Contents
Description
- This example guides you through setting up and running a physical and material nonlinear bi-axial stretch test of a passive (non-contracting) cube using displacement boundary conditions.
- The mesh is a simple one-element cube with tri-linear basis functions. The boundary conditions assure that all rigid body motions are suppressed, and that the cube is stretched in two perpendicular directions. The material chosen is a transversely isotropic exponential strain energy function. The material is stiffer in the fiber direction than perpendicular to them.
Start Continuity
- Launch the Continuity Client
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On the About Continuity startup screen
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Leave the mesh checkbox checked under Use Modules:
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In addition, check the biomechanics checkbox
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Click OK to bring up the main window
Create mesh
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Select the cont6 file for this tutorial (cubemesh.cont6)
- To make sure you selected the right cont6 file, verify the following:
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Check that the list contains only Linear-Linear-Linear Lagrange 2*2*2and Linear-Linear Lagrange 2*2
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- Check that that there are only 8 nodes defined
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- Check that there is only 1 element in the list
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If the Dimensions Form appears, simply click Apply Marked Recommendationsand then OK
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Click the lines radio button
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Click Render to display mesh lines
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- The mesh should now look like the following screenshot:
Add biomechanics data
- Load the required biomechanics model from the database
- File→Library→Search…
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In the window near the top, enter ‘lagrangian’ and hit return.
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From the listed models select BM_TI_of_Lagrangian_strains_comp_sympy by right-clicking on it and selecting ‘Load’
- When the warning window display, select the third choice: ‘Retain current problem but overwrite the following objects: [dims, renderer, matEquations]’
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Biomechanics→Update→Initial conditions with undeformed nodes
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After having opened the two forms, ensure that the Boundary Conditions form has the same basis functions as the Nodes Form
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Biomechanics→Edit→Boundary Conditions…
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Click on the Deformed Coordinates 1 tab
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Click the Insert Nodes button two times
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Click on node 1 in the list
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Enter 1,3,5,7 in the Node(s) text field, and hit Enter
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Click on node 2 in the list
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Enter 2,4,6,8 in the Node(s) text field, and hit Enter
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Enter 0.25 in the Value text field
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Click on the Deformed Coorinates 2 tab
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Click the Insert Nodes button two times
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Click on node 1 in the list
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Enter 1,2,5,6 in the Node(s) text field, and hit Enter
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Click on node 2 in the list
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Enter 3,4,7,8 in the Node(s) text field, and hit Enter
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Enter 0.25 in the Value text field
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Click on the Deformed Coorinates 3 tab
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Click the Insert Nodes button four times
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Click the OK button
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If the Dimensions Form appears, simply click Apply Marked Recommendationsand then OK
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Change the Time Step to 0.1
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Change the Number of Steps to 10
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Click the Solve button, and wait for the solver to finish its job
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Click the lines radio button
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This time select the deformed radio button is selected
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Click Render to display mesh lines
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- The mesh should now look like the following screenshot:
Pre-built model
This cont6 file contains all data and parameters for this problem, right before the biomechanics solve: bm1.cont6