Dummy Positioning

Position a dummy model using the Dummy Browser.

Dummy Browser

Overview of the Dummy Browser.

From the Safety ribbon, Occupant tools, click the Dummy icon.

Restriction: Only available in the LS-DYNA and Radioss solvers.

This browser is compatible with all LS-DYNA and Radioss Humanetics dummies (encrypted or not encrypted) and also with LSTC dummies.

You can undo and redo actions made in the browser using the Undo and Redo commands on the Restore toolbar.

The Dummy Browser consists of two panes. The first pane displays the dummy structure which consists of the different bodies defining the dummy model. The second pane displays the Entity Editor in which positioning parameters for each dummy articulations can be defined.


Figure 1.
The following data is displayed in the Dummy Browser:
Column Description
Entity List of the dummies and dummy bodies.
ID Displays the dummies and bodies IDs.
Color Displays the body entity colors.

Body color is different from the component color defined in the Model Browser. The body color is activated when a body is in Review mode or when display mode is set on “By Body”.

Entity Editor

The Entity Editor is used to assign, modify and quickly view the attributes defined inside Dummy Browser entities.

In the Entity Editor you can define the H-Point coordinates or apply Global rotations on the dummy to position the dummy in space. The H-Point coordinates can be directly specified in the fields, or by clicking on the blue arrow, which then enables you to select a target location by picking a node in the graphics area.


Figure 2.
Global rotations on the dummy can also be defined. The magnitude of the rotation can be modified, using the up and down arrow buttons. Moreover, you can control the increments of the operations by changing the Increment value.


Figure 3.

The Entity Editor is also used to modify the position of bodies. You can directly define the angle of rotation to apply in each axis of rotations in which the selected body is able to move.

The magnitude of the rotation can be also modified, using the up and down arrow buttons. Moreover, you can control the increments of the operations by changing the Increment value.


Figure 4.

Context Menu

Option Available for Description
Define Position Dummy Save the displayed position of the dummy by creating a New position or by overwriting an existing position.
Retrieve Position Dummy Position the dummy to its initial position or to another position by selecting this in the list of the saved positions.
Move Limbs Dummy Open the Entity Editor to define the position of the dummy using the automatic move to target functionality.
Positioning File Dummy Import or export a positioning file (*.daf) containing the position values of the dummy.
Pre-Simulation Dummy Export an input deck, for the appropriate solver, in order to simulate the deformation of the dummy.
Show Dummy and Bodies Displays the entity in the graphics area. The entities icon changes to bold indicating that the display state is on.
Hide Dummy and Bodies Turns off the entity in the graphics area. This selection affects each entities local display control, that is, will make the icon become ghosted indicating the display state is off.
Isolate Dummy and Bodies Displays only the selected entities, and turns off all other entities of the same type.
Review Dummy Display the dummy articulations and bodies in a simplified display mode.
Reset Review Dummy Resets the review of the previously selected entity.

Supported Entities

The Dummy () is the root of the hierarchy in the Dummy Browser. A dummy is defined by bodies () representing the different kinematic assemblies of the dummy.

Position Dummies

Position the Body Manually

  1. In the Dummy Browser, select a body.
  2. In the graphics area, click-and-drag the manipulator to interactively modify the position of the selected body.


    Figure 5.

Position the Body Automatically

  1. In the Dummy Browser, right-click on a body and select Move Limbs from the context menu.
    The Entity Editor opens.


    Figure 6.
  2. In the Multiple pairs field, select No (apply option to a single node) or Yes (apply option to a set of nodes and targets).
  3. If Multiple pairs is set to Yes, click Select pairs to open the Select multi nodes dialog and select nodes and target point pairs.
  4. Define a Node of a body.
  5. Define the Target location.
  6. Click Select Bodies to open the Dummy Bodies DOF dialog and select the bodies and degrees of freedom of the active bodies that will be able to move during automatic positioning.
    Select bodies by activating their corresponding checkbox, or picking them in the graphics area (right-click or left-click to activate/deactivate a body). Lock/unlock degrees of freedom by clicking the lock icon, or by picking the DOF arrows in the graphics area (right-click or left-click to activate/deactivate a DOF).


    Figure 7.
  7. Click Move to start the automatic positioning process.
  8. Click Save to save the achieved position.
    A name will be appended to the New position name field.

Setup Pre-Simulation

Export an input deck to simulate the deformation of the dummy.

