Utjecaj predistezanja na određivanje mehaničkih svojstava mekih tkiva iz dvoosnog vlačnog testa

undergraduate thesis

• Title (english): The influence of prestretch on the mechanical characterization of soft tissues using biaxial tensile test
• Author: Nino Pintarić
• Mentor: Lana Virag (mentor)
• Committee member: Nastia Degiuli (predsjednik povjerenstva)
• Committee member: Nenad Bojčetić (član povjerenstva)
• Committee member: Neven Alujević (član povjerenstva)
• Committee member: Lana Virag (član povjerenstva)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2022-03-03, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Cilj ovog rada je ispitati utjecaj predistezanja prilikom dvoosnog vlačnog testa na točnost
određivanja parametara anizotropnog materijala poput mekog tkiva ili 3D ispisanih polimera.
Najprije je provedena numerička simulacija dvoosnog vlačnog testa s predistezanjem metodom
konačnih elemenata u programskom paketu Abaqus, a rezultati simulacije su se zatim
koristili za određivanje parametara materijala kako bi se to radilo da je umjesto simulacije
vršen eksperiment. Parametri su izračunati metodom najmanjih kvadrata pomoću računalnog
programa Octave. Nakon određivanja parametara materijala, procijenjena je greška
usporedbom izračunatih parametara sa parametrima zadanim u simulaciji te usporedbom
izračunatih naprezanja s naprezanjima koja proizlaze iz simulacije za odgovarajući režim
opterećenja.
Postupak je najprije verifikacijski proveden na jednostavnijem, neo-Hookeovom
materijalnom modelu, koji opisuje izotropno ponašanje hiperelastičnog materijala. Rezultati
postupka na neo-Hookeovom materijalnom modelu potvrđeni su rezultatima već izvršenog
eksperimenta.
Nakon verifikacije, postupak je proveden na anizotropnom, Holzapfel-Gasser-Ogden modelu,
razvijenom za opisivanje ponašanja arterija.

Abstract (english)

The aim of this paper is to examine the influence of prestressing during the biaxial tensile test
on the accuracy of determining the parameters of anisotropic material such as soft tissue or
3D printed polymers. First, a finite element method simulation was made in Abaqus software
package, results of which were then used to determine material parameters the way material
parameters would be determined from experiment. Parameters were calculated using least
squares method using computer program Octave. After determining material parameters, an
error was estimated by comparing calculated parameters with parameters used in simulation
and by comparing calculated stresses with simulated stresses for corresponding load mode.
The procedure was first verified on a simpler, neo-Hooke material model, which describes the
isotropic behavior of the hyperelastic material. The results of the procedure on the neo-Hooke
material model were confirmed by the results of the already performed experiment.
After verification, the procedure was performed on an anisotropic, Holzapfel-Gasser-Ogden
model, developed to describe the behavior of arteries.

• Keywords: dvoosni vlačni test; anizotropnost; hiperelastičnost; materijalni model; neoHooke; Holzapfel-Gasser-Ogden; metoda konačnih elemenata
• Keywords (english): biaxial tensile test; anisotropy; hyperelasticity; material model; neo-Hooke; Holzapfel-Gasser-Ogden; finite element method
• Language: croatian
• URN:NBN: urn:nbn:hr:235:936248
• Study programme: Title: Mechanical Engineering; specializations in: Design, Process and Energy Engineering, Production Engineering, Engineering Modelling and Computer Simulation, Marine Engineering, Industrial Engineering and Management, Materials Engineering; Course: Engineering Modelling and Computer Simulation; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-02-28 22:37:23