver expression.
    Expression (cx/ctx, cy/cty, cz/ctz) Solver expression that describes the force along the given bushing direction.
    Preload Enter load in the bushing at the start of the simulation.
    Fx Preload force in X direction of the bushing.
    Fy Preload force in Y direction of the bushing.
    Fz Preload force in Z direction of the bushing.
    Tx Preload torque about X direction of the bushing.
    Ty Preload torque about Y direction of the bushing.
    Tz Preload torque about Z direction of the bushing.
    User-defined Activating the check box allows specifying the properties of the bushing using user subroutines.
    User expr Expression defined with the USER solver function with parameters being passed to the user subroutine.
    Use local file and function name Activating the check box enables the definition of properties through a file.
    Local file Local file selection for the subroutine.
    Function Type Function type selection.
    Function name Function name definition.
    Orientation
    Orientation Method Method of orientation. The following choices are available:
    2-Axes Orient marker using the “Axis-Plane” method. Provide a direction for an axis and another direction that lies in a plane defined by the 1st axis and 2nd Axis.
    1st Axis
    Direction Select a direction – X | Y | Z axis.
    Align method Select a method for aligning the chosen axis along a direction – Point | Vector | DxDyDz.
    If Point is chosen, pick a point in the modeling window or through the Advanced selector .

    If Vector is chosen, pick a vector through the modeling window or through Advanced Selector .

    If DxDyDz is chosen, enter the direction cosine values.
    2nd Axis
    Direction Select a plane. The available choice depends on the 1st Axis. For example if Z-Axis is chosen, available choices are the ZX | ZY planes.
    Align method Select a method for aligning the chosen axis along a direction – Point | Vector | DxDyDz.
    If Point is chosen, pick a point in the modeling window or through the Advanced selector .

    If Vector is chosen, pick a vector through the modeling window or through Advanced Selector .

    If DxDyDz is chosen, enter the direction cosine values.
    1-Axis Orient marker using the 1-Axis method. Provide a direction for an axis. MotionView will orient the other axes automatically. This option can be used when only one axis direction is of importance.
    1st Axis
    Direction Select a direction – X | Y | Z axis.
    Align method Select a method for aligning the chosen axis along a direction – Point | Vector | DxDyDz.
    If Point is chosen, pick a point in the modeling window or through the Advanced selector .

    If Vector is chosen, pick a vector through the modeling window or through Advanced Selector .

    If DxDyDz is chosen, enter the direction cosine values.
    Angles Orient marker using the euler angles. Provide three sequential rotations about Z-X’-Z” axes. Where X’ is the new X after the first rotation (about the Z axis) and Z” is the newly oriented Z axis after the first two rotations.
    Z Rotation in degrees about the Z axis with respect to the Ref Marker.
    X’ Rotation in degrees about the new X axis after the first rotation about Z.
    Z” Rotation in degrees about the new Z axis after the second rotation about X’.
    Ref Marker Reference marker about which the marker is oriented.
    DC Display the direction cosine matrix. The DC matrix shows the unit vector direction of each of the axes of the marker.
    Appearance
    Visible Controls the visibility of entity in the modeling window.
    Note & Tags
    Note Optional descriptive note.
    Attachment Candidates Add tags for the entity as possible attachments to Systems/Assemblies/Analyses.
Extended notes:
  1. Bushing is a force element that applies action reaction force on two bodies based on spring-damper equation in six directions. They do not include cross-coupling effects.
  2. Bushings can be used to represent flexible mounts, isolators, and so on.
  3. Linear bushings are written to MotionSolve as <Force_SpringDamper (XML) or SpringDamper (msolve). When any stiffness or damping is not linear, bushing is written as a <Force_Scalar_TwoBody (XML) or SForce (msolve).