BOUNDARY CONDITIONS
The functions of the BOUNDARY CONDITIONS MENU create and verify constraints and loads on finite element models. The functions in the BOUNDARY CONDITIONS MENU are shown in Figure 6.7.1.
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LOADING OPTIONS
The LOAD SET dialog window displays, see Figure 6.7.2.
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SHOW SPC ON
Toggles SPC (single point constraint) ON/OFF, see SPC OPTIONS.
1. CREATE FORCE on selected nodes.
Toggle FORCE on.
Select CREATE.
Enter load set number in the next dialog window.
Define node force or moment, see Figure 6.7.3.
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DOF
Degree of freedom, the meaning of these numbers is as follows:
1 - X (Force will be applied in X direction)
2 - Y (Force will be applied in Y direction)
3 - Z (Force will be applied in Z direction)
4 - RX (Moment will be applied about X direction)
5 - RY (Moment will be applied about Y direction)
6 - RZ (Moment will be applied about Z direction)
LOAD CURVE ID
Load curve describes motion value versus time, see Section CREATE CURVE UTILITIES/LOAD CURVE/CREATE CURVE.
SCALE FACTOR
Load curve scale factor.
Select OK in Figure 6.7.3 to select the nodes to load. See Figure 6.4.2 for selecting nodes.
Select CANCEL in Figure 6.7.3 to exit.
2. CREATE PRESSURE on selected elements.
Toggle PRESSURE on.
Select CREATE.
Enter load set number in the next dialog window.
Define element pressure see Figure 6.7.4.
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LOAD CURVE ID
See CREATE FORCE.
SCALE FACTOR
See CREATE FORCE.
BIRTH TIME
Time imposed motion/loading is active.
Select OK in Figure 6.7.4 to select element to load.
Select CANCEL in Figure 6.7.4 to exit.
The following three functions are used for both loading node force and element pressure.
DELETE
A DYNAFORM Question dialog window appears, see Figure 6.7.5.
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Select YES to delete the last selected load set.
Select NO to reject the choice.
DEFINE
Add more nodes or elements to a selected load set.
REMOVE
Remove some selected nodes/elements from a load set.
SPC OPTION
This function allows the user to create and/or modify the SPC options. The SPC SET dialog window appears, see Figure 6.7.6.
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SHOW SPC ON
Toggles SPC ON/OFF to show the current SPC set.
SHOW FORCE ON
Toggles defined force ON/OFF to show the current load force.
1. CREATE SPC SET
Select an SPC type. There are seven types of degree of freedom in LS-DYNA:
1. X-Translation
2. Y-Translation
3. Z-Translation
4. X-Rotation
5. Y-Rotation
6. Z-Rotation
7. All Transformation
The following menu (Figure 6.7.7) provides the ways to define one or several constraints.
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Select CREATE.
Enter the SPC Set ID Number in the next window.
Select nodes to constrain.
2. DELETE SPC SET
Select an SPC set from the list.
Select DELETE.
Confirm the delete in the DYNAFORM Question window (Figure 6.7.8).
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3. DEFINE SPC
Select a set from the list.
Select a type.
Select DEFINE.
Select nodes. More nodes with the selected degree of freedom will be added to the highlighted SPC set.
4. RELEASE SPC
Remove some nodes from the selected SPC set.
CLEAR SPC
Remove all nodes from a selected SPC set. A DYNAFORM Question window is displayed, see Figure 6.7.9.
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Select YES to delete all SPC.
Select NO to reject the choice.
INITIAL VELOCITY
This function allows the user to define and assign linear or angular velocities to selected nodes. See Figure 6.7.10.
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SHOW SPC ON
See SPC OPTION.
SHOW VELOCITY ON
Toggles defined velocity set ON/OFF.
DEFINE
Create velocity set.
Select DEFINE.
Enter the initial velocity in the INTIAL VELOCITY dialog window, Figure 6.7.11.
Select nodes.
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REMOVE
Remove some defined nodes from selected velocity set.
CLEAR
Remove all nodes from the selected velocity set. A DYNAFORM Question window appears, see Figure 6.7.12.
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LIST
There are two choices:
1. ALL NODE
All nodes with an initial velocity are highlighted with an arrow.
2. NODE
The selected initial velocities of nodes are listed in the prompt window.
RIGID BODY STOPPER
This function allows the user to define the rigid body stopper. The rigid body stopper provides a convenient way of controlling the motion of rigid tooling in metal forming. For a detailed description, refer to the LS-DYNA User's Manual. The options are shown in Figure 6.7.13.
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Enter the value in the field to define the distance from the upper stopper (or lower stopper) to the master part.
Select CREATE. The SELECT PART dialog window is displayed. The user can select a part as the master part.
Select DELETE to delete the defined stopper, see Figure 6.7.14.
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After changing the UP or DOWN value, select MODIFY. The user can change the position of the rigid body stopper.
Select SHOW STOPPER ON window to show a stopper in the list.