The Process definition page includes the basic setup of process parameters. It includes stamping speed, blank holding force, forming time, etc. The user may change process parameters according to the actual stamping condition. Moreover, the user may add or delete any process. The basic process setup interface is shown in Figure 8.3.59.

Figure 8.3.59  Process definition page

PROCESS LIST

On the left of the process definition page, all defined process names are listed in the window of Stages. The current process name is highlighted in the list. The user may click another process from the list to switch the current process. The default process is specified according to the defined process type. For example, if Single Action process is chosen, closing and drawing are created as the default process. There are also default settings for the basic parameters such as stamping speed, blank holding force, stamping time, etc. Usually, few parameters are modified.

ADD STEP

This function allows the user to add a new step in the current setup. The user may click the Add button to display the new step interface illustrated in Figure 8.3.60.

Figure 8.3.60  New process interface

NAME

Allows the user to name the current step. Default step names are step1, step2, step3, etc. The user may define a unique name for each step for the ease of identifying the process.

DEFAULT SETTING

Allows the user to select a default setting for the new step. In default setting, the user may select the program default parameters for the new step. Otherwise, the user may choose to use the parameters of any defined step.

USE SETTING OF STEP: New step adopts parameters of an existing step. The user may select an existing process from the pull-down list.

USE DEFAULT SETTING: Uses system default parameters to define a new step.

INSERT POSITION

The user is allowed to insert a new stage before or after any stage.

Note: The step position cannot be modified after inserting the step.

DELETE STEP

This function allows the user to remove the current step from setup. The user may select a step from the step list as the current step, followed by clicking the Delete button to display the dialog box illustrated in Figure 8.3.61. Click on the OK button to delete the current step, or the Cancel button to abort the delete operation.

Figure 8.3.61  Delete process dialog box

STEP NAME & TYPE

NAME

Displays name of the current step. The user may type in a new name in the input data field of Name.

HYDRO

Allows the user to access Hydroforming functions when activated.

TOOL CONTROL

This function is used to control the action of tools define travel speed, blank holding force, travel curve, etc. in the current step. A typical tool control option is illustrated in Figure 8.3.62.

Figure 8.3.62  Tool Control Option

TOOLS

List all the defined tools.

ACTION & VALUE

This group lists all tool control options. Each tool can be controlled by one of the following options: Non-active, Stationary, Velocity, Displacement, Force and Pressure.

NON-ACTIVE

Defined tool is not used in this stage.

STATIONARY

Defined tool is stationary in the current stage.

VELOCITY

The motion of the defined tool is controlled by a velocity curve in the current stage. The user may select one of the standard velocity curve options: Trapezoidal, Sinusoidal, Sin.W-H, Triangular, and Variable. The standard velocity curves are illustrated in Figure 8.3.63. The user may type in the peak velocity in the data input field of selected tool. The default velocity of die for the drawing process is set as 5000 mm/s. For the closing process, the default velocity of binder is set as 2000 mm/s.

 

(a)  TRAPEZOIDAL                             (b)  SINUSOIDAL

 

(c)  SIN.W-H                            (d)  TRIANGULAR

Figure 8.3.63  Types of standard velocity curves

If the user-defined Variable curve is chosen, an Edit button is activated to enable the user to define travel curve using the Load Curve dialog box.

DISPLACEMENT

Tool travel of this stage is controlled by displacement-time curve. The user clicks the Edit button to create displacement-time curve. The procedure is similar to those described in the velocity curve section.
FORCE

Force is applied to selected tool of current stage in closure and/or drawing process. There are three types of force control: Constant, vs. Time and vs. Displacement. If the constant force option is chosen, a constant force value is required. For the variable force options, the user clicks the Edit button to create force- time curve or force-displacement curve.

 This button is activated when force control is selected. The user may use this function to limit the maximum displacement of tools along their working directions. When the force is applied on the binder ring, this function can prevent removal of the binder ring and crushing of the blank due to insufficient or excessive binder force. After clicking on this button, the user can set the corresponding parameters. The interface is illustrated in Figure 8.3.64. The user can set the Upper bound and Lower bound of rigid body stopper to constrain.

