In the Blank page, the user can define Part, Material, Thickness and
Property of blank. Furthermore, the user may define weld line for tailor-welded
blank application, contact interface for laminated sheets, blank symmetry
constraints and single point constraints, etc. The interface of the Blank page
is illustrated in Figure 8.3.16.
Figure 8.3.16 Interface of Blank definition
GEOMETRY
PARTS
As shown in Figure 8.3.17, the Part field
allows the user to assign a part as blank for stamping simulation. After
clicking the Define geometry… button, the Blank Generator dialog box
illustrated in Figure 8.3.18 is displayed. Refer
to Section 7.2 for detailed description about defining blank.
Figure 8.3.17 Geometry field
Figure 8.3.18 Blank generator dialog box
After blank parts are defined, the names of
each part are displayed in the Part field. The default material, thickness and
property are assigned for the part. The user may reassign material, thickness
and property for each part.
MATERIAL
The program defines a default type 36 material
for blank part, as illustrated in Figure 8.3.19.
Figure 8.3.19 Define material
Note:If no material is assigned to the
Part, the BLANKMAT is listed in material button. After defining the material,
the material name is displayed on the button.
The user may click button to enter the Material interface illustrated in Figure 8.3.20 to modify or create a material.
Figure 8.3.20 Material definition dialog box
In the Material interface, the user may create, edit, import and output a material, or select a material from the material library.
TYPE: Display the defined
material type. eta/DYNAFORM currently supports the following material types: 1,
4, 12, 18, 24, 36, 37, 39, 64, 103, 106, 113, 122, 123, 125 and 133.
NAME: Display the defined material name.
NEW: Allow the user to create new blank material.
After clicking this button, the list of material types illustrated in Figure 8.3.21 is displayed. The user may select one of the
material types from the list. Once a material type is chosen, the Material dialog
box illustrated in Figure 8.3.22 is displayed.
Figure 8.3.21 Select material type
Figure 8.3.22 Material dialog box
Forming Limit Curve (FLC): This parameter should be defined
if material type 39 is chosen. If no FLC curve is defined, <NONE> is
displayed at the FLC input field. To define FLC curve, click button to display the FLC curve edit dialog
box illustrated in Figure 8.3.23.
Note: The FLC curve defined in Sheet Forming is represented in engineering strain.
In the FLC curve edit dialog box,
the user may enter the FLC data points directly in the INPUT page.
Alternatively, the user may define FLC curve using Keeler’S FLC empirical
equation provided in the Formula page. After entering the n and t values, click
the Apply button to generate the FLC. The FLC curve is displayed in the show
curve interface illustrated in Figure 8.3.23. A detailed description of the curve edit
operation is provided in Section 8.3.4.4.
Note: The user may set strain type in the Operation page. The strain type of the exported FLC curve is the same with the selected strain type. The strain type of the imported FLC curve is determined by the strain type label in file.
Figure 8.3.23 FLC Curve
EDIT: Allows the user to
edit the material parameters listed in the Material dialog box illustrated in Figure 8.3.24.
Figure 8.3.24 Material Edit dialog box
Note: Edit Material and Define Material dialog boxes are basically identical. The user may modify any parameter in the dialog box, except the material type. To change the material type, the user must create a new set of material properties.
IMPORT: Allows the user to
import a material file. The suffix of the file name is “.mat” or other suffix.
By default, Import Material window illustrated in Figure 8.3.25 is displayed when
the button is hit.
Note: For PC users, the extension of material file may be associated with Microsoft Office Access. The “.mat” extension will not be displayed, but the extension of material files may be viewed from the console model. To display the “.mat” extension, the user must delete the association between the “.mat” extension and Microsoft Office Access.
Figure 8.3.25 Import Material window
After selecting a file, the user
may click the Import button to import the selected material and assign it to
the selected blank part.
EXPORT: Allows the user to export and write the
current material into a file. The file is saved with an extension “.mat”. The
Export Material window is illustrated in Figure 8.3.26.
Figure 8.3.26 Export Material window
MATERIAL LIBRARY: This function enables the user to
select the type of generic material library in eta/DYNAFORM. There are four
types of generic material library supported by eta/DYNAFORM. They are
Figure 8.3.27 Material Library Standard
After selecting a regional
material library, the material library GUI illustrated in Figure 8.3.28 is displayed. The user proceeds by selecting
a type of material from the library to be assigned as the blank material.
