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| * Ahmet informed the University of Utah team that he has slowed down the project. | * Ahmet informed the University of Utah team that he has slowed down the project. Ongoing activities are mostly tedious and include tissue testing and geometry generation. * Ahmet also noted that he prepared a simple femur-acl-tibia model as a sample problem for cloud computing. While doing so, he tried convergence settings and explored the possibility to use rigid body kinematic constraints to prescribe joint movements. He mentioned that the convergence when using constraints was not possible all the time. Prescribing movements using traditional rotation axis - angle based strategy converged all times at faster rates. * Ahmet and Jeff also discussed providing letters of support for a grant application by Simbios. This was requested recently by Joy Ku. |
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| * | * Steve has worked on what he calls deformable springs, which are serial piece-wise arrangement of springs to allow wrapping. |
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1. Recap of action items from past meetings. * Action items were mostly related to agenda of the meeting; see notes below. 1. Deformable springs with contact. * Steve implemented springs elements that can wrap around objects through contact. He had some convergence issues. In following, he identified the potential problem to be based on setting up the assembled stiffness matrix for prescribed displacement. Steve thought that he can resolve this issue. * Jeff asked about a particular knee model that can be used as example for representation of ligaments with springs wrapping around bones. Ahmet noted that the model they used for the in situ strain manuscript can serve well. Yet, he also asked for the possibility to setup in situ strain (or slack length) for deformable springs. Another question was related to nonlinear springs. Current implementation is limited to linear formulation. Steve may need to calculate the whole length of the structure modeled as a series of springs and may have to implement features to distribute an overall stiffness property to a series of springs. Ahmet recommended him to chat with Jason Halloran; he will e-mail Jason and Steve to start the discussion. 1. Shell element formulations. * For shell elements, Gerard Ateshian came up with an idea to setup an initial formulation to couple shell elements to solid elements. Steve will follow up with Gerard. 1. Discrete element analysis. * Discrete element analysis will be explored if and when the group can allocate time for it. 1. Decide action items for next meeting. * See Immediate Action Items above. 1. Other. * Jeff mentioned that in their FEBio meeting they discussed developing a SimTk community for FEBio. Everyone seemed to be interested in and willing to create project pages there. Ahmet asked Jeff to get FEBio users' in touch with him in case they need help to use SimTk site, e.g. setup projects, etc. |
Recurring Meeting of Cleveland Clinic - University of Utah
Date: September 14, 2016
Time: 2:00 PM EST
Means: Conference call
Attendees:
- Ahmet Erdemir (Cleveland Clinic)
- Jeff Weiss (University of Utah)
- Steve Maas (University of Utah)
- Ben Ellis (University of Utah)
Agenda:
- Ongoing and planned activities at Cleveland Clinic.
- Ongoing and planned activities at University of Utah.
- Other.
Immediate Action Items:
- Cleveland Clinic (Ahmet)
- University of Utah (Jeff)
- University of Utah (Steve)
- Explore generalization of wrapping spring elements feature for nonlinearity and for model setup.
- Follow up with Gerard Ateshian about formulations for shell elements on solid elements.
Notes:
- Ongoing and planned activities at Cleveland Clinic.
- Ahmet informed the University of Utah team that he has slowed down the project. Ongoing activities are mostly tedious and include tissue testing and geometry generation.
- Ahmet also noted that he prepared a simple femur-acl-tibia model as a sample problem for cloud computing. While doing so, he tried convergence settings and explored the possibility to use rigid body kinematic constraints to prescribe joint movements. He mentioned that the convergence when using constraints was not possible all the time. Prescribing movements using traditional rotation axis - angle based strategy converged all times at faster rates.
- Ahmet and Jeff also discussed providing letters of support for a grant application by Simbios. This was requested recently by Joy Ku.
- Ongoing and planned activities at University of Utah.
- Steve has worked on what he calls deformable springs, which are serial piece-wise arrangement of springs to allow wrapping.
- Other.