Figure 8.3.64  Rigid Body Stoppers dialog box

NON-ACTIVE: The rigid body stopper is non-active.

DISPLACEMENT: Defines the displacement limit of this tool. The user may enter a constant or define the curve.

VELOCITY: Defines the velocity characteristic of the tool. The user can select different types of curves or define curves. The program will automatically convert it into displacement curve.

    Buttons show the initial letter, which indicate: no constraints, only constrain upper bound, only constrain lower bound and constrain both.

Please refer to *CONSTRAINED_RIGID_BODY_STOPPERS keyword in LS-DYNA Keyword Manual for a detailed description.

PRESSURE

Applies pressure on the selected tool in the current stage. The defined pressure curve is converted into a force curve during output of decks.

USER DEFINED CURVE

In each setup, all the defined curves are managed by the curve editor. The user may create, import, edit the existing curve using the function provided in the Load Curve dialog box illustrated in Figure 8.3.65.

Figure 8.3.65  Edit Load Curve dialog box

IMPORT CURVE

Allows the user to import a file containing curve data. The extension of curve files is “.cur” or “.csv”. The curve file is defined according to the standard LS-DYNA keyword format.

A typical curve format is shown in Figure 8.3.66.

Figure 8.3.66  Typical curve format

EXPORT CURVE

Allows the user to export current curve to a text file with “.cur” or “.csv” extension. Click the Export button to display the export curve dialog box, followed by typing in the name of file. Then, click the Save button to store the file in the selected folder.

INPUT

This page displays data the points of the current curve. If no curve is defined, the user may create a new curve by entering point coordinates. The user may modify data points of an existing curve using functions such as add, delete, insert and clear.

ADD: Allows the user to add a data point at the end of curve. Click the Add button to create two empty input data fields which are highlighted in yellow. Next, the user may key in data points in the input data field, followed by hitting the Apply button to complete the operation.

INSERT: Allows the user to insert a data point after current data point. Prior to clicking this button, the user may use the mouse cursor to choose the current data point. The selected data point is highlighted in yellow. Next, click the Insert button to create two empty input data fields, followed by typing in the data point and hit the Apply button to complete the operation.

DELETE: Allow s the user to remove the current data point.

CLEAR ALL: Allows the user to clear all data points in the current curve.

APPLY: The user may click the Apply button after performing add or insert point operation. The curve is refreshed and displayed in the curve display window.

FORMULA

This page allows the user to create curve using mathematic formula such as simple, quadratic, cubic, and sin (cos). When defining FLC curve, the Keeler’s empirical equation is used.

Figure 8.3.67 Formula Page

TYPE: Allows the user to select a type of formula used to create a curve. Types of formula includes: Simple, Quadratic, Cubic, Sin and Cos, etc.

INTERVAL: Allows the user to specify interval of abscissa. Default value varies according to the type of selected formula.

ABSCI-START: Allows the user to specify start point of abscissa. Default value varies according to the type of selected formula.

ABSCI-END: Allows the user to specify end point of abscissa. Default value varies according to the type of selected formula.

PARAMETER: Allows the user to input required parameters for each formula. After a formula is chosen, the expression of the formula is displayed in the interface. For example, expression of Quadratic formula is: . To create quadratic curve, the user must define parameters A, B, C and D.

APPLY: After defining parameters, the user may click the Apply button to create curve. The created curves are displayed in the curve display area, while data points of the curve are listed in the Input page.

OPERATION

This page allows the user to perform additional operation to the curve, such as Translate, Scale and Negate.

Figure 8.3.68  Curve Operation

MODE: Defines the curve operation mode, including Scale, Translate and Negate.

PARAMETER: The user may input curve operation parameters in the input data field. For example, the user needs to individually key in the scale factors for abscissa and ordinate to scale or translate a curve. The user can only negate a curve on the Y-axis.

APPLY: After specifying operation parameters, the user may click the Apply button to complete the operation and refresh the curve displayed in the curve display area.

CLIPBOARD

This function allows the user to temporarily save the current curve to the clipboard. The user may load the curve saved in the clipboard into the current curve interface. The user may also compare the curve in the clipboard and the current curve. The clipboard interface is illustrated Figure 8.3.69.

