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 Law 37 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.

Exercise

Step 1: Load the RADIOSS (Block) User Profile

1.	Launch HyperMesh Desktop.

2.	From the Preferences menu, select the User Profiles or click the icon in toolbar.

3.	Select RADIOSS (Block140) and click OK.

Step 2: Load the boat_ditching_2.hm file

1.	From the toolbar, click the Open Model icon to open the boat_ditching_2.hm file you saved to your working directory from the radioss.zip file. Refer to Accessing the Model Files.

2.	Click Open. The model loads into the graphics area.

Step 3: Define and assign Material, Property to component AIR

1.	In the Model browser, right-click and select Create > Material. The new material shows in the Entity Editor.

2.	For Name, enter air.

3.	For Card Image, select M37_BIPHAS and click Yes to confirm.

4.	Input the values, as shown below.

Remember to select ALE under ALE CFD Formulation.

rd3580_biphas_14

5.	In the Model browser, create a new property named Air with a Card Image of P14_SOLID.

6.	Click on the component Air and assign as the Prop_Id and air as the Mat_Id in the Entity Editor.

Step 4: Define and assign Material, Property to component WATER

1.	In the Model browser, right-click and select Create > Material. The new material shows in the Entity Editor.

2.	For Name, enter water.

3.	For Card Image, select M37_BIPHAS.

4.	Input the values, as shown below:

Remember to select ALE under ALE CFD Formulation.

rd3580_biphas_water_14

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.

Step 5: Define and assign Material, Property to component BOAT

1.	In the Model browser, right-click and select Create > Material. The new material shows in the Entity Editor.

2.	For Name, enter boat.

3.	For Card Image, select M1_ELAST.

4.	Input the values, as below.

rd3580_boat_13

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

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

Step 6: Define an Interface between Boat and Fluid

1.	Click Tools > Create Cards > ALE-CFD-SPH > INTER_TYPE18. The new interface opens in the Entity Editor.

2.	For Name, enter Boat-Fluid.

3.	Enter the parameter values, as shown below for Stfval and GAP.

rd3580_boat-fluid_14

3.	Set the Surf_id (M) for the master selection to Components and select the boat component.

4.	Set the Grnod_id (S) for the slave selection to Components and select all the components, except boat.

Step 7: Create RBODY for the Boat and assign mass to the Master Node

1.	In the Model browser, isolate the boat part.

2.	From the pull-down menu, select Tools > Rbody Manager.

3.	For Title, enter RIGID_BOAT. Verify that the Master node is set to Calculate Node and set the Slave node(s) to Parts and select the Boat.

rd3580_rbody_mgr_10SA1

4.	Click Create to create the RBODY. The created RBODY appears in the table.

5.	Select the created RBODY in the table and click Edit Card 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.

Step 8: Create Initial Velocity

1.	Click BCs Manager in the Utility panel or 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 (ID: 690501).

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

Step 9: Create Boundary Conditions on outermost faces

1.	In the Model browser, right-click on the Components subfolder 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 figure.

rd3580_bc_10SA1

rd3580_bc2_10SA1

7.	Check Tx box to constraint translation in X direction.

8.	Click Create to create the constraint.

9.	Follow the same procedure (step 1-8) but create constraint in Y direction on the sides parallel to Y plane of global axis.

10.	Follow the same procedure (step 1-8) but create constraint in Z direction on the sides parallel to Z plane of global axis.

Step 10: Creating control cards and output requests

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	Tmin	0.0

Step 11: Export the model

1.	Click File > Export or click the Export icon .

2.	For File:, 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.	Click Merge starter and engine file to export the one solver deck (or export separately).

6.	Click Export to export solver deck.

Step 12: Run the solver using RADIOSS Manager

1.	Go to Start > Programs > Altair HyperWorks 14.0 > RADIOSS.

2.	For Input file, browse to the exercise folder and select the file boatditching_2_0000.rad.

rd3580_radioss_mgr2

Step 13 (Optional): View the results in HyperView

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