RD-T: 3150 Seat Model with Dummy

This tutorial presents the different steps involved in building a simple Sled model using HyperCrash pre-processing tool.

Model Files

Before you begin, copy the file(s) used in this tutorial to your working directory.

Start HyperCrash

  1. Open HyperCrash.
  2. Set the User profile to RadiossV2023 and the Unit system to N_mm_s_T.
  3. Set User Interface style as New.
  4. Set your working directory to where the downloaded file is located.
  5. Click Run.
  6. Click File > Import > Radioss.
  7. In the input window, select SEAT__00D00.rad.
  8. Click OK.

Merge Models

  1. Click File > Import > Radioss.

    rd3150_hc_import
    Figure 1.
    A HyperCrash message window prompt appears.
  2. Click Merge.
  3. Select the file FLOORD00.rad.
  4. Click OK.
  5. In the Set all to field, enter the value 100000.
  6. Click the Set all to button to offset the numbering of all the entities.

    rd3150_merge
    Figure 2.
  7. Click Merge to merge the floor model.
  8. Redo the steps 1 to 7 for the cushion model:
    File:
    • FOAMD00.rad
    • Set all to offset: 200000
  9. Redo the steps 1 to 7 for the seatbelt model:
    File:
    • BELTD00.rad
    • Set all to offset: 300000

Set Model Hierarchy

  1. Click the Tree tab and select the subset of the seat named Seat model (300005).
  2. Right-click and select Change Name.

    rd3150_changename_11
    Figure 3.
  3. In the Change Name window, enter the name Seatbelt.
  4. Click Ok.
  5. Click any item on the tree, right-click and select New Assembly.
  6. Enter the name Frame and click Ok.
  7. Select the parts Seat plate, Backseat plate, Feet, Seat frame, and Backseat frame using the Shift or Ctrl keys.
  8. Press and hold the middle mouse button and drag the selected parts into the new assembly Frame.
  9. Select the Tree root (Seat) and right-click.
  10. In the pop-up menu, select List Selection.

    rd3150_selectionlist
    Figure 4.
    The List Selection dialog opens.
  11. In the displayed window, check if all parts have properties (PID) and materials (MID).
  12. Click Close > Export the model to save.

Connect Models

To add the feet of the seat and the seatbelt anchorage point to the floor rigid body:
  1. Click Mesh Editing > Rigid Body.

    rd3150_connections
    Figure 5.
  2. Select the rigid body: Floor.
  3. Click See selected rigid bodies (reviewgeneral-24).
  4. Click Display All07_display and then Left View (F11).
  5. Right-click in the Grnod_Id entry box and click Select in graphic, click selectbyboxadd-24Add nodes by box selection and select all the nodes of the seat, feet and the anchorage points of the seatbelt.
  6. Right-click to validate.
  7. Select the Floor rigid body in the list, right-click and add the rigid body and main node to time history.

    rd3150_data_history
    Figure 6.

Connect Seat Cushion to Seat Frame

  1. Click LoadCase > Contact Interface.
  2. Right-click in the window and select Create New > Kinematic condition (Type 2).
  3. Display only the cushion parts. Press F11 for XZ view, select Secondary nodes section, and click selectbyboxadd-24 Add noes by box selection.
  4. Holding down the Shift key, click to draw a polygon window around nodes on the backside of cushion of the nodes.
    Tip: Press the letter P for non-perspective view, if needed.

    Press Shift and draw a closed polygon window around the nodes to select. When finished, release the Shift key.

  5. Display Frame Assembly in the Tree, pick Main surface section, click arrow_upAdd/Remove a face and pick one element on each part of the frame facing the cushion. Then select the Expand option on the lower right corner to pick select all.
  6. Select the Expand option on the lower right corner to select all the elements of the seat assembly facing the seat cushions.
  7. Click Yes or Enter on the keyboard to end the selection.

    rd3150_contact_seats
    Figure 7.
  8. For the Title of the contact, enter seat cushion fixation.
  9. Click Save.
  10. Click icon_show_hide_checks at the top of the interface panel, to check the interface.

    rd3150_contact_tab
    Figure 8.
    The created interface should be displayed with green text. Otherwise, the interface has to be modified.
  11. Click Close.
  12. Click Export to save the model.