Figure 8.3.69  Clipboard Interface

DELETE: Removes the selected curves from clipboard.

CLEAR All: Removes all data stored in clipboard.

RESTORE: Allows the user to select curves from the clipboard and restore as the current curve. If current curve is defined, the program will prompt the user to use the curve in the clipboard to overwrite the current curve. The program displays a dialog box illustrated in Figure 8.3.70 to prompt the user for confirmation.

Figure 8.3.70  eta/DYNAFORM Question dialog box

BACKUP: Copies the current curve to the curve clipboard. The program automatically adds a copied curve in the clipboard. All curve information in the clipboard is displayed.

NO.: ID number of curves in clipboard.

TYPE: Type of curve such as time curve, stress-strain curve and FLC curve..

PNTS: Number of points on the curve.

STATUS: The user may control whether the curve in the clipboard is displayed in the show curve area. If the option is selected, the curve is displayed in gray in the curve display area (current curve is displayed in blue).

Note: The curve data on the clipboard is not saved in database file. After the user exits eta/DYNAFORM, all curves in the clipboard are automatically removed.

TOOLBAR OF CURVE EDITOR

The tool bar is displayed at the top of the curve display area. The user may operate the curves by using the functions provided in the tool bar. Tool bar interface is illustrated in Figure 8.3.71.

Figure 8.3.71  Curve Tool Bar

INSERT POINT

This function allows the user to insert a point on the curve. After clicking this button, the user may hover the mouse cursor to the desired location on the curve and click the left mouse button to insert a point.

MOVE POINT

This function allows the user to move a point on the curve. After clicking this button, the user may place mouse cursor on any location near the curve in the display area. The point that is the closest to the cursor is highlighted with a small circle. The user clicks the left mouse button to select the point and the circle is turned to red. The user may click and drag the mouse to move the point to a desired location on the curve display window. Release the left mouse button to place the point at the new location. A typical move point operation is illustrated in Figure 8.3.72.

Figure 8.3.72  Move Points on the Curve

DELETE POINT

This function allows the user to delete points on a curve. After clicking this button, the user may move the cursor to a point on the curve and click the left mouse button to delete the point from the curve.

UNDO

Allows the user to undo the previous operation.

SHOW ALL POINTS

This function displays a small circle on each point on the curve.

SHOW CURSOR LINE

This function allows the user to show cursor line.

PAN

This function allows the user to pan the curve in the curve display window.

ZOOM BY WINDOW

This function allows the user to zoom in on the curve by window selection. After clicking this function, the user needs to click and drag the left mouse button to define a rectangle region in the curve display window. Release the mouse button to zoom in on the curve.

ZOOM BY DRAG

This function allows the user to zoom the curve view by dragging the mouse. The user clicks the left mouse button in the curve display window, holds the mouse button, and moves the mouse downward to zoom out. Move the mouse upward to zoom in the curve.

FIT VIEW

This function is used to adjust the view center and scale automatically to display the entire curve. Allows the user to fit the entire curve in the curve display window.

DURATION

This function is used to control the duration of the current stage. The duration interface is illustrated in Figure 8.3.73. The user may select one of the four methods to define duration: Time, Travel, Closure and Until Home. Each of these four methods has its own advantages and requirements for different forming stages. The user may select an appropriate control method according to the requirement of the current setup.

Figure 8.3.73  Define Closure

DURATION TYPE

The user may select a control type from the Type pull-down menu.

TIME: Allows the user to define a time to control the current stage calculation time. This method is usually used in hydroforming simulation. The user may enter a time value in the input data field.

TRAVEL: Allows the user to specify tool travel distance along the working direction. The user needs to select a reference tool from the tool list illustrated in Figure 8.3.74. Then, define the displacement of the tool along its working direction. The time of travel is automatically computed by the program.

Figure 8.3.74  Travel control stage time

Note: The working direction can be acting in either negative or positive direction of the axis. It is possible to set a negative value to indicate the stage time is controlled by the tool travel distance along the opposite direction of its working direction. In Sheet Forming, working direction should be assigned for all tools.

