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Influence of Geometrical Parameters on Rupture Risk of Abdominal Aortic Aneurysm
Zemánek, Miroslav ; Janíček, Přemysl (oponent) ; Tonar,, Zbyněk (oponent) ; Holeček, Miroslav (oponent) ; Burša, Jiří (vedoucí práce)
The main objective of this thesis is finite element and experimental modeling of stress-strain states of the soft tissues specially focused on rupture risk of abdominal aortic aneurysm (AAA). The first chapter (chap. 1) summarizes the present state of the mentioned problematic and the major information published in the present-day literature. The key factors for AAA rupture risk decision are also summarized in this chapter. The next chapter (chap. 2) describe the artery wall histology, type of aneurysms and mechanical behavior of artery wall. The second part of the thesis (chap. 3) is focused on experimental modeling of stress-strain states of soft tissues which is necessary for reliable finite element modeling of this behavior. In this chapter a specially designed and produced experimental testing rig is described and the type of tests which is possible to realize with this testing rig. The key factors influencing the stress-strain behavior of the aortic tissue are also summarized and experimentaly tested on porcine thoracic aortas. The new knowledge resulting from experimental testing are summarized at the end of this chapter. The intention of third part (chap. 4) is the mathematical description of the stress-strain behavior of soft tissues, description of frequently used constitutive models and the parameter identification for these constitutive models based on the realized tension tests. The last chapter (chap. 5) is devoted to finite element modeling of the stress-strain states of AAA behavior. First the key factors and assumptions for finite element models creation and evaluation are summarized as well as the material parameters of the constitutive models which are implemented in ANSYS software. Several simulations were realized using hypothetical AAA geometry where the impact of some geometrical parameters change was tested. The backward incremental method using for evaluation of unloading state was designed and tested at real AAA geometry reconstructed from CT scans. Hypertension as one of the key factor for AAA rupture risk was tested using unloaded geometry. The new knowledge and possibilities of finite element modeling are summarized at the end of this thesis. The proposals to next research work is also summarized.
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Influence of Geometrical Parameters on Rupture Risk of Abdominal Aortic Aneurysm
Zemánek, Miroslav ; Janíček, Přemysl (oponent) ; Tonar,, Zbyněk (oponent) ; Holeček, Miroslav (oponent) ; Burša, Jiří (vedoucí práce)
The main objective of this thesis is finite element and experimental modeling of stress-strain states of the soft tissues specially focused on rupture risk of abdominal aortic aneurysm (AAA). The first chapter (chap. 1) summarizes the present state of the mentioned problematic and the major information published in the present-day literature. The key factors for AAA rupture risk decision are also summarized in this chapter. The next chapter (chap. 2) describe the artery wall histology, type of aneurysms and mechanical behavior of artery wall. The second part of the thesis (chap. 3) is focused on experimental modeling of stress-strain states of soft tissues which is necessary for reliable finite element modeling of this behavior. In this chapter a specially designed and produced experimental testing rig is described and the type of tests which is possible to realize with this testing rig. The key factors influencing the stress-strain behavior of the aortic tissue are also summarized and experimentaly tested on porcine thoracic aortas. The new knowledge resulting from experimental testing are summarized at the end of this chapter. The intention of third part (chap. 4) is the mathematical description of the stress-strain behavior of soft tissues, description of frequently used constitutive models and the parameter identification for these constitutive models based on the realized tension tests. The last chapter (chap. 5) is devoted to finite element modeling of the stress-strain states of AAA behavior. First the key factors and assumptions for finite element models creation and evaluation are summarized as well as the material parameters of the constitutive models which are implemented in ANSYS software. Several simulations were realized using hypothetical AAA geometry where the impact of some geometrical parameters change was tested. The backward incremental method using for evaluation of unloading state was designed and tested at real AAA geometry reconstructed from CT scans. Hypertension as one of the key factor for AAA rupture risk was tested using unloaded geometry. The new knowledge and possibilities of finite element modeling are summarized at the end of this thesis. The proposals to next research work is also summarized.
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Určování mechanických vlastností věnčitých tepen
Beneš, J. ; Horný, L. ; Konvičková, S. ; Chlup, Hynek
Pomocí tlakových experimentů bylo zjišťováno konstitutivní chování lidských věnčitých tepen. Sledována byla závislost poloměru tepny na vnitřním tlaku a podélném předpětí. Experimentálně získaná data byla později použita k určení materiálových parametrů, které vystupují ve funkci hustoty deformační energie. Byl použit logaritmický tvar hustoty deformační energie.
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Kriterium minimální hustoty deformační energie v případě namáhání tělesa s V-vrubem
Klusák, Jan
Příspěvek je věnován návrhu kriteria stability těles s V-vruby zatěžovaných jednoduchým módem I nebo II nebo kombinací módů I a II. Metodika návrhu kriteria stability vychází z analogie chování těles s trhlinou a V-vrubem. V článku je nejprve ukázáno rozložení hustoty deformační energie v okolí tělesa s V-vrubem, poté je určen směr šíření trhliny z V-vrubu při kombinovaném namáhání a nakonec je proveden návrh lomových kriterií.
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