The Material Library interface
allows the user to conveniently select a type of material. The right key menu
enables the user to expand each node of tree structure. The number listed in
the parentheses next to each material indicates the material type. The
previously selected material type number will be displayed in the parentheses.
Note: The materials in the material library are
only for reference. The user can obtain the detailed material parameters from
the material suppliers. Engineering Technology Associates, Inc. assumes no
liability or responsibility to any person or company for direct or indirect
damages resulting from the use of any information contained in the material
library.
The user-defined material is saved in the user-defined directory. The user can
set the default path of material library from the Option/Material Library menu.
Figure 8.3.28 GUI of Material Library
·
User Defined
This function allows the user to
add, delete, and rename the user-defined material library. The added material
library will be shown in the list of material library. The User Defined Standard
dialog box is illustrated in Figure 8.3.29.
ADD: Add and define the name of the user-defined
material library.
RENAME: Edit the name of the user-defined
material library.
DELETE: Remove the user-defined material
library.
Figure 8.3.29 User Defined Standard dialog box
·
This function allows the user to
reorder the material models within the material strength level. Select a material or group of materials and
use these buttons to move them up or down in the list.
·
Category
Click the right mouse button at
the root node of tree structure to create a new material category, strength
level and type of material. Default material categories are Steel and Aluminum.
The user can assign a name to the new material category, and rename or delete the
material category. As illustrated in Figure 8.3.30, the list of each node is displayed if the
right mouse button is hit.
Figure 8.3.30 The corresponding list of each node
·
Strength Level
The material library allows the
user to classify the following steel grades: Low, Medium, High, Advanced High,
Hot Roll and Cold Roll. Users can easily manage their own material library.
·
Material Name
The user can click the right mouse
button of Strength Level to define a new material. The Create Material dialog
box illustrated in Figure 8.3.31 is displayed. The user can select material
type and edit material parameters in this dialog box. The default material name
is similar to its title. The user must specify the path of the new material
prior to saving it.
Figure 8.3.31 Create Material dialog box
·
Material Type
The user can click the right mouse
button of Material Name to define or import the new material type. The user can
also click the right mouse button of Material Type to edit or delete material
type. The Create Material Type dialog box is illustrated in Figure 8.3.31, the Import Material dialog box is
illustrated in Figure 8.3.32. After the material is imported, the type of
material number is automatically assigned.
Figure 8.3.32 Import Material dialog box
THICKNESS
By default, the thickness value for blank is
defined in the New Sheet Forming dialog box. The user can edit thickness of
blank in the Thickness field.
PROPERTY
By default, the properties of blank are set as
illustrated in Figure 8.3.33. These blank
properties are good for most stamping simulation.
Figure 8.3.33 Define Blank Properties
ELEMENT FORMULATION: This option allows the user to choose
type of element formulation. Currently, 16 shell element formulations are
supported in eta/DYNAFORM. In addition, thick shell and solid element
formulation are available. The default element formulation is No. 2
BELYSTSCHKO-TSAY shell element formulation. This element formulation is the
most popular and economical one for sheet metal forming simulation. For
springback analysis, it is recommended to select No. 16 Full Integration
element formulation in both draw simulation and springback analysis.
NUMBER OF INTEGRATION POINTS: The default number of integration
points is 5. Increasing the number of integration points through the material
thickness may improve the precision of simulation results. On the other hand,
the simulation time will drastically increase. For draw simulation without
considering springback, the default number of integration points through the
material thickness is recommended. For a draw forming simulation with
subsequent springback analysis, use of 7 or more integration points through the
thickness of the material is suggested.
OK: Save the current setting and exit
the property definition dialog box.
DEFAULT: Use the default value.
CANCEL: Exit the dialog box without
saving the modification of the current setting.
POSITION
This function allows the user to move the position of blank along U, V
and W direction illustrated in Figure 8.3.34. After auto positioning, the movement along
W direction is listed in the Position field.
Figure 8.3.34 Position field
TRANSFORMATION
In multistage forming setup, the user is allowed to translate/rotate
the blank or change the coordinates of blank in the next stage, as illustrated
in Figure 8.3.35. The sequence of translation and rotation is
very important. Usually, it is suggested to carry out rotation operation first
and then translation.
