Razvoj postupka određivanja materijalnih parametara hiperelastičnog modela iz pokusa istezanje - tlak

master's thesis

• Title (english): Mechanical characterization of hyperelastic material model from extension - inflation test
• Author: Iskra Knapp
• Mentor: Igor Karšaj (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2020-12-04, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; General Mechanical Engineering (Construction)

Abstract

U ovom radu analiziran je utjecaj eksperimentalnih parametara na točnost određivanja materijalnih parametara prilikom pokusa istezanje - tlak na modelu arterije. Napravljena je simulacija eksperimenta istezanje - tlak, u programskom paketu Abaqus, za nestlačivi model arterije opterećen na intraluminarni tlak i aksijalnu silu, odnosno pomak u aksijalnom smjeru koji predstavlja predistezanje arterije. Simulacija je napravljena za tri hiperelastična materijalna modela od kojih dva opisuju izotropno ponašanje, Neo-Hooke i Mooney-Rivlin, te Holzapfel-Gasser-Ogden koji opisuje anizotropno ponašanje. Iz simulacije eksperimenta dobiveni su podaci promjene unutarnjeg i vanjskog radijusa stijenke arterije, unutarnjeg tlaka i aksijalne sile. Podaci dobiveni iz simulacije uspoređeni su s izračunatim podacima za sva tri materijalna modela, te su pomoću metode najmanjih kvadrata, za odgovarajuću funkciju cilja, određeni materijalni parametri za sva tri slučaja. Određivanje materijalnih parametara provedeno je pomoću programskog paketa Octave. Nakon što je potvrđena točnost simulacije eksperimenta i korištenog proračuna, ispitan je utjecaj promjene aksijalnog predistezanja i cirkularnog istezanja na određivanje materijalnih parametara, te su prikazani rezultati analize za sva tri materijalna modela.

Abstract (english)

In this paper, the influence of experimental parameters on the accuracy of determination of material parameters during the extension - inflation experiment on an artery model is analyzed. A simulation of the extension - inflation experiment was made, in the Abaqus software package, for an incompressible artery model loaded with intraluminal pressure and axial force, i.e. a displacement in the axial direction which represents the prestretch of the artery. The simulation was made for three hyperelastic material models of which two describe isotropic behavior, Neo-Hooke and Mooney-Rivlin, and Holzapfel-Gasser-Ogden describing anisotropic behavior. From the simulation of the experiment, data regarding the change of the inner and outer radii of the artery wall, internal pressure and axial force were obtained. The data obtained from the simulation were compared with the calculated data for all three material models, and using the minimizing method, for the corresponding objective function, the material parameters for all three cases were determined. The determination of material parameters was performed using the Octave software package. After confirming the accuracy of the simulation and the calculation used, the influence of the change in axial prestretch and circular stretching on the determination of material parameters was examined, and the results of the analysis for all three material models were presented.

• Keywords: arterije; hiperelastičnost; materijalni parametri; metoda konačnih elemenata; Neo-Hooke; Mooney-Rivlin; Holzapfel-Gasser-Ogden
• Keywords (english): arteries; hyperelasticity; material parameters; finite element method; Neo-Hooke; Mooney-Rivlin; Holzapfel-Gasser-Ogden
• Language: croatian
• URN:NBN: urn:nbn:hr:235:279084
• 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: 2020-11-26 15:47:52