Numerical analysis of dissection in thoracic aorta

Abstract

U radu su opisana temeljna znanja iz područja medicine i mehanike kontinuuma potrebna za razumijevanje napravljenog u sklopu ovog rada. Za numeričku analizu korišten je i opisan programski paket za metodu konačnih elemenata Abaqus. Kreiran je model zdrave aorte. Za zdravu aortu provedena je simulacija u kojoj se stijenka krvne žile smatra apsolutno krutom i u kojoj se stijenka smatra deformabilnom. Rješenja dobivena u simulaciji s krutom stijenkom uspoređena su s onim dobivenim za deformabilnu stijenku. Potom je izrađen model disekcije aorte te je definiran i opisan referentni slučaj. Rezultati dobiveni za referentni slučaj poslužili su pri definiranju ostala četiri slučaja za koje su provedene simulacije. Za sve slučajeve prikazani su rezultati za posmična naprezanja po duljini stijenke aorte. Na osnovu dobivenih rezultata izvedeni su zaključci. Utvrđeno je da se povećanjem ulazne brzine u lažni lumen posmična naprezanja po duljini vanjskog dijela stijenke pravog lumena povećavaju, dok se za unutarnji dio stijenke smanjuju.Basic theory in the areas of medicine and continuum mechanics needed for the understanding of this paper is explained in the beggining of the paper. Abaqus, finite element analysis software, that was used for numerical analysis is explained in this paper aswell. Model of a healthy aorta was created. This model was used for a simulation in which wall of the aorta is considered to be absolutely rigid and a simulation in which wall of the aorta is considered to be deformable. Results of this simulations were compared to each other. Furthermore, model of the dissection of aorta was created and reference case was defined aswell as described. Results of the reference case were used in defining other four cases for which the simulations were preformed. Results of wallshear along the length of aorta wall were shown for all cases. Conclusions were made on the basis of results. It was determineted that with the increase of entry speed in false lumen, wallshear along the length of the outer part of the real lumen is increased, while it is decreased along the inner part of the wall