Figure
8.3.35 Transformation
The user may click the Define button in the Blank setup page to enter
the Transformation dialog box, as illustrated in Figure 8.3.36. The added transformation operations will be
displayed in the list. The user can click the arrows to adjust the sequence of
transformation operations, or click the Delete button to delete the defined
transformation operation.
Figure
8.3.36 Transformation dialog box
ADD: add translation, rotation or
LCS2LCS operation.
EDIT: edit the defined translation, rotation or
LCS2LCS operation.
APPLY: add the defined translation,
rotation or LCS2LCS operation to the list.
TRANSLATION: define the direction and
distance of translation. There are three methods to define translation:
1. Enter the distance along U, V and W
directions. The direction of translation and distance is automatically
calculated according to the input. If the Direction button is selected, the
direction of translation is displayed in the dialog box and marked with an
arrow in the display screen. The distance is displayed in the Distance field.
2. Click on the Direction button to define
direction of translation. Then, exit the Direction dialog box and key in the
desired distance in the data input field of Distance. The direction of translation
and distance is automatically calculated according to the input.
3. Click on the 2 Points/Nodes
button, followed by selecting two points/nodes from the display screen. The
direction of translation and distance is automatically calculated according to
the input.
ROTATION: Define rotation axis and angle.
Rotate the model about any axis of the current coordinate system with any input
angle.
LCS2LCS: Conversion of local coordinate
system. The user is allowed to convert the model from one coordinate system to
another. The translation and rotation information is automatically output.
SYMMETRY
This function allows the user to create a symmetry condition for the
blank to reduce simulation time. The user may define either ½ or ¼ symmetrical
condition along the line of symmetry of the blank. ½ and ¼ blank mesh is
required for applying ½ and ¼ symmetrical conditions, respectively. By default,
<None> is displayed in the field of Symmetry type illustrated in Figure 8.3.37,
indicating no symmetry condition is applied to blank. The user may click button to display the Symmetry Plane dialog
box illustrated in Figure 8.3.37.
Figure 8.3.37 Symmetry field
1/2 SYMMETRY
This function allows the user to define ½ symmetrical blank. The
interface is illustrated in Figure 8.3.38.
Figure 8.3.38 Define Symmetry Plane
SYMMETRY AXIS: The
current user defined symmetry plane information is displayed in this field. The
symmetry plane is specified by a point, a vector and WCS direction.
O(0,0): Indicates the
coordinate of starting point of the vector defining symmetry plane.
X(1,0): Indicates either
UW- or VW-plane chosen as symmetry plane.
UW-PLANE: A plane parallel to LCS’s UW-Plane is
chosen as the symmetry plane. The user specifies the location of the plane by
using the Select Points function illustrated in Figure 8.3.38. The position of the symmetry plane is
displayed in O (0, 0), while the direction of symmetry is displayed in X (1,
0). A vector is displayed in LCS’s UW-Plane on the screen to show the symmetry
plane. See Figure 8.3.39 for more details.
VW-PLANE: A plane parallel to LCS’s VW-Plane is
chosen as the symmetry plane. The user specifies the location of the plane by
using the Select Points function illustrated in Figure 8.3.38. The position of the symmetry plane is
displayed in O (0, 0), while the direction of symmetry is displayed in X (0,
1).
2 POINTS ON UV-PLANE: Enables the user to define the
vector of the symmetry plane by selecting two points. The symmetry plane is
parallel to W axis. The first point of the vector specifies the position of the
symmetry plane.
SELECT POINT(S): Allows
the user to select one or two points to specify symmetry plane. If the user
selects UW-Plane or VW-Plane option, only one point is required to specify the
location of symmetry plane. If the user selects the 2 Points on UV-Plane
option, then two points are required to define symmetry plane.
TOLERANCE: Default
tolerance is 0.01. Nodes falling inside the tolerance are assigned the symmetry
boundary condition. The user may increase the tolerance to extend the search
range for nodes near the symmetry plane.
Figure 8.3.39 Define Symmetry
1/4 SYMMETRY
This function allows the user to apply a symmetry boundary condition on
a ¼ symmetry blank. After defining a vector, another vector normal to the
defined vector is automatically created to specify the other symmetry plane. Figure 8.3.40 illustrates a typical definition of ¼
symmetry planes.
