HM-4640: Dummy Position

In this step you will open HyperMesh along with the LS-DYNA user profile.

1. Start HyperMesh Desktop.
2. In the User Profile dialog, set the user profile to LS-DYNA, Keyword971_R8.0.

In this step you will open the model file, dummy_positioner.hm.

1. From the menu bar, click File > Open > Model.
2. In the Open Model dialog, navigate to your working directory and open the file, dummy_positioner.hm.

In this step you will position the dummy to its H-point location.

1. From the menu bar, click Tools > Dummy to open the Dummy Browser.
2. In the Dummy Browser, click on the THOR_FE dummy entity to activate the global positioning parameters in the Entity Editor.

   
   
   Figure 2.

3. In the Entity Editor, for the Global rotation attribute Rx, type 180.
   The dummy rotates.
4. Under H-Point location, click on the coordinates area and then click .

   
   
   Figure 3.

5. In the graphics area, select the node tagged as H-Point Location on the seat.

   
   
   Figure 4.

6. In the panel area, click proceed.
   The dummy automatically moves to the selected H-Point location.

   
   
   Figure 5.

In this step you will manually position the dummy limbs.

1. In the Dummy Browser, click the lower_leg_left body entity.
   The joint manipulator appears in the graphic area and the Entity Editor opens.

   
   
   Figure 6.

2. In the graphics area, select the smallest blue arc on the manipulator to interactively manipulate the selected body.
3. Position the lower leg in the following ways:
   • In the graphics area, select the smallest blue arc on the manipulator to interactively position the lower leg to an angle value of -70°.
   • In the Entity Editor Current angle field, type -70.
4. Repeat this operation to position the lower_leg_right body entity.

In this step, you will automatically position the hands.

1. In the Dummy Browser, right-click on the THOR_FE dummy entity and select Move Limbs from the context menu.
2. In the Entity Editor, set Multiple pairs to Yes.
3. Click on Select pairs field.
4. Position the left hand:
   1. In the Select multi nodes dialog, Source Point column, click on the first cell.
   2. Click the Nodes selector.
   3. In the panel area, click the node selector and type 420848 in the id= field.
   4. Click proceed.
   5. In the Select multi nodes dialog, Target Point field, click the first cell.
   6. Click .
   7. In the graphics area, select the node tagged as Left Hand Target.
   8. In the panel area, click proceed.
5. Position the right hand by repeating step 4.
   1. In the Select multi nodes dialog, click to add a second row to define the Source Point and Target Point for the right hand.
   2. For Source Point, select the node with id 320848.
   3. For Target Point, select the node tagged as Right Hand Target.
6. In the Select multi nodes dialog, click Close.
7. In the Entity Editor, click Select Bodies.
8. In the Dummy Bodies DOF dialog, enable/disable dummy bodies and body DOFs to be taken into account for the automatic positioning of the dummy limbs:
   1. Deselect the bodies upper_torso and head_neck by clearing their corresponding checkboxes in the Body column.

      You can also deselect a body by right-clicking on the desired body in the graphics area. Activate a body or a DOF by left-clicking on the desired body or joint arrow in the graphic area.

   2. Click OK to close the dialog.
9. In the Entity Editor, click Move to activate automatic limbs positioning.

   
   
   Figure 7.

In this step, you will save and retrieve dummy positions.

1. In the Dummy Browser, right-click on the THOR_FE dummy entity and select Define Position > New from the context menu.
2. In the Update Position info dialog, type Final Position in the Name field and click Close.
   The actual position of the dummy is saved and can be retrieved for future reference.
3. To retrieve the initial dummy position, in the Dummy Browser, right-click on the THOR_FE dummy entity and select Retrieve Position > Initial Position from the context menu.
   The position of the dummy automatically moves to its initial position.
4. To retrieve the saved dummy position, in the Dummy Browser, right-click on the THOR_FE dummy entity and select Retrieve Position > Other Position.
5. In the Positions dialog, select Final Position and click Close.

In this step you will link a dummy to a seat mechanism.

1. Open the Mechanism Browser from the menu bar by clicking Tools > Mechanism.
2. In the Mechanism Browser, expand the Driver Seat mechanism to observe the different joints and bodies defined.

   
   
   Figure 8.

3. Right-click on the Driver_Seat mechanism entity and select Link To Dummy from the context menu.
4. In the Dummies dialog, select THOR_FE and click Next.
5. In the Mechanism Bodies [Master Body] dialog, select Seat_Cushion and click Next.
6. In the Dummy Bodies [Child Bodies] dialog the body containing the H-Point of the dummy is automatically selected, and the Body’s DOF linked with the master body are automatically set-up to TX; TY; TZ, which is sufficient. Click Close to finalize the linking of the dummy to the seat mechanism.
   At this point, any motion of the seat will result in an according global motion of the dummy. It is also possible to constrain some bodies of the dummy that may remain in position, such as the feet.
7. Create constraints on bodies by right-clicking on the Driver_Seat mechanism and selecting Create > Constraint > Point Node from the context menu.
8. In the Entity Editor, Body field, click <Unspecified> >> Body.
9. In the Select Body dialog, select ankle_left2 and click OK.
10. In the Entity Editor, Point node field, click <Unspecified> >> Node.
11. In the panel area, click the node selector and type 681450 in the id= field.
12. Click proceed.
13. In Entity Editor, click the Fixed DOF field and select the first four checkboxes and the last checkbox. Leave the fifth checkbox cleared. Like this, the three translations and the rotations RX and RZ of the selected body are fixed in the global coordinate system. RY is free.

    
    
    Figure 9.

14. Create a constraint on the ankle_right2 body and node id 581450 with the same fixed DOF.

    
    
    Figure 10.

15. In the Mechanism Browser, right-click on the Fix_RailToMove_Rail joint and select Move from the context menu.
16. In the Entity Editor, Current Distance field, type -50.0.
    Note how the dummy moves with the seat and how the position of the legs and feet are updated because of the constraints defined on the feet.

    
    
    Figure 11.