Usporedba metoda za neinvazivno određivanje svojstava arterija

master's thesis

• Title (english): Comparison of methods for non-invasive determination of mechanical properties of arteries
• Author: Nino Pintarić
• Mentor: Lana Virag (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2024-07-16, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; General Mechanical Engineering (Construction)

Abstract

Cilj ovog rada je razviti numeričke te usporediti točnost neinvazivnih metoda računanja parametara materijala arterijske stijenke na temelju rezultata virtualnog eksperimenta. Metodom konačnih elemenata pomoću programskog paketa Abaqus simulirano je napuhivanje arterije tlakom uz konstantno aksijalno predistezanje. Na temelju rezultata simulacije zatim su nelinearnom metodom najmanjih kvadrata pomoću računalnog alata Octave izračunati parametri materijala. Verifikacijski, izveden je virtualni eksperiment te su određeni parametri materijala za Neo Hookeov materijalni model, uz provjeru utjecaja nepoznavanja pojedinih parametara te uz provjeru utjecaja razmatranog raspona tlaka.
Zatim je izveden virtualni eksperiment za Holzapfel-Gasser-Ogden materijalni model, utvrđen je utjecaj početnih pretpostavki na točnost rezultata te je utvrđen utjecaj nepoznavanja pojedinih parametara na točnost rezultata. Uspoređene su dvije predložene neinvazivne metode koje koriste dodatne fiziološke uvjete sa referentnom neinvazivnom metodom koja koristi samo ovisnost tlaka o trenutnom unutarnjem promjeru.

Abstract (english)

The aim of this paper is to develop numerical procedure and compare non-invasive methods of calculating the parameters of the arterial wall material based on the results of a virtual in silico experiment. Using the finite element method using the Abaqus software package, the inflation of the artery with internal pressure with constant axial prestretching was simulated. Based on the results of the simulation, the parameters of the material were then calculated using the nonlinear least squares method using Octave computer program. For verification, a virtual experiment was performed and the material parameters for Neo Hooke material model were determined, while determining the influence of ignorance of certain parameters and the influence of the considered pressure range.
Then a virtual experiment was performed for the Holzapfel-Gasser-Ogden material model. The influence of the initial assumptions on the accuracy of the results and the influence of ignorance of certain parameters on the accuracy of the results were determined. The two proposed non-invasive methods that use additional physiological conditions were compared with the reference non-invasive method that only uses the pressure dependence on the current internal diameter.

• Keywords: anizotropnost; hiperelastičnost; neo-Hooke; Holzapfel-Gasser-Ogden; metoda konačnih elemenata; arterijska stijenka; parametri materijala
• Keywords (english): anisotropy; hyperelasticity; neo-Hooke; Holzapfel-Gasser-Ogden; finite element method; arterial wall; material parameters
• Language: croatian
• URN:NBN: urn:nbn:hr:235:915874
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-07-12 17:50:12