Figure 8.3.40 Define 1/4 Symmetry
WELDS
In Sheet Forming, the user can conveniently set up the forming simulation of tailor-welded and composite blanks. After multiple blank parts are defined, the Welds option is activated on the Blank page illustrated in Figure 8.3.41.
Figure 8.3.41 Define Tailor-welded Blank
After the weld lines are defined, the information of weld lines is displayed in Welds list.
ADD WELD
This function allows the user to
select adjacent nodes to define weld element. After clicking the Add button, the
Blank Weld dialog box illustrated in Figure 8.3.42 is displayed.
Note: The node pair of a weld must consist of two separate nodes with different positions. Different nodes with the same position or identical nodes with the same position are not allowed.
Figure 8.3.42 Define Weld dialog box
NODAL PAIRS: Display
number of nodal pairs. After the user selects nodal pairs, the number is displayed
in the data box.
OVERLAP BLANK: The user
needs to select this option for overlap blank. After selecting this option, the
line connecting the nodal pair is normal to its connecting element.
WELD WIDTH: Specify
the width of weld. Default width is 1.0 (mm). If the distance between the selected
node pair is smaller than the default value, weld is defined for the selected
node pair. The user may adjust the width to include the node pairs with a larger
gap.
WELD: The user may click
this button to select node pair. From the displayed Select Node dialog box,
select two rows of nodes required for definition of weld node. After selecting
the nodes, weld as illustrated in Figure 8.3.43 is defined between
nodal pairs.
Figure 8.3.43 Define Weld
Note: If the nodes are offset manually before defining the weld, the user only needs to select the offset two rows of nodes when defining. If the nodes are not offset before defining the weld, the program will automatically offset the selected nodes 0.05 towards their element directions after the user selects the common nodes for two parts and define the offset nodes as weld. This process is automatically completed by the program. The user only needs to select the common nodes for two parts with different materials or thickness, as illustrated in Figure 8.3.44.
(a) Before
(b) After
Figure 8.3.44 Offset Node
CLEAR: This button allows
the user to remove the current defined welds and combine the node pairs of
welds to one node.
FAILURE: The user may define
failure criteria for the weld.
NEVER FAILURE: By
default, the Never Failure option is chosen to ensure weld does not fail during
the stamping simulation.
CONDITIONAL FAILURE: Allows
the user to define conditional failure criteria and its relevant parameters. A
detailed description is available in the LS-DYNA Keyword User’s Manual.
EDIT
This function allows the
user to edit the defined weld. The user may delete the selected nodal pair, add
a new nodal pair, modify weld failure criteria, etc.
CLEAR
After a
weld line is defined, weld information such as number of nodal pairs, failure
criteria of weld is displayed in the weld list illustrated in Figure 8.3.45.
Figure 8.3.45 Welds List
The user
may delete a weld by clicking appropriate button listing the correct number of
spot welds on the line, followed by clicking the Clear button to remove the
current weld definition.
CONTACT
This function allows the user to
define the contact types and contact parameters of single surface, and between
blank parts.
Figure 8.3.46 Define Contact Between Blanks
SINGLE SURFACE
This
option allows the user to define the contact of blank itself and the surface
contact of blank with other parts. The program will automatically decide the
contact place for the model surface.
BETWEEN PARTS
If the
defined blanks are overlapped, Between parts option must be toggled on,
otherwise, the calculation will be wrong. At the same time, the user can modify
contact parameters such as friction coefficient, contact type, etc. As shown in
Figure 8.3.46, if it is not
overlap blank simulation, this option does not need to be toggled on by
default.
ADVANCED
The user
may modify some contact parameters between blanks through advanced options
illustrated in Figure 8.3.47.
Figure 8.3.47 Define Advanced Contact Parameters
CONTACT TYPE: This
function allows the user to select type of contact algorithm illustrated in Figure 8.3.48.
Figure 8.3.48 Define type of contact algorithm
STATIC FRICTION COEF.
Allows the user to define static coefficient
of friction. Default value is 0.125.
VISCOUS FRICTION COEF.
Allows the user to define viscous coefficient
of friction. Default value is 0.
VISCOUS DAMPING COEF.
Allows the user to define viscous coefficient
of damping. Default value is 20.0.
DYNAMIC FRICTION COEF.
Allows the user to define dynamic coefficient
of friction. Default value is 0.
DECAY COEF.
Allows the user to define coefficient of
decay. Default value is 0.