Figure 6.3.1 shows the interface of MSTEP. The method of defining tools is similar to method described in Quick-Setup. The Sheet part is the final part geometry and is required as input for MSTEP calculation. The tools marked with blue color are optional input tools.

Figure 6.3.1  The Analysis GUI for MSTEP

Note:   Red indicates that the sheet is not defined. The user must define it to complete the job. Blue indicates that the Bead, Blank Holder, Pad, and Curve Binder are not defined. The user may define these as an option. Green indicates that the flat binder is defined.

The user may enter MSTEP after completion of Preparation, or enter it directly from BSE menu. If the user enters MSTEP after completion of Preparation, the Sheet and the tools defined accordingly will turn to green, which means the corresponding tools are defined.

The Import Results option is used to import the MSTEP calculation result into the current database.

BLANK MESH

Import the flat blank mesh to the current database.

BINDER MESH

Import the blank mesh generated on the surface binder.

FEATURE LINE

Import the feature line (boundary) on the blank surface.

AUTO TIPPING

Auto Tipping for part model before MStep calculation. The Tipping result will be recorded in Tipping page of preparation.

KEEP INPUT FILE

Keep input file in the current working directory.

AUTO SAVE

Automatically save the current database file.

DEFINE SHEET MAT.

Define material property for the defined sheet.  

CONSTRAINT

Define constraints for the final forming part. Please refer to Preprocess / Boundary Condition / Constraints for definition of constraint set. The modified MSTEP supports the constraint definition under a local coordinate system, as illustrated in Figure 6.3.2. After the constraint is created, the two function options for defining LCS will be highlighted. Refer to Coordinate System for detailed description.

Figure 6.3.2  Constraints dialog box

ADVANCED

Allow the user to edit default parameters related to MSTEP setting illustrated in Figure 6.3.3.

ACCURATE

This function allows the user to perform MSTEP on blank with the accurate finite element inverse approach (one-step method). If the user selects this option, the Force and Control Parameter options will be enabled for the user to define parameters such as Binder and/or Pad holding force, convergence tolerance and Restraint Condition.

FAST

This function allows the user to perform MSTEP on part with elastic method. If the user selects this option, the Force and Control Parameter will not be enabled.

In the MSTEP Setting dialog box, the user can choose one of the following Analysis Methods: Accurate and Fast. In accurate analysis, both plasticity and elastic deformation of the blank are considered, in additional to all other boundary conditions such as friction and drawbead(s). In fast analysis, the elastic deformation is considered. The result obtained using Accurate method is much better than Fast method for formability cases where large blank deformation takes place. Of course, the solving time of Accurate method is longer than the Fast method.

FORCE

Binder Hold: Define amount of blank holder force. The default blank holder force is 20000 Newton.

Pad Hold: Define amount of pad force. The default pad force is 20000 Newton.

CONTROL PARAMETER

Max. Iteration Steps: Define the Max. iteration steps during calculation. The default max. iteration steps is 200.

Disp. Convergence: Define the displacement convergence for calculation. The default displacement convergence is 1.0e-003.

Friction: Define the friction between the blank and tools. The default friction is 0.125.

RESTRAINT CONDITION

Allow the user to adjust the restraint condition applied on boundary. Free: no restraint; Low: 20%; Medium: 40%; Strong: 70%; User-defined: allow the user to define the force.

Figure 6.3.3  MSTEP Setting

RUN MSTEP

The user may submit the current setting to solver for calculation.

FORMABILITY REPORT

This option is only highlighted after the MSTEP submits for calculation. After the user estimates the part outline and analyzes the formability, this function will automatically use the Post-processor to deal with the forming results rapidly and export the analysis result report, as illustrated in Figure 6.3.4.

Note: This function is only available when the MSTEP solver is used for formability analysis.

Figure 6.3.4  Formability report dialog box

Post Analysis Option

There is one defining button behind each analysis option, which allows the user to set the scope of contour for the corresponding analysis option, as illustrated in Figure 6.3.5. Refer to the eta/POST User’s Manual for detailed description of each option.

      Thickness: Evaluate the forming quality through thickness of different areas of part.

      Thinning: Evaluate the morphing quality through thickness variation.

      Thickness Strain: Evaluate the morphing quality through thickness strain.

      Major Prin. Strain: Evaluate the morphing quality through major prin. Strain.

      Min Prin. Strain: Evaluate the morphing quality through min prin. Strain.

      Strain Tensor is used to estimate the morphing quality.

      FLD is used to evaluate the formability of blank.

Output Report Type

This option offers two report formats: PDF format and JPEG format.

Open Post

Once this option is toggled on, the program will automatically open the corresponding postprocessor by sequence according to the selection of postprocessor analysis options and read in the analysis results. The program will open as many postprocessors as the post analysis options selected by the user.

Apply

This button is only highlighted after the user uses MSTEP for analysis solution. Clicking this button will cause the program to automatically use the postprocessor to read in the .dynain file, show the results from four different angles in the report according to different postprocessor analysis options, and mark the maximum and minimum values of contour results on the part model, as illustrated in Figure 6.3.6.

View

This button is only highlighted after the user accepts the selection and applies it. The user is allowed to view the generated report.

Figure 6.3.5  Contour setting dialog box

OUTLINE

Click this button to create and edit outline. Refer to Section 6.5 for detailed description.

Note: This function is only available when the MSTEP solver is used for formability analysis.

BLANK NESTING

Click this button to perform part nesting. Refer to Section 6.6 for detailed description.

Note: This function is only available when the MSTEP solver is used for formability analysis.

EXIT

Click this button to exit the MSTEP interface.

Figure 6.3.6  FormabilityReport (PDF)