magistrsko delo
Žiga Veronek (Author), Matej Vesenjak (Mentor), Matej Borovinšek (Co-mentor)

Abstract

Cilj naloge je inverzna določitev materialnih parametrov zaprto-celične aluminijeve pene, ki bodo omogočili natančnejšo in učinkovitejšo izvedbo računalniških simulacij s homogeniziranim modelom porušljive pene. Materialne parametre smo določili na podlagi eksperimentalnih rezultatov enoosnega tlačnega in tritočkovnega upogibnega preizkusa, ki so primerjani z rezultati enakega preizkusa v virtualnem okolju (simulacije). Uporabili smo F-d diagram (reakcijska sila-pomik) iz eksperimenta in ga primerjali z F-d diagramom iz simulacije. Inverzno določitev materialnih parametrov smo izvedli z matematično optimizacijo. Uporabili smo dva optimizacijska algoritma in sicer Nelder-Mead (Simplex) metodo in genetski algoritem. Uspešno smo izvedli inverzno določitev materialnih parametrov z optimizacijo na podlagi tlačnega preizkusa. Povprečno odstopanje reakcijskih sil simulacije in eksperimenta je znašalo 0,176 kN oziroma 1,2 %. Z dobljenimi materialnimi podatki smo zagnali simulacijo upogibnega preizkusa in primerjali reakcijsko silo z reakcijsko silo eksperimenta. Rezultati se niso ujemali. Ugotovili smo, da samo optimizacija materialnih parametrov aluminijeve pene na podlagi tlačnega preizkusa ni dovolj za pravilno določitev le teh. Na podlagi česar smo nato sestavili vezan optimizacijski model, ki je vseboval zaporedno vezani simulaciji tlaka in upogiba. Rezultat tega optimizacijskega modela daje natančnejše ujemanje reakcijskih sil simulacije in eksperimenta tlačnega, kot tudi upogibnega preizkusa. Normirano odstopanje vezanega modela znaša 14,7 %. Kjer znaša normirano odstopanje tlaka 17,6 % in upogiba 11,7 %. Ugotovili smo, da je možno z vezano optimizacijo pridobiti materialne parametre aluminijeve pene s katerimi, lahko z zadovoljivim odstopanjem simuliramo obnašanje materiala pri mehanskih obremenitvah.

Keywords

kovinske pene;enoosni tlačni testi;tritočkovni upogibni testi;optimizacija;metoda končnih elemntov;materialni model porušljive pene;inverzna določitev materialnih parametrov;magistrske naloge;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UM FS - Faculty of Mechanical Engineering
Publisher: [Ž. Veronek]
UDC: [620.173/.174:621.762]:519.876.5(043.2)
COBISS: 19549206 Link will open in a new window
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Other data

Secondary language: English
Secondary title: Inverse determination of closed - cell foam material parameters at compression and bending load
Secondary abstract: The goal of this thesis is to determine the material parameters of closed-cell aluminum foam, which will enable accurate simulations using crushable foam material model, with inverse engineering. Material parameters were determined based on experimental data from uniaxial compression and three-point bending tests, which were compared with data acquired from simulations of the same tests. The experimental reaction force data were compared with that of the simulations, from which average deviation was calculated. Mathematical optimization was used to determine the material parameters with inverse engineering. Two optimization algorithms were used genetic algorithm and Nelder-Mead (Simplex) method. Inverse determination of material parameters based on compression tests was successful. Average deviation of experimental and simulated reaction forces was 0,176 kN or 1,2 %. With the same material parameters we simulated the bending test and compared the reaction force with the experimental data. The acquired numerical results were not in agreement with experimental results. We realized that optimization of material parameters based on compression test alone, is not enough for their accurate determination. Based on this conclusion, we constructed a new optimization model with interaction between the compression and bending test. This optimization model gives better results at compression and bending load. Achieved normalized deviation is 14,7 %, where normalized deviation of compression and bending are 17,6 % and 11,7 %, respectively. We concluded, that the optimization model with interaction between the compression and bending tests provides material parameters, that are able to accurately simulate behavior of material under different mechanical loading conditions.
Secondary keywords: metal foam;uniaxial compression test;three-point bending test;optimization;finite element analysis;crushable foam material model;inverse determination of material parameters;
URN: URN:SI:UM:
Type (COBISS): Master's thesis/paper
Thesis comment: Univ. v Mariboru, Fak. za strojništvo
Pages: VIII, 45 f.
ID: 9129010