Analiza vojne kacige prilikom udara projektila

Sviličić, Šimun (2017) Analiza vojne kacige prilikom udara projektila. = Tactical helmet impact analysis. Master's thesis (Bologna) , Sveučilište u Zagrebu, Fakultet strojarstva i brodogradnje, UNSPECIFIED. Mentor: Skozrit, Ivica.

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Abstract (Croatian)

U radu se daje kratak pregled o projektilima, vojnoj kacigi, samoj prirodi udara te balistici, s naglaskom na terminalnu balistiku. U drugome poglavlju razrađuje se eksplicitna analiza, temelji eksplicitne analize, način kako je implementirana u programski paket, različite tehnike koje program nudi u svrhu smanjenja računalnog vremena i stabilnosti rješenja. Treće poglavlje opisuje dostupne materijalne modele u programskome paketu, naznačuje odabrani materijalni model te problematiku materijalnog modela, njegove prednosti, način kako je implementiran u Abaqus/Explicit te poteškoće implementacije. Također, razmatraju se različiti pristupi rješavanja problema, koristeći različite konačne elemente, i navode se prednosti i nedostaci istih. Peto poglavlje daje uvid u razliku između implicitnog i eksplicitnog načina rješavanja problema, kao i njihove prednosti i nedostatke. Točnost rješenja eksplicitnim pristupom prikazana je u šestome poglavlju usporedbom analitičkog rješenja udara mase u gredu s numeričkim rješenjem dobivenim pomoću Abaqus/Explicit. Validacija konačnih elemenata provedena je u sedmome poglavlju gdje se vrši niz simulacija s različitim vrstama konačnih elemenata kako bi se uvidio optimalniji pristup problemu kroz vrijeme, točnost rezultata i samu stabilnost analize. U osmome poglavlju razmatra se sam problem s kompleksnom geometrijom kacige, uzima se u obzir više tipova zrna kako bi se uvidjele razlike između njih. Vrše se simulacije s različitim tipovima zrna, različitim brzinama udara zrna u kacigu i različitim materijalom iz četiri položaja.

Abstract

This thesis consists of nine chapters. First, there is a short introduction into the field of terminal ballistics, projectiles, criteria for classifying ballistic impact and impact analysis. In second chapter, explicit analysis is described, as well as theory of it, the way it is implemented in software, different software tehniques for time scaling and analysis stability. Third chapter gives overview of existing material models available in literature and more detailed overview of material model that has been used in this work. It is described why this material model is used in the work, what are advantages and disadvantages of the model and how it is implemented in Abaqus/Explicit. Also, different finite elements are shown and described. After that, in fifth chapter, difference between implicit and explicit analysis is explained. Validation of Abaqus/Explicit is shown in sixth chapter by comparing analytical results of mass on beam impact with numerical results. Validation of explicit finite elements is presented in chapter seven. Different finite elements where used in analysis to determine running time and result convergence of analysis for those elements. In chapter eight there is intro into the main problem of analysis, simplification of complex geometry, different projectiles with different velocities and under four different angles.

Item Type: Thesis (Master's thesis (Bologna))
Uncontrolled Keywords: eksplicitna numerička analiza, metoda konačnih elemenata, analiza udara, kaciga, zrno, metak, Johnson-Cook model
Keywords (Croatian): explicit numerical analysis, finite elements method, ballistic impacts, helmet, bullet, material model, projectile, Johnson-Cook model
Subjects: TECHNICAL SCIENCE > Mechanical Engineering
Divisions: 200 Department of Engineering Mechanics > 210 Chair of Mechanics and Strength of Materials
Date Deposited: 30 Nov 2017 09:56
Last Modified: 30 Nov 2019 05:36
URI: http://repozitorij.fsb.hr/id/eprint/8149

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