CLOSURE: Allows the user to choose closure gap required to between two tools. The user needs to select two reference tools from the tool list illustrated in Figure 8.3.75.

Figure 8.3.75  Closure control stage time

FULLY MATCH: This option should be selected when the mesh of two selected tools are not created using physical offset. It is not required for the tools created using physical offset.

GAP: Allows the user to specify the distance from complete closure of the two selected tools to stop simulation of current stage. The calculation time is based on the mesh of the two tools, hence blank thickness has to be taken into account. If physical offset algorithm is chosen, the blank thickness is defined as the gap to calculate the closure time.

Note: When using two tools’ closure option, one of the tools has to be stationary, while the other must be controlled by velocity/displacement.

UNTIL HOME: Facilitate the movement of selected tool to home position. The user needs to select a moving tool from the tool list as illustrated in Figure 8.3.76, or select <All> for all tools.

Note: If <All> is selected, the program will automatically calculate the tool motion curve and make all the tools with defined motion return to HOME position. This function is mainly used for flanging of multiple tools simultaneously.

Figure 8.3.76  Until home

OUTPUT D3PLOT FILE CONTROL

This function allows the user to define the time interval for outputting D3plot files. The D3plot files are output at equal time intervals by default. The user may also insert some required special frames. Sheet Forming provides four D3plot output control methods.

Note: The special frames can only be inserted when the velocity or displacement of tools are defined in this stage.

CONTROL TYPE

The four D3plot output control methods are: Total number, List from start, List from end and Time interval.

Total number

After inputting the total number of frames, the program automatically calculates the time interval and outputs it to the deck.

List from start

The user may specify the distance list between tool and the start point to insert some special frames, as illustrated in Figure 8.3.77. The user may output special frames according to a certain order. For example, if it is from 0 to 10 and the step is 2, then fames will be output at 0, 2, 4, 6, 8, 10, all measured in millimetre unit.

Figure 8.3.77  Add special output frames

ADD: The user may click this button to add special frames. After clicking this button, the program will list the corresponding distance value in the textbox on the left side according to the given conditions. If there are values in the textbox, the program will insert or add the new value according to the conditions input by the user.

SET: After inputting the given conditions, click this button to clear the values in the textbox and replace with new values.

SORT: Sort the distance value input by the user.

DEFAULT: Click this button to show the default special frames.

OK: Save the current setting result and exit the special frames setup dialog box.

CANCEL: Exit the setup dialog box without saving the current setting.

List from end

The operation of this function is similar to the one of List from start.

Time interval

The user may directly input the time interval. The program will output a frame result after reaching the specified incremental time interval.

Note: The user may directly enter the distance value in the textbox and press the Enter button to confirm. After exiting this dialog box, the program will automatically delete the illegal characters and manage the order of distance values.

After the user adds special frames, the program shows the information about the added special frames on the main interface of the current stage. An example is illustrated in Figure 8.3.78.

Figure 8.3.78  D3plot File of Special Output Time Point

HYDRO MECHANICAL

This function allows the user to set parameters for hydro mechanical forming. The user may select the Hydro Option illustrated in Figure 8.3.79.

Figure 8.3.79  Hydro Forming

HYDRO MECH. PARAMETERS

In Hydro mech. field illustrated in Figure 8.3.80, the user may specify internal fluid pressure vs. time curve, boundary and direction of applied internal fluid pressure.

Figure 8.3.80  Hydro Mech. parameters setup

ABOVE: In press coordinate system, fluid pressure is applied on the top of blank illustrated in Figure 8.3.81.

Figure 8.3.81   Fluid pressure is applied on top of blank

BELOW: In press coordinate system, fluid pressure is applied on the bottom of blank illustrated in Figure 8.3.82.

Figure 8.3.82  Fluid pressure is applied on bottom of blank

BY NORMAL: Direction of fluid pressure is defined according to normal vector of blank element. The user needs to check and ensure the element normals are consistent. Otherwise, the setup is incorrect.

PRESSURE: Set up internal fluid pressure vs. time curve. This parameter is essential in sheet hydro forming. The user may click P = 0 button to key in values of internal fluid pressure vs. time curve in the define dialog box illustrated in Figure 8.3.83.