Position the Dummy

  1. Click Safety > Dummy Positioner.

    rd3150_safety_dp
    Figure 9.
  2. From the Dummy model list menu, select New dummy.

    rd3150_newdummy
    Figure 10.
    A DummyMng panel opens.
  3. Select the File subpanel.
  4. Select the file H350R12BD00.

    rd3150_safety_dummymgr
    Figure 11.
    The dummy model is displayed in the small graphic window.
  5. Click Validate.
  6. Set Set all to value to 400000.
  7. Click the Set all to button to offset the numbering of all entities.
  8. Click OK to merge the Dummy model.
  9. Click Import in the dummy positioning window and select the file H350R12B_Position.M00 and click OK.
    H350R12B_Position.M00 contains all parameters for the automatic dummy positioning.

    rd3150_safety_dp2
    Figure 12.
  10. Close the Dummy positioner and click Export to save the model.

Add the Seatbelt

  1. Click Safety > Belt Generator.
  2. Enter the name Upper belt and click OK to validate.

    rd3150_belt_generator
    Figure 13.
  3. Click Seat belt reference points (selectseatbeltnodes-35).
  4. Click Add nodes by picking (selectnodegeneral-24) and select three nodes, as shown in the following image (red dots).

    rd3150_belt_generator2
    Figure 14.
  5. Click Yes on the right corner and OK to validate the node selection.
  6. Click Add/Remove body parts (selectpartgeneral-24) and select the parts: torso, pelvis, upper legs, and the seat cushion fabric, as shown in red in the image.

    rd3150_dummy_add-remove
    Figure 15.
  7. Click Yes to validate the selection.
  8. Set the Gap value to 5.00 mm.
  9. Set the Belt geometric width to 40.
  10. Set the Element Size to 8.
  11. Click Material (databaseimport-12) and select the material file BELT.mat you saved to your working directory.
  12. Click OK.
  13. Click Property (databaseimport-12) and select the property file BELT.prop you saved to your working directory.
  14. Click OK.
  15. Click Preview to display the proposed seat belt. Some intersections may exist between the seat cushion and the seat belt.
  16. Use the orientation tools to modify the angle of the Rigid Body 2.

    rd3150_orientation_tools
    Figure 16.

    rd3150_orientation_model
    Figure 17.
  17. Click Save to save the belt definition.
  18. Redo the same operations in order to create the lower belt. Select nodes, as shown below.

    rd3150_belt_lower
    Figure 18.
  19. Select the parts: pelvis, upper legs and seat cushion fabric.
  20. Click Preview > Save > Close.

    rd3150_belt_pelvis
    Figure 19.
  21. Click Export to save the model.

Seatbelt versus Dummy

Create Contact Interfaces

During the seatbelt creation, two contact interfaces between the seatbelt and the dummy have been created. You will need to check and remove any remaining intersections and penetrations.

  1. Click LoadCase > Contact Interface.
  2. Select interface BELT ID 400038.
  3. Click See selected (reviewgeneral-24) to display.
  4. Click in Main Surface, right-click in the modeling window, and click selectpartgeneral-24 Include picked parts to select the Fabric backframe and the Backseat frame as they may come into contact with the shoulder belt during the analysis.

    rd3150_seatbeltvsdummy
    Figure 20.
  5. Click Save.
  6. Select interfaces BELT ID 400038 and BELT ID 400039.
  7. Click See selected (reviewgeneral-24) to display.
  8. Set Coulomb friction to 0.3.
  9. Set Friction penalty formulation to 2.
  10. Click Save.
  11. Select interfaces BELT ID 400038 and BELT ID 400039.
  12. Click Check penetration selected interfaces (checkpenetration-24).
  13. In the Quality panel, remove the intersections and penetrations using the Depenetrate Auto (depenetrateauto).
  14. Click Close in order to come back to the Contact Interface panel.
  15. Click Export to save the model.

Create Seat Structure

Creation of Self-Impact between different parts of the Seat.

  1. In the Tree window, select subsets Frame, Floor and Foam.
  2. Click the Isolate icon 06_view.

    rd3150_seat_structure
    Figure 21.
  3. Right-click in the Contact list and select Create New Multi-usage (Type 7).
  4. Click Self impact.
  5. Set the Title to Self impact seat structure.
  6. Set Gap/element option to Variable gap.
  7. Set Coulomb friction to 0.2.
  8. Set Friction penalty formulation to 2.
  9. Right-click in the Main Surface entry box and click Select in graphics > Add selected parts of tree (treeaddentity-24).
  10. Click Save.
  11. Select the self impact seat structure interface in the list.
  12. Click Check penetration selected interfaces (checkpenetration-24). Some penetrations exist between the seat cushion and the seat structure.
  13. Switch to the Tree window, and select the subset named Frame.
  14. Switch to the Quality window and click Fixed part (selectpartgeneral-24).
  15. Press the Esc key to remove all selected parts.
  16. Click Add selected parts of tree (treeaddentity-24).
  17. Click Depenetrate Auto (depenetrateauto).
    Note: Only the nodes of the seat cushion are moved. The seat parts are fixed.
  18. Click Close twice.
  19. Click Export to save the model.

Create the Interface between Dummy Feet and Floor

Creation of an interface between dummy feet and the floor.

  1. Right-click in the Contact list and select Create New > Tied with void (Type 10).
  2. Set the dummy feet as secondary nodes.
  3. Set the floor as main surface.

    rd3150_contact_seat-floor
    Figure 22.
  4. Set the interface Title to Feet - Floor.
  5. Set Gap for impact activation to 3.0 mm.
  6. Click Save > Close.
  7. Click Export to save the model.

Modify Seat Cushion Mesh

Modifying the seat cushion mesh to conform to the dummy using the Seat Deformer tool.

Edit the Pre-simulation Settings

To remove the intersection between the dummy and the set, HyperCrash will generate a Radioss input deck and run a pre-simulation step. The settings for the pre-simulation are defined in the menu Option > Presimulation Parameters (for Seat Deformer). For this exercise, modify the settings, as shown below:

rd3150_presimulation
Figure 23.

Select the Seat Parts

  1. Click the Tree tab and select Foams assembly, Seat plate, Backseat plate, Seat frame, and Backseat frame, as shown below.

    rd3150_selecting_parts
    Figure 24.
  2. Click Safety > Seat Deformer > Pre-simulation (new) and click Add selected parts of Tree (treeaddentity-24).

    rd3150_seat_deformer
    Figure 25.

Review the Results and Apply the Deformed Shape

  1. Once the pre-simulation is completed, review the results in by opening the .h3d file. Create a cut section in the middle of the dummy and verify that the dummy does not intersect/penetrate the seat foam.

    rd3150_presimulation_results
    Figure 26.
  2. If an intersection/penetration does not exist, go back to the window and load the results by clicking Yes in the dialog.
  3. When the job is completed, click Yes to load the results.
    You can also load the results by clicking File > Import > h3d node coordinates, then click Yes to the message Warning: all the nodes coordinates will be replaced by the ones found in the selected .h3d file.

    rd3150_presimulation_results2
    Figure 27.
    Below is the deformed shape for the seat foam after the pre-simulation.

    rd3150_seat_deformed
    Figure 28.

Check Initial Penetration between Seat and Dummy

After the seat deformation, check if any initial penetrations remain between the seat and the dummy.
  1. Click LoadCase > Contact Interface to open the Contact Interface tab.
  2. Select interface Dummy - Seat.
  3. Click Check penetration selected interfaces (checkpenetration-24). Penetrations exist between the seat beam and the dummy.
  4. Click Select All (treeselectunselectall-24).
  5. Click Highlight by Vector (higlightvector).

    rd3150_dummy_highlight.png
    Figure 29.
  6. Click Fixed part (selectpartgeneral-24) .
  7. Press the Esc key to remove all selected parts.
  8. Click Fixed part (selectpartgeneral-24) and then select the displayed parts of the dummy.
  9. Click Depenetrate Auto (depenetrateauto).
    Only the nodes of the seat cushion are moved. The parts of the dummy are fixed.
  10. Click Close.
  11. Click Export to save the model.

Loadcase Setting

Update Initial Velocity

Update the initial velocity defined in the model to include all the nodes in the model.

  1. Click LoadCase > Initial Velocity to open the Initial Velocity tab.
  2. Select the initial velocity All in the list.
  3. Click See selected initial velocity (reviewgeneral-24).
  4. Right-click in the Support entry box and click Select in graphics > Add all nodes (10_addallnodes).
  5. Change [Vx] X Velocity from -10000 to -13000 mm/s.

    rd3150_initial_vel
    Figure 30.
  6. Click Save > Close.
  7. Click Export to save the model.

Update Imposed Velocity

Update the imposed velocity on the floor to decelerate the car.

  1. Click LoadCase > Imposed > Imposed Velocity.
  2. Select Imposed velocity in the list.
  3. Click See selected imposed velocity (reviewgeneral-24).
    The floor rigid body is displayed on the screen. The imposed velocity is defined on its main node.

    rd3150_imposed_vel_modify
    Figure 31.
  4. Right-click the Time Function entry box and select Edit function. Check if the initial value of the function is the same as the initial velocity.

    rd3150_funct_window
    Figure 32.
  5. Click Save > Close.
  6. Click Export to save the model.

Set Boundary Conditions

To simulate the Sled Test, you need to constrain all degrees of freedom on the floor except X-direction.

  1. Click LoadCase > Boundary Condition.
  2. Select Floor in the list.
  3. Click See selected boundary condition (reviewgeneral-24).
    The floor rigid body is displayed on the screen. The boundary condition is defined on its main node.
  4. Verify that the degree of freedom for Ty, Tz, Rx, Ry, and Rz are fixed.

    rd3150_floor
    Figure 33.
  5. Click Save > Close.
  6. Click Export to save the model.

Set Time History Data

Select Nodes

  1. Click Data History > Time History.
  2. Select the node group H350MEF2D00_th_nodes.
  3. Click See selected th (reviewgeneral-24). These are the nodes of the dummy rigid bodies.
  4. For the first 5 nodes of the group:
    1. Select the node in the list.
    2. Click See selected node (reviewgeneral-24).
    3. Enter a name in the field Node name, as shown in the table.
    4. Click Ok.

    rd3150_time_history
    Figure 34.
  5. When all labels are defined, click Save > Close.
  6. Click Export to save the model.

Select Parts

  1. Click Data History > Time History.
  2. Select the second and third part group on the list.

    rd3150_dh_deletepart
    Figure 35.
  3. Click Delete selected th (deletegeneral-24).
  4. Click Yes to the question in the main window.
    The selected parts groups are deleted from the model.
  5. Select the remaining part group in the list.
  6. Click See selected th (reviewgeneral-24).
  7. Click the Tree tab and select the root of the tree.

    rd3150_tree_root
    Figure 36.
  8. Switch back to the Data History panel and click Add parts by tree selection.

    rd3150_dh_add
    Figure 37.
  9. Click Save.
  10. Click Export to save the model.

Add Interfaces

Add all interfaces to Time History.
  1. Click LoadCase > Contact Interface to open the Contact Interface tab.
  2. Select all interfaces in the list.
  3. Right-click and select Data History > Yes.

    rd3150_contact_thadd
    Figure 38.

Clean the Model

  1. Go to Quality Module.
  2. Select Check All Solver Contact Interfaces.
  3. Make sure there are no intersections and initial penetrations; if so, fix them.
  4. Click Close.
  5. Go to Mesh Editing and clean so that all the unused materials and properties are removed.

Create Control Cards and Export Model

  1. Click Model > Control Cards to create the Control Cards in the images below.
    Note: The /DT/SHELL/DEL command is used to delete some of the rigid body shells to allow the dummy’s joints to bend during the simulation.

    rd3150_control_cards1
    Figure 39.

    rd3150_control_cards2
    Figure 40.

    rd3150_control_cards3
    Figure 41.

    rd3150_control_cards4
    Figure 42.
  2. Click File > Export > Radioss.

    rd3150_export_rad
    Figure 43.
  3. Enter a name for the model in the file output window and click OK.

    rd3150_export_dialog
    Figure 44.
  4. Write relevant information regarding your model in the Header window.
  5. Click Save Model.
    The model is now ready to be computed.