Boat Ditching without Boundary Elements

The objective of this tutorial is to simulate Boat Ditching without Boundary Elements. So there is no boundary to represent continuous water. Basically, you are simulating Boat-Ditching in an enclosed volume.

In this model, the top chamber is air (including its outer layer) and the lower chamber is water (including its outer layer). Bi-Phase material LAW37 was used to model air and water. Boundary conditions are applied on each surface of boundary in the normal direction. An interface between fluid and boat (CEL) is defined to manage the contact.

Load the Radioss User Profile

  1. Launch HyperWorks Desktop.
  2. From the Preferences menu, select User Profiles or click the userProfile-24 icon in toolbar.
  3. Select Radioss (Block140) and click OK.

Open the Model File

  1. Click the Open Model icon fileOpenModel-24 to open the boat_ditching_2.hm file you saved to your working directory from the radioss.zip file.
  2. Click Open.
    The model loads into the modeling window.

Create and Assign a Material and Property to Air

  1. In the Model Browser, right-click and select Create > Material.
    The new material shows up in the Entity Editor.
  2. For Name, enter air.
  3. For Card Image, select M37_BIPHAS.
  4. Input the values, as shown below.

    rd3580_air_14
    Figure 1.
    Note: Remember to select ALE under ALE CFD Formulation.
  5. Create a new property named Air with a Card Image of P14_SOLID by right-clicking in the Model Browser.
  6. Click on the component Air and assign Air as the Prop_Id and air as the Mat_Id in the Entity Editor.

Create and Assign a Material and Property to Water

  1. In the Model Browser, right-click and select Create > Material.
    The new material shows up in the Entity Editor.
  2. For Name, enter water.
  3. For Card Image, select M37_BIPHAS.
  4. Input the values, as shown below.

    rd3580_water_14
    Figure 2.
    Note: Remember to select ALE under ALE CFD Formulation.
  5. In the Model Browser, create a new property named Water with a Card Image of P14_SOLID.
  6. Click on the component Water and assign Water as the Prop_Id and water as the Mat_Id in the Entity Editor.

Create and Assign a Material and Property to Boat

  1. In the Model Browser, right-click and select Create > Material.
    The new material shows up in the Entity Editor.
  2. For Name, enter boat.
  3. For Card Image, select M1_ELAST.
  4. Input the values, as shown below:

    rd3580_boatA_13
    Figure 3.
  5. In the Model Browser, create a new property named Boat with a Card Image of P1_SHELL and assign the new property with the values shown below:

    rd3580_boat_pshell_14
    Figure 4.
  6. Click on the component Boat and assign Boat as the Prop_Id and boat as the Mat_Id in the Entity Editor.

Define an Interface between Boat and Water

  1. Click Tools > Create > Cards > ALE-CFD-SPH > INTER_TYPE18.
    The new interface shows up in the Entity Editor.
  2. For Name, enter Boat-Fluid.
  3. Enter the parameter values, as shown below for Stfval and GAP.


    Figure 5.
  4. Set the Surf_id (M) for master selection to Components and select the boat component.
  5. Set the Grnod_id (S) for slave selection to Components and select all the components, except boat.

Create an RBODY for the Boat and Assigning Mass

  1. Isolate the boat part using the Model Browser.
  2. From the pull-down menu, select Tools > Rbody Manager.
  3. For Title, enter RIGID-BOAT, verify that Master node is set to Calculate Node, set Slave node(s) to Parts, and select the Boat.

    rd3580_rbody_mgr_10SA1
    Figure 6.
  4. Click Create to create the RBODY.
    The created RBODY appears in the table.
  5. Select the created RBODY in the table and right-click and select Edit card card_editor to open the Card Image panel.
  6. Assign a mass of 23.04 kg to the boat.
  7. Click return to return from the Card Image panel.
  8. Click Close to close the RBODY Manager.

Create an Initial Velocity

  1. Click Tools > BCs Manager.
  2. For Name, enter Boat.
  3. For Select type, select Initial Velocity.
  4. Set GRNOD to Nodes.
  5. Click the Node tab and select the master node of the RBODY created in the previous step.
  6. Set Z velocity (VZ) to -11.0 indicating velocity opposite to global Z-axis.
  7. Click Create to create the initial velocity boundary condition.

    rd3580_boat_10SA1
    Figure 7.