Before you begin, Position Dummies.


Figure 8.

The simulation result files can be imported to update the initial FE model and thus remove the intersections and penetrations between the dummy components.

  1. In the Dummy Browser, right-click and on the dummy and select Pre-Simulation from the context menu.
  2. In the PreSimulation Tool dialog, define settings accordingly.
    1. In the PreSimulation type field, select a unit system.

      The unity system will automatically set the default simulation parameters to the correct unit. In any case, you can still modify these values manually.

    2. In the Reference Position field, select the Position that will define the starting position of the dummy in the pre-simulation.
      Per default, the Initial Position of the dummy is selected.
    3. In the Export File field, enter the pre-simulation deck name and directory.
      Per default, a deck with name “result” is exported into ~…/Local/Temp directory.
  3. Define PreSimulation Tool Options accordingly.
  4. Optional: Import the simulation result file to update the initial model, which allows the dummy node's coordinates to be updated and element initial stress state to be defined.
    • For LS-DYNA, click Import dynain File to find the .dynain file.
    • For Radioss, click Import h3d File to find the .h3d file.
  5. Click Export.

The pre-simulation deck is exported to the specified location.

During the export process of the dummy pre-simulation deck, HyperMesh exports the complete dummy model only, positioned in the selected Reference Position, per default, the Initial Position of the dummy.

The method used for the pre-simulation is known as the “cable” method, which uses 1D elements connected to dummy bodies, in order to pull them from their initial position to their final position.

All “cables” are automatically created on each dummy body and all boundary conditions needed for the pre-simulation.
Figure 9. Exported Dummy Pre-Simulation Model, with Cable Elements Attached to Dummy Bodies


The attachment nodes of the cables, nodes “N1; N2; N3” in the dummy assembly keyword are used, if they are defined.
Figure 10. Radioss



Figure 11. LS-DYNA
In case the nodes “N1; N2; N3” in the dummy assembly keyword are not defined, HyperMesh automatically detects the best three nodes to use on each body. In this case, you will receive a message.


Figure 12. Altair HyperMesh Message
After the simulation of the dummy positioning, the components are deformed and intersections between components are removed.


Figure 13.
The "cable" method guarantees a perfect final position matching with the final position defined in the Dummy Browser.


Figure 14.

PreSimulation Tool Options

Overview of supported options in the PreSimulation Tool.

LS-DYNA

Simulation Parameter
Simulation Time
Define the total simulation time in *CONTROL_TERMINATION for the pre-simulation.
Default value = 250ms.
Time Step
Define the control time step value in *CONTROL_TIMESTEP for the pre-simulation.
Default value = 0.001ms.
Force in cables
Define the pre-tension force to be applied on the cable elements in *MAT_CABLE_DISCRETE_BEAM.
Default value = 1.0 kN.
Force ramp up time
Define the ramp-up time for the pre-tension force in *MAT_CABLE_DISCRETE_BEAM.
Default value = 10.0ms.
Damping on cables
Define the damping value on the discrete elements in *MAT_DAMPER_VISCOUD.
Default value = 0.5.
Global damping value
Define the system damping constant in *DAMPING_GLOBAL.
Default value = 0.05.
Initial Stress Results
Import *INITIAL_STRESS_SOLID
Import the initial stresses for solid elements from the .dynain file.
Import *INITIAL_STRESS_SHELL
Import the initial stresses for shell elements from the .dynain file.
Import *INITIAL_STRESS_BEAM
Import the initial stresses for beam elements from the .dynain file.

Radioss

Simulation Parameters
Generate XREF for initial stresses
Create /XREF cards for the dummy components which are compatible with this RADIOSS feature in terms of material type and element formulation. The XREF cards are generated within the original session during the export of the pre-simulation deck, and not during import of .h3d file.
Simulation time
Define the total simulation time in /RUN card for the pre-simulation.
Default value = 250ms
Time Step
Define the control time step value in /DT/NODA/CST card for the pre-simulation.
Default value = 0.001ms.
Global damping value
Define the system damping constant in /DAMP card.
Default value = 0.05
Create rigids for end bodies
Automatically rigidify the end bodies (feet, hands, head) of the dummy during the pre-simulation.

Read Positioning Files

In the Dummy Browser, right-click on the dummy root name and select Positioning File > Import from the context menu.
Once the positioning file (*.daf) is read, the dummy will automatically be positioned according to the imported position data.