Figure 8.3.83  Hydro Pressure-Time Curve Defines

CONSTANT: Define fixed internal fluid pressure. The user may key in a constant fluid pressure in the Pressure input data field.

CYCLE: Define analysis cycle time of fluid pressure. By default, cycle is set as 200.

TIME VARIABLE: Define variable internal fluid pressure. The user may click the Edit button to display the Load Curve definition interface. For a detailed description of curve definition, refer to Chapter 14.

MASK: Assign boundary of applied fluid pressure using closed loop line. Applied fluid pressure can be either inside or outside of the boundary. By default, fluid pressure is applied on all blank elements. Click the Entire button to display the Mask dialog box illustrated in Figure 8.3.84.

Figure 8.3.84  Define fluid pressure boundary

INSIDE Apply fluid pressure inside of the defined boundary line.

OUTSIDE Apply fluid pressure outside of the defined boundary line.

PROJECTING DIRECTION: Allow the user to select project direction. eta/DYNAFORM adopts one closed loop curve for the definition of fluid pressure, hence it is not necessary to position the curve on top of blank. The assigned curve is needed for projection onto the blank. Therefore, the project direction for closed curve is required. After the user clicks this button, the Direction definition dialog box is displayed. A detailed description of this function is provided in Section 8.3.4.3. The default project direction is Z-axis of the working coordinate system.

DX DY DZ: Display the coordinates of the end point of project vector. Default vector starting point is the origin of working LCS.

POINTS: Display the number of points along curve.

LINES: The user may define region subjected to applied fluid pressure by defining a closed loop curve. After clicking this button, the Select Line dialog box is displayed.

POINTS: If no curve is provided in the database, the user may define a closed loop curve by clicking this button to create a line using points.

Note: When defining boundary of applied fluid pressure, it is recommended to select closed loop curve or a closed end point. If the curve/point is not closed, the program automatically closes curve and point.

CLEAR: Remove current defined line. The program displays a confirmation dialog box illustrated in Figure 8.3.85.

Figure 8.3.85  Confirmation dialog box

OK: Accepts the current setup and exits the dialog box.

CANCEL: Aborts the current setup and exits the dialog box.

If the region subjected to applied fluid pressure is defined, the Partial is displayed on the button next to Mask. This indicates that only some of elements on the blank are subjected to applied fluid pressure.

SINGLE POINT CONSTRAINTS (SPCs)

This function allows the user to define single point constraint. Click on the SPCs(0) button to display the dialog box as shown in Figure 8.3.86. The user should select the constraint type prior to clicking the New button to apply constraint to selected nodes. The node IDs with defined constraint are listed in the box illustrated in Figure 8.3.86. The highlighted node with defined constraint is marked on the display screen. The currently selected constraint node is marked with angular brackets.

     

Figure 8.3.86  Single Point Constraints dialog box

The types of constraint include:

All:                       Constrain all the degrees of freedom.

Hinged (UVW):    Hinged constraint. Constrain translation of all directions.

GuideW (UV):      Constrain translation along U and V direction.

GuideV (UW):      Constrain translation along U and W direction.

GuideU (VW):      Constrain translation along V and W direction.

PlaneVW (U):       Constrain part motion on VW-Plane only.

PlaneWU (V):       Constrain part motion on WU-Plane only.

PlaneUV (W):       Constrain part motion on UV-Plane only

SymUW (Vuw):    Define part symmetry about UW-Plane.

SymVW (Uvw):    Define part symmetry about VW-Plane.

User defined:        Allow the user to customize constraints.

If User defined option is selected, the user can toggle on any checkbox combination to define translation and/or rotation constraints. U, V and W indicate translation constraints in X, Y and Z, respectively. u, v and w indicate rotation constraints in X, Y and Z, respectively.

T:                         Translation constraints.

R:                         Rotation constrains.

NEW:                   Select nodes.

MODIFY:             Modify constraint type after selecting constraint points.

DELETE:             Delete the selected constraints.

DELETE ALL:      Delete all constraints.

OK:                      Accept defined constraints and exit SPCs dialog box.

CANCEL:             Reject defined constraints and exit SPCs dialog box.