Boat Ditching with Boundary Elements

The objective of this tutorial is to simulate Boat Ditching with Boundary Elements to represent continuous water using bi-phase material law (Law 37). In this model, the top chamber is air, lower chamber is water surrounded by boundary elements. Law 37 is used for air, water and boundary. 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_1.hm file

1.	From the toolbar, click the Open Model icon to open the boat_ditching_1.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 up in the Entity Editor (EE).

2.	For Name, enter air.

3.	For Card Image, select M37_BIPHAS.

4.	Input the values, as shown below.

Remember to select ALE under ALE CFD Formulation.

rd3580_air_14

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.

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 up in the Entity Editor (EE).

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_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 up in the Entity Editor (EE).

2.	For Name, enter boat.

3.	For Card Image, select M1_ELAST.

4.	Input the values, as shown below:

rd3580_boatA_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 and assign Material, Property to component Air-BC

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-bc.

3.	For Card Image, select M37_BIPHAS.

4.	Input the values, as shown below.

Remember to select ALE under ALE CFD Formulation.

rd3580_air-bc_14

5.	Click on the component Air-BC and assign Air as the Prop_Id and air-bc as the Mat_Id in the Entity Editor.

Step 7: Define and assign Material, Property to component Water-BC

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-bc.

3.	For Card Image, select M37_BIPHAS.

4.	Input the values, as shown below.

Remember to select ALE under ALE CFD Formulation.

rd3580_water-bc_14

5.	Click on the component Water-BC and assign Water as the Prop_Id and water-bc as the Mat_Id in the Entity Editor.

Step 8: 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-fluidA_14

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.

Step 9: Create RBODY for the Boat and assign mass to the Master Node

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 and set 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 right-click and select 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 10: Create 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

Step 11: Create Boundary Conditions on outermost faces

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 tab and select a node on both faces normal to x-axis.

6.	Then click the nodes yellow tab 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 12: 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-1
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-1
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/ELEM	Status	[Checked]
ENGINE KEYWORDS	ANIM/ELEM	VONM	[Checked]
ENGINE KEYWORDS	ANIM/ELEM	DENS	[Checked]
ENGINE KEYWORDS	ANIM/ELEM	PRES	[Checked]
ENGINE KEYWORDS	ANIM/VECT	Status	[Checked]
ENGINE KEYWORDS	ANIM/VECT	VEL	[Checked]
ENGINE KEYWORDS	ANIM/VECT	CONT	[Checked]
ENGINE KEYWORDS	ANIM/DT	Status	[Checked]
ENGINE KEYWORDS	ANIM/DT	Tstart	0
ENGINE KEYWORDS	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 13: 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_1 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 one solver deck (or export separately).

6.	Click Export to export solver deck.

Step 14: 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_1_0000.rad.

rd3580_boatditching1_14

Step 15 (Optional): View the results in HyperView

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