De Vita, Raffaella
(2003)
Modeling Bovine Pericardium.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Bovine pericardium has been widely used over the last decades as bioprosthetic material due to its excellent biocompatibility. However, the durability of pericardial heart valves is still inadequate and prevents them from being the perfect heart valve substitutes. To increase their short-time performance, studying the tissue mechanical features is of prime importance. Consequently, constitutive relations need to be developed.The purpose of this work was to analyze two different constitutive approaches used to model bovine pericardium: the phenomenological approach and the structural approach.Phenomenological constitutive laws are formulated to fit empirical data, independent of histological considerations. Their main drawback is the variability of material parameters for different protocols for the same specimen. Thus, they do not consent to interpret the tissue's mechanical behavior. In the second chapter, some physically sound restrictions on the parameters, which appear in some forms of the exponential Fung model, are obtained by invoking the Legendre-Hadamard and the Strong Ellipticity conditions. These restrictions can validate the empirical models and can be used in the fitting procedure. Structural constitutive equations are determined by taking into account the tissue's architecture. A structurally based constitutive law describing the tissue's mechanical response through failure behavior has been proposed in the third chapter. The model has been tested by using published experimental data and a sufficiently good fit has been obtained.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
8 May 2003 |
| Date Type: |
Completion |
| Defense Date: |
2 February 2003 |
| Approval Date: |
8 May 2003 |
| Submission Date: |
3 April 2003 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Mechanical Engineering |
| Degree: |
MSME - Master of Science in Mechanical Engineering |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
bovine pericardium; Fung model; heart valves; order-preserving inequalities; structural model |
| Other ID: |
http://etd.library.pitt.edu:80/ETD/available/etd-04032003-205525/, etd-04032003-205525 |
| Date Deposited: |
10 Nov 2011 19:33 |
| Last Modified: |
15 Nov 2016 13:38 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/6712 |
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