CONSTRAINTS

 

This function allows the user to create and/or modify the constraints. The CONTSTRAINTS dialog box is illustrated in Figure 5.6.6.

Figure 5.6.6 Constraints dialog box

 

SHOW CONSTRAINT

Toggle checkbox on/off to show/hide display of selected CONSTRAINT set.

 

SHOW FORCE

Toggle checkbox on/off to show/hide load force.

 

SHOW ALL

Toggle checkbox on/off to show/hide all Constraints.

 

 

ADVANCED OPTIONS

Toggle checkbox on to access the advanced options for constraint definition.

 

1.         CREATE CONSTRAINT SET

 

            Select a type of constraint. In LS-DYNA, each node is associated with six degree of freedom as listed below:

 

1.     X-Translation

2.     Y-Translation

3.     Z-Translation

4.     X-Rotation

5.     Y-Rotation

6.     Z-Rotation

 

The following drop down menu as illustrated in Figure 5.6.7 provides the basic and advanced approaches for definition of constraints.

 

     

(a)                             (b)

Figure 5.6.7 Type of Constraint (a) Basic (b) Advanced

 

          Select CREATE.

 

          Enter the Constraint Set ID Number in the displayed dialog box.

 

          Select nodes to apply constraints.

 

2.         DELETE CONSTRAINT SET

 

          Select a constraint set from the list.

 

          Select DELETE.

 

          Select Yes to remove the constraint set from the eta/DYNAFORM QUESTION dialog box as illustrated in Figure 5.6.8.

 

Figure 5.6.8 DYNAFORM Question dialog box

 

3.         DEFINE CONSTRAINT

 

          Select a set from the list.

 

          Select type of constraint.

 

          Select DEFINE.

 

          Select nodes. Nodes with the selected degree of freedom will be added to the highlighted constraint set.

 

4.         RELEASE CONSTRAINT

Remove some nodes from the selected constraint set.

 

1.          CLEAR CONSTRAINT

Remove all nodes from a selected constraint set.  A eta/DYNAFORM QUESTION dialog box as illustrated in Figure 5.6.9 is displayed.

 

Figure 5.6.9 DYNAFORM Question dialog box

 

Select YES to remove all constraints.

 

Select NO to reject the choice.