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Dynamic modelling of a stented aortic valve
Thesis (MScEng (Mechanical and Mechatronic Engineering))--Stellenbosch University, 2008.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2008
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| _version_ | 1867613882544029696 |
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| access_status_str | Open Access |
| author | Van Aswegen, Karl |
| author2 | Scheffer, C. |
| author_browse | Scheffer, C. Van Aswegen, Karl |
| author_facet | Scheffer, C. Van Aswegen, Karl |
| author_sort | Van Aswegen, Karl |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScEng (Mechanical and Mechatronic Engineering))--Stellenbosch University, 2008. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/1923 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:43:12.690Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2008 |
| publishDateRange | 2008 |
| publishDateSort | 2008 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/1923 Dynamic modelling of a stented aortic valve Van Aswegen, Karl Scheffer, C. Groenwold, A. A. Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. Fluid structure interaction Prosthetic heart valve -- Design Aortic valve Dissertations -- Mechanical engineering Theses -- Mechanical engineering Aortic valve -- Stenosis Heart valve prosthesis Mechanical and Mechatronic Engineering Thesis (MScEng (Mechanical and Mechatronic Engineering))--Stellenbosch University, 2008. Aortic valve replacements are frequently performed during heart surgery. However, since this is quite a stressful procedure, many patients are turned down for medical reasons. Stented valves, designed and manufactured for percutaneous insertion, eliminate many of the risks involved in open-heart surgery, thus providing a solution to patients not deemed strong enough for open-chest aortic valve replacements. The aortic valve is a complex structure, and therefore numerical simulation is necessary to obtain flow and stress data to support the design of a prosthetic heart valve in the absence of viable physical measuring methods. To aid in the design of a prosthetic heart valve, various finite element valve models were created, and the fluid structure interaction (FSI) between the valves and the blood was simulated using commercial finite element software. The effect of the geometry of the leaflets on the haemodynamic behaviour over the cardiac cycle was investigated. It was found that leaflet dimensions should be chosen judiciously, because of their considerable effect on the stress distribution and performance of the valve. A simple leaflet geometry optimisation was done for a 20 mm and 26 mm valve, respectively, by means of existing geometry relationships found in the literature. Simulations were done to obtain the maximum leaflet attachment forces that can be used by a stent designer for fatigue loading, or to investigate the structural strength of the stent. These simulations were numerically validated. The effect of leaflet thickness and stiffness on resistance to opening, stress distribution and strain were investigated. Results showed that leaflet thickness has a greater effect on the performance of the valve than leaflet stiffness, and thereby validated the results of similar tests contained in the literature. After simulating over-, as well as under-dilation of a stented valve, it was found that problems associated with over-dilation can be minimised to a certain extent by increasing the coaptation1 region of the leaflets. A simple pulse duplicator was designed based on a four-element Windkessel model. The pulse duplicator was used to study the performance of the prototype valves by means of high-speed photography, the results of which were fed into one of the numerical finite element models and compared to real valve performance. Some of the prototype valves showed efficiencies of 88%. 2008-11-17T13:20:41Z 2010-06-01T08:36:43Z 2008-11-17T13:20:41Z 2010-06-01T08:36:43Z 2008-12 Thesis http://hdl.handle.net/10019.1/1923 en Stellenbosch University application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Fluid structure interaction Prosthetic heart valve -- Design Aortic valve Dissertations -- Mechanical engineering Theses -- Mechanical engineering Aortic valve -- Stenosis Heart valve prosthesis Mechanical and Mechatronic Engineering Van Aswegen, Karl Dynamic modelling of a stented aortic valve |
| title | Dynamic modelling of a stented aortic valve |
| title_full | Dynamic modelling of a stented aortic valve |
| title_fullStr | Dynamic modelling of a stented aortic valve |
| title_full_unstemmed | Dynamic modelling of a stented aortic valve |
| title_short | Dynamic modelling of a stented aortic valve |
| title_sort | dynamic modelling of a stented aortic valve |
| topic | Fluid structure interaction Prosthetic heart valve -- Design Aortic valve Dissertations -- Mechanical engineering Theses -- Mechanical engineering Aortic valve -- Stenosis Heart valve prosthesis Mechanical and Mechatronic Engineering |
| url | http://hdl.handle.net/10019.1/1923 |
| work_keys_str_mv | AT vanaswegenkarl dynamicmodellingofastentedaorticvalve |