RD-3530: Buckling of a Tube using Half Tube Mesh

This exercise simulates buckling of a tube using half tube mesh with symmetric boundary conditions.

The figure illustrates the structural model used for this tutorial: a half tube with a rectangular section (38.1 x 25.4 mm) and length of 203 mm.

rd3530_boxtube

Model Description

•	UNITS: Length (mm), Time (ms), Mass (kg), Force (kN) and Stress (GPa)

•	Simulation time: Engine [0 – 10 ms]

•	The tube thickness is 0.914 mm.

•	An imposed velocity of 13.3 mm/ms (~30 MPH) is applied to the right end of the tube

•	Elasto-plastic material using Johnson-Cook law /MAT/PLAS_JOHNS (STEEL).

[Rho_Initial] Initial density = 7.85e-6 Kg/mm3

[E] Young’s modulus = 210 GPa

[nu] Poisson coefficient = 0.33

[a] Yield Stress = 0.206 GPa

[b] Hardening Parameter = 0.450 GPa

[n] Hardening Exponent = 0.5

[SIG_max] Maximum Stress = 0.0 GPa

File needed to complete this tutorial: tube_box.hm

Exercise

Step 1: Load the RADIOSS User Profile

1.	Launch HyperMesh Desktop.

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

3.	Select RADIOSS (Block140) and click OK.

Step 2: Load the model

1.	From the toolbar, click the Open Model icon to open the tube_box.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: Create Material for the tube

1.	In the Model browser, right-click and select Create > Material. The Entity Editor is displayed below the Model browser.

2.	For Name, enter Steel.

3.	Set Card Image to M2_PLAS_JOHNS_ZERIL and click Yes to confirm.

4.	Set Type as PLAS_JOHNS.

5.	Input the values, as shown below:

rd3530_steel_13

6.	Click anywhere in the Model browser to exit the Entity Editor.

Step 4: Create Property for the tube

1.	In the Model browser, right-click and select Create > Property. The Entity Editor is displayed below the Model browser.

2.	For Name, enter Pshell.

3.	Set Card Image to P1_SHELL.

4.	Input the values, as shown below:

rd3530_pshell_13

Step 5: Assign material and property to the component

1.	Select the component Tube_box in the Model browser.

2.	In the Entity Editor, for Prop_Id, click Unspecified > Property

3.	In the Select Property dialog, select Pshell and click OK.

4.	In the Entity Editor, for Mat_Id, click Unspecified > Material.

5.	In the Select Material dialog, select Steel and click OK.

rd3530_03

Step 6: Create Rigid Body

1.	Create a component collector RBODY. Set Card Image to None in the Entity Editor.

2.	In the 1D page, select rigids.

3.	Set nodes 2-n to multiple nodes.

4.	Set primary node tab to calculate node.

5.	Select the nodes of one edge to tie all the degree’s of freedom, as shown in the image below:

rd3530_node

6.	Click create.

Step 7: Create Symmetry Boundary Conditions

1.	Click Tools > BCs Manager to start the BCs Manager.

2.	For Name, enter Symmetry, set Select type as Boundary Condition and set GRNOD to Nodes.

rd3530_bc

3.	Click on the nodes, nodes selection appears; by window option, select the top layer of the channel as shown below and the selection should appear as below:

rd3530_nodes_top

4.	Fix the degrees of freedom for symmetry condition, as shown below:

rd3530_bc_sym

5.	Click Create to create the constraint. The created constraint appears in the table, and a handle appears in graphics area.

Step 8: Create Imposed Velocity

1.	For Name, enter Velocity, set Select type as Imposed Velocity and set GRNOD to Nodes.

rd3530_velocity

2.	Select the master node of the RBODY on which the boundary condition needs to be applied.

rd3530_rbody

3.	Set the Direction as Z.

4.	Click Create/Select curve to create imposed velocity loading curve. A new GUI opens.

5.	Click New to enter Load as the name of the curve.

6.	Click proceed.

7.	Enter the X values as 0, 1000.

8.	Enter corresponding Y values as 13.3, 13.3.

rd3530_curve_editor_12

9.	Click the Create tab to create the constraint. The created constraint appears in the table and a handle appears in graphics area.

