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Type of Document Master's Thesis Author Mitchell, Brent Spanjersberg Author's Email Address brent.mitchell@gmail.com URN etd-07192006-222128 Title A Nonlinear Constitutive Model to Predict the Stress Strain Behavior of Small Intestinal Submucosa Degree Master of Science in Mechanical Engineering Department Aerospace and Mechanical Engineering Advisory Committee
Advisor Name Title Glen L. Niebur Committee Chair Diane Wagner Committee Member Ryan Roeder Committee Member Keywords
- small intestinal submucosa
- SIS
- Constitutive model
- nonlinear
Date of Defense 2006-06-15 Availability unrestricted Abstract Porcine small intestinal submucosa (SIS) is a bioactive resorbable extracellular matrix material (ECM) comprised mostly of collagen type I and containing the growth factors TGF-β and FGF-2. Current applications of this material consist of using SIS as a nonload-bearing device. However with its unique regenerative properties and nonlinear mechanical response, this material is a great choice for tendon or ligament replacement or repair. The development of this material to be used in a load-bearing application requires full understanding of its mechanical properties.A scaffold comprised of 20-layers of SIS sandwiched together was tested in a uniaxial tensile test. This test resulted in a nonlinearly elastic stress-strain response with a distinct toe-region, linear region, and strain to failure. To fully model this response, a nonlinear constitutive material model was developed using an exponential strain energy density function. As the ultimate tensile strength of this scaffold is lower than that of most tendons and ligaments, a polydiaxanone (PDS) mesh was incorporated into the 20-layer scaffold, which showed an increase in applied load with a decrease in ultimate tensile strength. In conclusion, a nonlinear constitutive model was developed to predict the nonlinear stress-strain response of a 20-layer multilaminate SIS scaffold which can serve as a building block to future development of a load-bearing bioresorbable scaffold.
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