Flexible Body Modify
Right-click flexible body → Modify (shortcut: Double-click)
Lets you modify a flexible body. For example, you can change its modal content or representation to improve the efficiency or accuracy of a Simulation.
For the option: | Do the following: |
|---|---|
Flexible Body | Enter the name of the flexible body to modify. |
Damping Ratio | Do one of the following: ■Accept the default. If you accept the default, Adams Flex applies non-zero damping as follows: ■1% damping for all modes with frequency lower than 100. ■10% damping for modes with frequency in the 100-1000 range. ■100% critical damping for modes with frequency above 1000. ■Clear the selection of default, and then either: ■Enter the scalar damping ratio that you want applied to all modes. ■Enter a function. To get help building the function, next to the Damping Ratio text box, select the More button  . Learn more about Specifying Damping. |
Datum Node | Set the datum node for which you want deformation color changes to be relative to using Adams Flex. Adams Flex considers the deformation to be relative to the origin of the flexible body (its local body reference frame (LBRF) or coordinate system) by default. For example, if you were modeling a cantilever beam in Adams Flex, you could specify that deformations should be relative to the clamped end as is illustrated in the first tutorial, Building and Simulating a Flexible Model, in Getting Started Using Adams Flex. To set the datum node: 1. Clear the selection of LBRF. 2. In the Datum Node text box, enter the number of the desired node. Note: To select a node from the screen, right-click the Datum Node text box, and then select Pick Flexbody Node. Select the node from the screen. The node number appears in the Datum Node text box. |
Generalized damping | Select one: ■Off - Disables the generalized damping. ■Full - Enables the complete generalized damping matrix, including the effects of a resultant damping force. ■Internal Only - Only enables the portion of the generalized damping matrix corresponding to the modal coordinates (that is, ignore the resultant damping force). |
Location | Click to display the Modify Body - Name and Position dialog box and set the name, Adams Solver ID, and location of the flexible body. |
Position ICs | Click to display the Modify Body - Position Initial Conditions dialog box and set the initial position for a flexible body before the simulation starts, just as you can for any part in Adams View. You can set how you want Adams View to calculate these properties as well as define these properties yourself. |
Velocity ICs | Click to display the Modify Body - Velocity Initial Conditions dialog box and set the initial velocity for a flexible body before the simulation starts just as you can for any part in Adams View. You can set how you want Adams View to calculate these properties as well as define these properties yourself. |
Modal ICs | Click to display the Modify Modal ICs dialog box to disable or enable range of modes using a table. Learn About Flexible Body Modal Content. |
Mode Viewing and Animation | |
Mode Number | Enter the number of the mode in the flexible body to view, and then press Enter. The total number of modes in the flexible body appear to the right of the Mode Number text box. When you display a mode, Adams Flex displays its frequency in the Frequency text box. Also, when you display a mode, the mode deformations appear along with the undeformed flexible body. You can turn this off to display only the deformed mode. Learn more about Viewing Modes. |
 | Select to display the next mode. |
 | Select to animate the specified mode to see how it deforms. By default, the animation runs 3 times or through 3 cycles. (Use the Cycles text box (described below) to change the number of cycles.) Note: You can also use the Animation tool on the Main toolbox to animate the entire model containing the flexible body after you've run a simulation. |
 | Select to display the previous mode. |
Frequency | Enter the frequency of the mode you'd like to view, and then press Enter. The mode closest to the specified frequency appears. |
Cycles | Enter the number of times Adams Flex should run the animation. By default, the animation runs 3 times or through 3 cycles. |
Superimpose | Clear to display only the mode deformations. Select to display both the mode deformations and the undeformed flexible body. |
Frames | Enter the number of animation frames. |
Disabling/Enabling Modes (Learn more about Enabling and Disabling Modes.) | |
Enable/Disable | Enable or disable the mode number in the Mode Number text box. If you disable a mode, its mode number and natural frequency appear in parentheses. |
range | Click to display the Enable or Disable a Range of Modes dialog box to disable or enable a group of modes based on either their mode number or frequency. |
auto | Click to display the Auto Disable Modes by Strain Energy dialog box to disable or enable modes based on their contribution of strain energy. |
Substituting Graphics with an Outline (Learn more about Substituting Outline Graphics for the Finite Element Mesh.) | |
