Tricubic Cartesian Canine Example

Description

  • This example guides you through setting up and running a physical and material nonlinear problem of the contraction of a dog heart in the circulation.
  • The mesh of the left and right ventricle was fitted to a dog heart. The basis functions for the mesh coordinates are cubic in all directions (cubic-cubic-cubic) and tri-linear for the fiber architecture. The passive material chosen is a transversely isotropic exponential strain energy function. Pressure is prescribed on the LV and RV endocardium, and is computed by a lumped-parameter systems model of the closed circulation. Active stress is calculated by a varying-elastance type cellular model (Guccione model) and is added to the passive stress in the fiber direction. A fraction of the active stress is also added to the passive stress perpendicular to the fibers. Active stress is dependent on time, sarcomere length (which is proportional to fiber strain), and calcium concentration.

Start Continuity

  • Launch the Continuity 6.3 Client
  • On the About Continuity 6.3 startup screen

    • Leave the mesh checkbox checked under Use Modules:

    • In addition, check the biomechanics checkbox

  • Click OK to bring up the main window

Create mesh

Solve biomechanics

  • If the Biomechanics menu is not loaded, select File→Load Continuity Modules...

    • Select biomechanics and click OK

    • The menu bar should now show the Biomechanics command
  • Biomechanics→Solve Nonlinear...

    • For Time Step, enter 4.0

    • For Number of Steps, choose 1

    • For when number of iterations >, enter 150

    • For when sum of solution increments <, enter 1e-005

    • For when sum of unconstrained residuals <, enter 1e-005

    • Click Solve, and wait for the solver to finish

  • Biomechanics→Render→Strain...

    • Select the deformed radio button on the bottom

    • Click Render

  • The mesh should now look similar to the last two screenshots, viewed from different angles.

Pre-built model

This cont6 file you used above for this problem already contains all data and parameters, right up to the biomechanics solve.