BME/ME 506
Computational Modeling
of Biological Tissues

Overview:

       Biological tissues are complex structures subjected to a number of external stimuli including mechanical forces, electrical signals, and heat.  The structure of these tissues determines their response to these stimuli.  In addition, cells within the tissues can sense the stimuli and adapt or change the tissue matrix structure.  Understanding the physical behavior of tissues and their adaptation is important from a scientific perspective and in many clinical areas for treating diseased or damaged tissue.

        Due to the complexity of tissue behavior, and the need to quantity tissue physics for scientific and design purposes, many researchers have applied computer modeling to simulate tissue behavior.  However, biological tissues differ in many ways from typical engineering materials.  First, biological tissues are extremely heterogenous within a single body and between individuals, whereas many engineering components are mass produced, each component having the same structure, material, etc.  Second, there are no blueprints or CAD files for tissues, we obtain all information on tissue structure from either digital imaging or histology.  Third, tissues always have hierarchical structures with many different scales, more than the typical engineering composite.  Fourth, tissues have the ability to change their structure in response to external stimuli, something not done by most engineering materials outside of the normal processes of damage and degradation.

        This class is geared towards presenting aspects of computational modeling that are specific to biological tissues and are generally not found in classic computer aided engineering. These aspects include the visualization techniques to handle image data since most data on tissues comes from images, the use of homogenization theory to handle multiscale tissue hierarchy, modeling tissue adaptation, and a brief overview of geometric versus image based modeling.   The course will cover three major areas:

1.        Visualization and Model Pre/Post-Processing
2.        Analysis of Hierarchical Tissue Physics
3.        Modeling of Tissue Adaptation

Final Project/Last Class Information

The final project may be presented on the last day of class or during the time of the scheduled final, depending on the number of students in class and the class decision.

Pertinent Information

Instructor:  Scott J. Hollister
Office:  3414 GG Brown Building
Email:  scottho@umich.edu
Phone:  (734) 647-9962

Course Requirements

1-2 Computational Homework Assignments
1 Computational Term Project

Ideas for Class Project

Homework #1

Dates for Media Union Classes:

Wednesday, Sept 18 - Windows Classroom 2
Monday, Sept 30 - Windows Classroom 1
Monday, Oct. 28- Windows Classroom1
Monday, Nov. 25 - Windows Classroom 1

Note: I have now placed .stl, .hm (Hypermesh), and .inp (Abaqus input) file for
a human liver CT scan in the directory /afs/engin.umich.edu/class/perm/bme506/livermesh if
you would like to try this in Hypermesh/Abaqus. All previous IDL programs have been moved
to /afs/engin.umich.edu/class/perm/bme506/idlprograms.   All data .thr for trabecular bone has
been moved to /afs/engin.umich.edu/perm/bme506/trabbonedata.

Finally, if you are running Hypermesh/Abaqus on CAEN Sun machines, you can put the following command
in your .my-alias file: alias hmabaqus 'usr/caen/hyperworks-3.0/altair/translators/3.0/bin/SOLARIS/hmabaqus'
Then to translate Abaqus results to Hypermesh format you type hmabaqus file.fil file.hmres, where file.fil is
the Abaqus results file and file.hmres is the Hypermesh results file. Note, you can give the Hypermesh results
file any extension you would like, that is the one I use.

Course Schedule   

Course Lectures

I.  Introductory/Philosophy Lectures

    1. Modeling Classifications

     2. Computational Modeling Paradigm

     3. A Simple Modeling Example

II.  Visualization/Pre-Processing Lectures

    1. Representing Topology

     2. Visualizing Topology

     3.  Introduction to IDL for Visualization

     4.  Creating Graphical User Interfaces (GUI) for Visualization -          Widget Programming in IDL

     5.    Basic Overview of Steps from Image to Unstructured or Structured Mesh Generation 

III.  Formulation/Processing Lectures

     1. Finite Element Formulation for Potential Problems (Electrical Conduction, Heat Conduction, Fluid Flow Through Porous Media)

     2. Homogenization Formulation for the Multilevel Potential Problem

     3. Homogenization Formulation for the Multilevel Diffusion Problem

     4. Finite Element Formulation for Small Deformation Elasticity

     5. Homogenization Formulation for Small Deformation Elasticity

     6. Computational Simulation of Bone Adaptation

     7. Homogenization Formulation for Fluid Flow through Porous Tissue

     8. Nonlinear Analysis Preliminary: Stress, Strain and Constitutive Defintions

     9. Finite Element Formulation for Nonlinear Hyperelastic Material undergoing Large Deformation

BME 506 Home