full MNF graphics | Select to turn on the viewing of the full MNF graphics; clear to turn off the viewing. |
Outline | Select to turn on the viewing of the Outline. |
 | Select to sketch an outline. To sketch the outline: ■Select nodes on the flexible body using the left mouse button. ■When the outline is complete, right-click. |
Modifying Flexible Body Representation or Modal Formulation Note: Dual-representation or simplified flexible bodies do not directly support contact with any other bodies nor modal force. One would have to use dummy part geometry fixed to the flexible body for contact modeling. | |
One Representation | Selects the flexible body to not be eligible for runtime type switching during a simulation. This is the default setting. |
Dual Rep Start Rigid | Selects the flexible body to be eligible for runtime type switching and will be treated as a rigid body initially for the simulation. Note: When this option is selected and the Inertia Modeling radio button is set to "Rigid Body" or Invariant 6 is disabled in Custom Inertial Modeling, a warning message is issued because these may not be the desired settings. |
Dual Rep Start Flex | Selects the flexible body to be eligible for runtime type switching and will be treated as a flexible body initially for the simulation. Note: When this option is selected and the Inertia Modeling radio button is set to "Rigid Body" or Invariant 6 is disabled in Custom Inertial Modeling, a warning message is issued because these are conflicting settings. |
Flexible Method: Simple Flex | Selects a Simple Flex formulation to be applied to the flexible body and not be eligible for runtime type switching during a simulation. Simple Flex method converts the modal representation into a semi-equivalent multi-force (NFORCE) with multiple rigid body representation. It retains linear compliance of the flex body and some dynamics (that is, damping). The stiffness and damping matrices of the NFORCE is derived from the modal stiffness matrix of the flex body, and the modal Damping Ratio settings. Rigid bodies are created and connected to the NFORCE at the CM and each interface marker of the flex body. The inertia properties of the rigid bodies are derived from Inertia Modeling with Partial Coupling settings for the flex body. This results in some loss of accuracy, but results in a faster solution. Also, flex body contact and modal force (MFORCE) application are not permitted with the Simple Flex method. For more information on this method, see the Solver guide for FLEX_BODY statement with REPRESENTATION option. Flex body animation with the Simple Flex method is limited to showing rigid mesh of flex body while animating the displacement of flex body markers. Thus, the animation of flex body markers may move away from the reference node from a rigid animation of the mesh. Result set components that appear on the Plotting dashboard for Simple Flex method will vary greatly from those of Modal method. The REPRESENTATION and RESULT_FILE_INDEX components are included in the flex body XFORM result set. Typically, these will be constants set to 4 (for Simplified Representation) and 0. Instead of MODES, a NODES component is included which provides the list of node ID that were selected as nodal references on the flex body markers (SELNOD). The kinematics (displacements, velocities and accelerations) of each selected node are included as components. Finally, the kinematics of the rigid body CM is included as components. |
Inertia Modeling | Select a formulation option or select Custom. Learn more about the options. When you select Custom, Adams Flex displays a Custom Inertial Modeling dialog box that lets you set up the invariants that you want selected. |
Setting Plot Type | |
Plot Type | Select a plot type to view in Adams Flex: ■Contour - Sets Adams Flex so that it displays Contour plots. In addition, you can view contour plots in Adams PostProcessor. ■None - Sets to display no plots. ■Both - Sets the display of both contour and vector plots. |
Mode Filter | Select to display the Flexible Body Mode Filter dialog box to exclude nodal deformations from animations to increase animation performance. |
Setting Deformation Scale | |
Deformation Scale | Change the Deformation Scale Factor text box value to change the amount by which a flexible body will displace. For increasing the deformation scaling, type a value greater than 0 in the text box. Changing the deformation scale lets you exaggerate deformations that might otherwise be too subtle to see, or lets you limit the deformations. The default scale factor is 1. Note that setting the scale factor to a value other than 1 can make the joints at the flexible body appear to separate. This is because the motion of a point on a flexible body is the sum of the deformation that has been scaled and a rigid body motion that is not scaled. In addition, if you set the scale to 0, Adams Flex treats the flexible body as a rigid body during animations. |
 | Select to add any comments to help you manage and identify the flexible body. See Comments. |
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 | Select to Modify Flexible Body Connections. |