Ispitivanje utjecaja brzine opterećenja na lomno ponašanje sinteriranog čelika

master's thesis

• Title (english): Investigation of the loading rate influence on the fracture behaviour of sintered steel
• Author: Matea Minauf
• Mentor: Tomislav Lesičar (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2023-12-06, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; General Mechanical Engineering (Construction)

Abstract

Danas proces metalurgije praha pronalazi široku primjenu u različitim industrijama. Ona omogućuje proizvodnju novih materijala specifičnih i poboljšanih svojstava. Jedan od često korištenih materijala dobiven procesom metalurgije praha je sinterirani čelik. U ovom radu na temelju eksperimentalno dobivenih podataka prilikom provedbe monotonog vlačnog testa pri brzini opterećivanja od 1 mm/min provedeno je modeliranje konstitutivnog ponašanja materijala i određivanje parametara loma. Za tako definirane materijalne parametre, provedena je numerička analiza najprije u Abaqus/Standardu, a potom u Abaqus/Explicitu pri raznim brzinama opterećivanja. U prvom poglavlju opisan je proces dobivanja sinteriranog čelika i dana su svojstva sinteriranog čelika Astaloy Mo+0,2C. U drugom poglavlju opisana je metoda konačnih elemenata, objašnjene su eksplicitne metode vremenske integracije i opisani su korišteni konačni elementi. U trećem poglavlju opisano je elastoplastično ponašanje i očvršćenje materijala. Također su objašnjeni i materijalni modeli koji se koriste u numeričkim proračunima. U četvrtom poglavlju opisano je numeričko modeliranje inicijacije i rasta oštećenja. U petom poglavlju provedena je numerička simulacija vlačnog testa na epruvetama izrađenim od sinteriranog čelika triju različitih gustoća: 6,5 g/cm3, 6,8 g/cm3 i 7,1 g/cm3 te su dani rezultati utjecaja različitih brzina opterećivanja na lomno ponašanje sinteriranog čelika. Korištene brzine opterećivanja su: 1 mm/min, 2 mm/min, 5 mm/min i 10 mm/min. U šestom poglavlju dan je zaključak cijelog rada.

Abstract (english)

Today, the powder metallurgy process is widely applied in various industries. It provides the production of new materials with specific and improved properties. One of the frequently used materials obtained by the powder metallurgy process is sintered steel. In this thesis, based on the data obtained experimentally during the execution of the monotonic tensile test at a loading speed of 1 mm/min, the modeling of the constitutive behavior of the material and the determination of the fracture parameters were carried out. For the material parameters defined in this way, a numerical analysis was performed first in Abaqus/Standard and then in Abaqus/Explicit at various loading rates. In the first chapter, the process of obtaining sintered steel is described and the properties of sintered steel Astaloy Mo+0,2C are given. In the second chapter, the finite element method is described, explicit methods of time integration are explained and the finite elements used are described. In the third chapter, the elastoplastic behavior and hardening of the material is described. Also, material models used in numerical calculations are explained. The fourth chapter describes the numerical modeling of damage initiation and growth. In the fifth chapter, a numerical simulation of the tensile test was performed on test tubes made of sintered steel of three different densities: 6.5 g/cm3, 6.8 g/cm3 and 7.1 g/cm3, and the results of the influence of different loading rates on the fracture behavior of sintered steel were given. The loading speeds used are: 1 mm/min, 2 mm/min, 5 mm/min and 10 mm/min. The conclusion of the entire work is given in the sixth chapter.

• Keywords: metalurgija praha; sinterirani čelik; Abaqus/Standard; Abaqus/Explicit; elastoplastičnost; oštećenje; brzina opterećivanja
• Keywords (english): powder metallurgy; sintered steel; Abaqus/Standard; Abaqus/Explicit; elastoplasticity; damage; loading rate
• Language: croatian
• URN:NBN: urn:nbn:hr:235:729692
• 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: 2023-12-04 07:40:45