Following is the procedure for setting up a springback analysis using QuickSetup/Springback:

1.         Read in the blank results.

The blank results are obtained from a draw simulation. They are output as a .dynain file after each draw simulation. The user may read in the .dynain file by selecting Blank from the QuickSetup/Springback tool GUI and then selecting Import Mesh from the Define Blank dialog box.

2.         Trim the blank.

If no trim operation is involved, the user may skip this step and continue with Step 3. Refer to Section 10.9.6 for more information about blank trimming.

3.         Define blank parameters.

The user needs to define the initial blank material and thickness. The blank parameters are required for the solver to perform initialization prior to springback analysis. These blank parameters should be similar to the blank parameters used in the draw simulation. After the initialization, the thickness, stress and strain stored in the .dynain file will be used as the initial blank parameters.

4.         Select type of implicit method and coarsen options.

5.         Define implicit parameters.

There are appropriate default implicit parameters which are good for all springback analysis. The user may need to adjust implicit parameters accordingly. Refer to the LS-DYNA Keyword User’s Manual for a detailed explanation of all the implicit parameters following the listed cards.

Note: Control cards list different solver versions.

6.         Control rigid body motion.

The user needs to define appropriate constraints on the blank to eliminate the six rigid body motions. This is done by using the Springback Constraint option in the Implicit Parameter dialog box (Figure 9.4.2).  eta/DYNAFORM will prompt the user to select the constraint nodes.

For most applications, 3 constraint nodes are recommended for springback analysis. The chosen 3 constraint nodes should be well separated from each other and away from the edges and flexible areas in the part.  The first constraint node will lock the three translation degrees of freedom and define the reference point in the springback model.  The springback displacement is zero at the first constraint node. The second constraint node will lock the Y- and Z- translation, while the third constraint node eliminates the translation in Z-direction. For detailed information about springback analysis, contact eta/DYNAFORM’s Technical Support at support@eta.com.