RD-T: 3030 Buckling of a Tube Using Half Tube Mesh

This tutorial 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.

rd3030_model
Figure 1. Model

The model description is as follows:

  • 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 = 0.3

[a] Yield Stress = 0.206 GPa

[b] Hardening Parameter = 0.450 GPa

[n] Hardening Exponent = 0.5

Model Files

Refer to Access the Model Files to download the required model file(s).

Input file for this tutorial: BOXTUBE_0000.rad

Start HyperCrash

  1. Open HyperCrash.
  2. Set the User profile to RadiossV2021 and the Unit system to kN mm ms.kg.
  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 BOXTUBE_0000.rad.
  8. Click OK.

Create and Assign a Material

  1. Click Model > Material.
  2. In the Material tab, right-click and choose Create New > Elasto-plastic > Johnson-Cook (2).

    rd3030_create_new
    Figure 2.
  3. For Title, enter Steel.
  4. Enter all the material data, as shown.

    rd3030_plas_johns
    Figure 3.
  5. Right-click in the Support entry box and click Select in graphics.
  6. Select Include picked parts selectpartgeneral-24 and select boxtube in the modeling window.
  7. Press Enter, or click Yes in the lower right corner.
  8. Click Save and then click Close.

Create and Assign a Property

  1. Click Model > Property.
  2. In the Property tab, right-click and select Create New > Surface > Shell (1).

    rd3030_create_surface_12
    Figure 4.
  3. For Title, enter Pshell.
  4. For Shell thickness, enter 0.914.

    rd3030_shell
    Figure 5.
  5. Right-click in the Support entry box and click Select in graphics.
  6. Select Include picked parts selectpartgeneral-24 and select boxtube in the modeling window.
  7. Press Enter, or click Yes in the lower right corner.
  8. Click Save and then click Close.

Define the Rigid Body

  1. Click Mesh Editing > Rigid Body. Right-click in the Rigid Body tab and select Create New.
  2. Right-click in the modeling window and select Add nodes by box selection icon selectbyboxadd-24 to select the nodes in the modeling window, as shown below:

    rd3030_rigid_body
    Figure 6.
  3. Press Enter or click Save to validate.

    rd3030_rigid_body2
    Figure 7.
    Note: For the remainder of the tutorial, you need to have the ID of the main node of the rigid body.
  4. Click Show Node Info icon node_information in the toolbar, and select the rigid body main node in the modeling window.
    The Node ID appears in the message window (node ID: 803).
  5. Click Cancel in the lower right corner to exit the picking loop.
  6. Click Close.

Define Boundary Conditions

  1. Click LoadCase > Boundary Condition.
  2. Right-click in the Boundary Condition tab and select Create New.
  3. In the Title field, enter the name Rigid_BC.
  4. In the Node by Id field, enter 803, then click Ok.
  5. To constrain the nodes, toggle Tx, Ty, Rx, Ry and Rz.

    rd3030_bc1
    Figure 8.
  6. Click Save.

Define Boundary Conditions Representing Symmetry

  1. In the Boundary condition display list area, select Create New.
  2. Name the new constraint set symmetry.
  3. Right-click in the Support entry box and click Select in graphics.
  4. Select Add nodes by box selection icon selectbyboxadd-24 to select the nodes in the modeling window, as shown below:

    rd3030_bc2
    Figure 9.
  5. Right-click to validate.
  6. Toggle Tx, Ry and Rz.
  7. Click Save, then click Close.

Define the Imposed Velocity

  1. Click LoadCase > Imposed > Imposed Velocity. Right-click in the tab and select Create New > Imposed Velocities.
  2. For Title, enter VELOCITY.
  3. Right-click in the Time function parameter entry box and select Define Functionfun.
    A Function Window opens.
  4. For the function name, enter FUNC_VEL.
  5. Enter the first point (0, 13.3) and click Validate.
  6. Enter the second point (1e30, 13.3) and click Validate.
  7. Click Save in the Function Window to accept the function.
  8. Expand the Advanced selector at the bottom and in the Node by Id field, enter 803 and click Ok, (or toggle Add RB main nodes).
  9. Go to the Properties tab and enter a Y-Scale factor = -1.
  10. Set the Direction* filed to Z (translation).
  11. Click Save and then click Close.

    rd3010_imposed_velocity
    Figure 10.

Define a Rigid Wall

  1. Click LoadCase > Rigid Wall > Create.
  2. In the Rigid Wall tab, right-click and select Create new > Rigid Wall > Plane.
  3. For Select RWALL, select Infinite Plane.
  4. For Title, enter RIGID WALL.
  5. Enter the following values:
    M0:
    X= 0
    Y= 38.1
    Z= -204
    M1:
    X= 0
    Y= 38.1
    Z= 1
  6. In the Distance for secondary search field, enter 20.
    Note: Click Advanced Selector for more options.
  7. Toggle See.
  8. Click See to visualize it in the modeling window.

    rd3030_rigid_wall
    Figure 11.
  9. Click Save, then click Close.

Create a Self Contact for the Tube

  1. Click LoadCase > Contact Interface.
  2. Right-click in the Contact Interface tab and select Create New > Multi usage (Type 7).
  3. Toggle Self impact.

    rd3030_self-impact
    Figure 12.
  4. Right-click in the modeling window, and select Include picked parts icon selectpartgeneral-24 and select the part in the modeling window.
  5. Click Yes in the lower right corner of the main window to validate.
  6. For Title, enter the name Contact.
  7. Set Scale factor for stiffness as 1.
  8. Set Min. gap for impact active to 0.900.
  9. Set Coulomb friction to 0.200.
  10. Click Save, then click Close.

Export the Model

  1. Under the Model menu, select Control Card.
  2. Check Control Card to activate it.
    Note: Make sure to save it before moving to the next Control Card.

    rd3030_control_card
    Figure 13.

    rd3030_control_card2
    Figure 14.

    rd3030_control_card3
    Figure 15.

    rd3030_control_card4
    Figure 16.
  3. Click File > Export > Radioss.
  4. In the Write Block Format 2021 Radioss File window that opens up, enter the name as BOXTUBE and click OK.
  5. Leave the Header of Radioss File window empty and click Save Model.
    The Starter file BOXTUBE_0000.rad is written. The model is now ready to run through the Starter and the Engine.

Open Compute Console from the Windows Start Menu



Figure 17.

Review the Results

Using HyperView, plot the displacement and strain contour at 10 ms.


Figure 18.