Create the Boundary Conditions

  1. In the Model Browser, right-click on the Components sub-folder and select Show to display all components.
  2. Enter a new boundary condition in the BCs Manager named Constraint-x.
  3. For Select type, select Boundary condition.
  4. Set GRNOD to Nodes.
  5. Click the Node selector and select a node on both faces normal to x-axis.
  6. Click the nodes selector and select By face.
    HyperMesh will automatically select nodes on the face, as shown in the figures.

    rd3580_bc_10SA1
    Figure 8.

    rd3580_bc2_10SA1
    Figure 9.
  7. Check Tx to constraint translation in X direction.
  8. Click Create to create the constraint.
  9. Follow the same procedure to create a constraint in Y direction on the sides parallel to Y plane of global axis.
  10. Follow the same procedure to create a constraint in Z direction on the sides parallel to Z plane of global axis.

Create Output Request and Control Cards

  1. Launch the HyperMesh Solver Browser from View > Browsers > HyperMesh > Solver.
  2. Right-click in the Solver Browser general area to create the cards, shown below with the given values for each parameter:
    Keyword Type Keyword Parameter Parameter Value
    CONTROL CARDS TITLE Status [Checked]
    CONTROL CARDS TITLE TITLE Boat-Ditch-2
    CONTROL CARDS MEMORY Status [Checked]
    CONTROL CARDS MEMORY NMOTS 40000
    CONTROL CARDS SPMD Status [Checked]
    CONTROL CARDS IOFLAG Status [Checked]
    CONTROL CARDS ANALY Status [Checked]
    ALE-CFD-SPH ALE_CFD_SPH_CARD Status [Checked]
    ALE-CFD-SPH ALE_CFD_SPH_CARD ALE_Grid_Velocity [Checked]
    ENGINE KEYWORDS RUN Status [Checked]
    ENGINE KEYWORDS RUN RunName Boat-Ditch-2
    ENGINE KEYWORDS RUN Tstop 30.01
    ENGINE KEYWORDS PARITH Status [Checked]
    ENGINE KEYWORDS PARITH Keyword2 OFF
    ENGINE KEYWORDS PRINT Status [Checked]
    ENGINE KEYWORDS PRINT N_Print -1000
    ENGINE KEYWORDS ANIM > ANIM/ELEM Status [Checked]
    ENGINE KEYWORDS ANIM > ANIM/ELEM VONM [Checked]
    ENGINE KEYWORDS ANIM > ANIM/ELEM DENS [Checked]
    ENGINE KEYWORDS ANIM > ANIM/ELEM PRES [Checked]
    ENGINE KEYWORDS ANIM > ANIM/VECT Status [Checked]
    ENGINE KEYWORDS ANIM > ANIM/VECT VEL [Checked]
    ENGINE KEYWORDS ANIM > ANIM/VECT CONT [Checked]
    ENGINE KEYWORDS ANIM > ANIM/DT Status [Checked]
    ENGINE KEYWORDS ANIM > ANIM/DT Tstart 0
    ENGINE KEYWORDS ANIM > ANIM/DT Tfreq 1.0
    ENGINE KEYWORDS DT > DT Status [Checked]
    ENGINE KEYWORDS DT > DT Tscale 0.5
    ENGINE KEYWORDS DT > DT Status 0.0

Export the Model

  1. Click File > Export or click the Export icon .
  2. Click the folder icon and navigate to the destination directory where you want to export to.
  3. For Name, enter boatditching_2 and click Save.
  4. Click the downward-pointing arrows next to Export options to expand the panel.
  5. Select Merge starter and engine file to export both the Starter and Engine file in one file.
  6. Click Export to export the file.

Run the Model in the Solver

  1. Go to Start > Programs > HyperWorks 2019 > Radioss.
  2. For Input file, browse to the exercise folder and select the file boatditching_2_0000.rad.
  3. Click Run.

Review the Results

The exercise is complete. Save your work to a HyperMesh file.