Step 9: Create boundary condition on the rigid body

1.	Enter Name as RBODY_constraint, set Select type as Boundary Condition and set the GRNOD to Nodes.

2.	Select the master node of the RBODY on which the boundary condition need to be applied.

3.	Set the degrees of freedom to not allow movement in X and Y direction and no rotation about Y-axis and Z-axis, as shown below.

rd3530_bc_13

4.	Click the Create tab to create the constraint. The created constraint appears in the table and a handle appears in graphics area.

Step 10: Create a Rigid Wall

1.	In the Model browser, right-click and select Create > Rigid Wall.

2.	Set the Geometry Type as Infinite plane.

3.	Click on the Base node option and select extreme node opposite to rigid body edge.

rd3530_fric

4.	Set the normal vector using the N1, N2, N3 option, as shown below. Ensure that N3 is not active. Click Proceed.

rd3530_geometry_13

rd3530_norm_vector

Note: Keep N3 inactive.

5.	Set d (distance) value to 20.

rd3530_rigid_wall_14

6.	Go to Analysis > rigid walls panel.

7.	Move to the Geometry page. Click on the Edit tab besides base node and change the Z value to 10.0 to be away from the channel along the Z-axis.

8.	Click update.

Step 11: Creating a Self Contact to avoid self penetration during impact

1.	In the Model browser, right-click and select Create > Contact. The Entity Editor will open.

2.	Enter the Name as Self_Interface and set the Card Image as TYPE7 and click Yes to confirm.

3.	Toggle the option to Components for Grnod_id (S) (slave entity), select Tube_box and click OK.

4.	Toggle the option to Components for Surf_id (M) (master entity), select Tube_box and click OK.

5.	Set STFAC = 1, FRIC = 0.20 and GAPmin = 0.90.

rd3530_self_interface

6.	Click anywhere in the Model browser to exit the Entity Editor.

7.	To review the created interface, go to the Analysis > Interface panel.

8.	Go to the update subpanel, select created interface and click review. It will show master and slave surface as blue and red.

Step 12: Create output requests 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	Box_Tube
ENGINE KEYWORDS	RUN	Status	[Checked]
ENGINE KEYWORDS	RUN	Tstop	10.01
ENGINE KEYWORDS	PRINT	Status	[Checked]
ENGINE KEYWORDS	PRINT	N_Print	-100
ENGINE KEYWORDS	ANIM/ELEM	Status	[Checked]
ENGINE KEYWORDS	ANIM/ELEM	EPSP	[Checked]
ENGINE KEYWORDS	ANIM/ELEM	ENERGY	[Checked]
ENGINE KEYWORDS	ANIM/ELEM	VONM	[Checked]
ENGINE KEYWORDS	ANIM/ELEM	HOURG	[Checked]
ENGINE KEYWORDS	ANIM/VECT	Status	[Checked]
ENGINE KEYWORDS	ANIM/VECT	VEL	[Checked]
ENGINE KEYWORDS	ANIM/VECT	FOPT	[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
ENGINE KEYWORDS	ANIM/NODA	Status	[Checked]
ENGINE KEYWORDS	ANIM/NODA	DMAS	[Checked]

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.	Enter the name boxtube 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 the engine file with the model file.

6.	Click Export to export the file.

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 boxtube_0000.rad.

rd3530_radioss_mgr

Step 15: Results analysis in HyperView

Exercise Expected Results

rd3530_results_14

Total Displacement (mm) and Plastic Strain (Mid Layer, Simple Average)

RD-3530: Buckling of a Tube using Half Tube Mesh

RD-3530: Buckling of a Tube using Half Tube Mesh

RD-3530: Buckling of a Tube using Half Tube Mesh

Model Description

Exercise

Exercise Expected Results

See Also: