Aslan, Özgür
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Özgür, Aslan
Aslan O.
Ö.,Aslan
A., Ozgur
Aslan, Özgür
Aslan,O.
O.,Aslan
Ozgur, Aslan
Aslan, O.
A., Özgür
Aslan,Ö.
A.,Ozgur
Ö., Aslan
O., Aslan
Aslan Ö.
A.,Özgür
Aslan, Ozgur
Aslan O.
Ö.,Aslan
A., Ozgur
Aslan, Özgür
Aslan,O.
O.,Aslan
Ozgur, Aslan
Aslan, O.
A., Özgür
Aslan,Ö.
A.,Ozgur
Ö., Aslan
O., Aslan
Aslan Ö.
A.,Özgür
Aslan, Ozgur
Job Title
Profesor Doktor
Email Address
ozgur.aslan@atilim.edu.tr
Main Affiliation
Mechanical Engineering
Status
Website
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Sustainable Development Goals
7
AFFORDABLE AND CLEAN ENERGY

2
Research Products
8
DECENT WORK AND ECONOMIC GROWTH

1
Research Products
12
RESPONSIBLE CONSUMPTION AND PRODUCTION

1
Research Products
14
LIFE BELOW WATER

1
Research Products

Scholarly Output
27
Articles
13
Citation Count
67
Supervised Theses
3
27 results
Scholarly Output Search Results
Now showing 1 - 10 of 27
Article An Investigation of Recycled Rubber Composites Reinforced With Micro Glass Bubbles: an Experimental and Numerical Approach(Taylor & Francis Ltd, 2024) Kabakci, Gamze Cakir; Bayraktar, Emin; Aslan, Ozgur; Mechanical EngineeringRecycled rubber is widely used for its lightweight and cost-effective properties but often has limited mechanical strength, restricting its applications. This study enhances the mechanical performance of devulcanised recycled rubber by reinforcing it with micro glass bubbles (GBs) featuring a density of 0.65 g/cm(3) and an elastic modulus of 3.5 GPa, offering a high strength-to-density ratio. Uniaxial compression tests were conducted on samples with GB volume fractions of 5%, 10%, and 15%. Results were validated through finite element analysis (FEA) in ABAQUS/Standard, incorporating randomised GB distributions. A 2D representative volume element (RVE) with randomly distributed GBs was modelled, applying periodic boundary conditions to simplify the composite into an equivalent homogeneous material. Numerical simulations assessed the effects of GB diameters (30, 40, and 50 mu m) and inclusion size ranges (20-50 mu m and 10-60 mu m), finding minimal impact on results. The RVE, sized at 238 mu m, accurately represented macroscale composite behaviour. Stress-strain behaviour was analysed using average stress and strain tensors. The strong agreement between experimental and numerical results validates the proposed method, demonstrating its accuracy in predicting the mechanical behaviour of the reinforced composite material.Conference Object Citation - Scopus: 1Numerical Modeling of Recycled Rubber Based Composites Reinforced With Glass Fibers at High Strain Rates(Springer, 2022) K-Cakir,G.; Aslan,O.; Bayraktar,E.; Department of Basic English (Prep School); Mechanical EngineeringDue to its high impact energy absorption properties, devulcanized recycled rubber based composites can be considered as a low cost candidate material for military applications which require lightweight protection against shock waves. This work aims at modeling of low cost devulcanized recycled rubber based composite behavior at high strain rates. In that framework, we established a continuum-based material model in order to capture the macroscopic behavior of the recycled rubber based composite material and numerically reproduce the results from the basic characterization tests. The model is implemented for Finite Element Analysis Software ABAQUS/Standard as a user subroutine UMAT for implicit nonlinear finite element calculations in order to simulate the behavior of several RVEs representing the microstructure of the composite and it is behavior at high strain rates. © 2022, The Society for Experimental Mechanics.Article Citation - WoS: 4Citation - Scopus: 4A Large-Deformation Gradient Damage Model for Single Crystals Based on Microdamage Theory(Mdpi, 2020) Aslan, Ozgur; Bayraktar, Emin; Mechanical EngineeringThis work aims at the unification of the thermodynamically consistent representation of the micromorphic theory and the microdamage approach for the purpose of modeling crack growth and damage regularization in crystalline solids. In contrast to the thermodynamical representation of the microdamage theory, micromorphic contribution to flow resistance is defined in a dual fashion as energetic and dissipative in character, in order to bring certain clarity and consistency to the modeling aspects. The approach is further extended for large deformations and numerically implemented in a commercial finite element software. Specific numerical model problems are presented in order to demonstrate the ability of the approach to regularize anisotropic damage fields for large deformations and eliminate mesh dependency.Book Part Design of Recycled Aluminium (AA7075)-Based Composites Reinforced with Nano Filler NiAl Intermetallic and Nano Niobium Powder Produced with Vacuum Arc Melting for Aeronautical Applications(CRC Press, 2023) Kasar,C.; Aslan,O.; Gatamorta,F.; Miskioglu,I.; Bayraktar,E.; Department of Basic English (Prep School); Mechanical EngineeringIn the frame of the common research project, the mechanical properties of recycled gas atomized scrap aluminium (AA 7075)-based composites reinforced with nano filler NiAl intermetallic and niobium (Nb) elements have been evaluated. Firstly, the mixture was homogenized by means of a ball milling process for 4 hours. After cold compaction of the compositions, the final specimens have been produced with “vacuum arc melting” for aeronautical applications. Static and dynamic compression tests have been conducted. Additional tensile tests have also been carried out. Experimental results were compared with a finite element method. The interface and microstructure of these composites have also been evaluated by a scanning electron microscopy. © 2024 selection and editorial matter, N. M. Nurazzi, E. Bayraktar, M. N. F. Norrrahim, H. A. Aisyah, N. Abdullah, and M. R. M. Asyraf; individual chapters, the contributors.Article Citation - WoS: 1Citation - Scopus: 1Effect of Ti-V and Nb Addition on the Properties of Almg7cu1.2 Alloy(Springer Int Publ Ag, 2025) Gul, Armagan; Dispinar, Derya; Aslan, Ozgur; Mechanical EngineeringIn the development of aluminum casting alloys, considerable attention is given to the impact of various alloying elements, with numerous studies exploring how these elements influence the material's properties. However, the selection of alloying elements alone does not ensure optimal final quality. The casting process and melt treatment methods also play a critical role in achieving a defect-free structure, particularly when paired with defect characterization and final property assessment. Therefore, it is essential to investigate the interplay between alloying element choice, melt treatment, and defect evaluation in tandem. In this study, copper and magnesium main alloying elements have been chosen along with master alloys of Ti-V-Nb as grain refiners for the aluminum cast alloy. Phase formations have been investigated by simulated phase diagrams. Casting experiments have been done using a tilt pouring method into sand molds, and small bubble degassing equipment has been used to ensure the alloying and melt quality satisfying required mechanical strength. Composition and alloying have been validated by spectral analysis and XRF measurements. Microstructural analyses have been performed by both digital microscopy and scanning electron microscopy. EDS mappings have been carried out for alloying elements distributions. Internal defect distribution and defect structure have been evaluated by computed tomography (CT) scans. Both as-cast and heat-treated specimens have undergone tensile and hardness tests to characterize the mechanical behaviors. CT scans and mechanical behaviors have beencorrelated, and defect metrics have been investigated and classified according to defect surface, defect volumes and projected areas on XY-XZ-YZ planes. Contour maps of defect metrics and tensile properties have been analyzed to generate input to finite element simulations for latter stages studies, and correlation of strength-defect regressions has yielded parametric results to understand structural defects-mechanical performance relations. GTN and Beremin localization models capable of depicting material behavior in the presence of defects have been used to link the experimental and virtual validation assessments. In view of test results, a maximum of 0.125 wt% Nb content in AlMgCu-TiV alloy has been proposed having a tensile strength reaching 300 MPa-7.5% elongation at 0.75% Nb content with grain refinement effect owing to Al-Nb, Al-Ti, Al-V aluminide particles and good dispersion of Nb, Ti, V elements on the microstructure as assessed by EDS mapping. CT scan reconstruction images and metrics have successfully connected tensile strength and elongation with defect volume and defect surface area for the proposed alloy. In this context, the volume and surface area of defects have been evaluated as critical metrics in evaluating the mechanical properties of Al7MgCu1.2 cast alloys. Defect localization and failure point detection during plastic deformation zone have been demonstrated by Beremin model which can lead to future studies leveraging these metrics to validate material strength using damage models such as Gurson, GTN or Beremin for crack initiation and propagation methodologies.Book Part Design of Recycled Aluminium (aa 7075+aa1050 Fine Chips)-Based Composites Reinforced With Nano-Sic Whiskers, Fine Carbon Fiber for Aeronautical Applications(CRC Press, 2023) Aslan,O.; Klinkova,O.; Katundi,D.; Miskioglu,I.; Bayraktar,E.; Department of Basic English (Prep School); Mechanical EngineeringIn the frame of the research project that is going on, the mechanical properties of recycled gas atomized scrap aluminium (AA7075) based hybrid composites reinforced with nano SiC filler (whisker)+ Graphene Nano plateless (GNP) and fine carbon Fibers elements have been evaluated. Firstly, the mixture was homogenized by means of ball milling process during 4 hours. After hot compaction at 200°C compaction of the compositions the final specimens have been produced with the novel combined method called “SINTER+FORGING” at 650°C followed by relaxation treatment at 200°C during the 2 hours. This type of hybrid composite is used for aeronautical applications. Static and dynamic-Time dependent compression tests have been conducted. Interface and microstructure of these composites have also been evaluated by Scanning Electron Microscope (SEM). © 2024 selection and editorial matter, N. M. Nurazzi, E. Bayraktar, M. N. F. Norrrahim, H. A. Aisyah, N. Abdullah, and M. R. M. Asyraf; individual chapters, the contributors.Article Citation - WoS: 5Citation - Scopus: 6Toughening Mechanism Analysis of Recycled Rubber-Based Composites Reinforced With Glass Bubbles, Glass Fibers and Alumina Fibers(Mdpi, 2021) Kabakci, Gamze Cakir; Aslan, Ozgur; Bayraktar, Emin; Mechanical EngineeringRecycling of materials attracts considerable attention around the world due to environmental and economic concerns. Recycled rubber is one of the most commonly used recyclable materials in a number of industries, including automotive and aeronautic because of their low weight and cost efficiency. In this research, devulcanized recycled rubber-based composites are designed with glass bubble microsphere, short glass fiber, aluminum chip and fine gamma alumina fiber (gamma-Al2O3) reinforcements. After the determination of the reinforcements with matrix, bending strength and fracture characteristics of the composite are investigated by three-point bending (3PB) tests. Halpin-Tsai homogenization model is adapted to the rubber-based composites to estimate the moduli of the composites. Furthermore, the relevant toughening mechanisms for the most suitable reinforcements are analyzed and stress intensity factor, K-Ic and critical energy release rate, G(Ic) in mode I are determined by 3PB test with single edge notch specimens. In addition, 3PB tests are simulated by finite element analysis and the results are compared with the experimental results. Microstructural and fracture surfaces analysis are carried out by means of scanning electron microscopy (SEM). Mechanical test results show that the reinforcement with glass bubbles, aluminum oxide ceramic fibers and aluminum chips generally increase the fracture toughness of the composites.Article Citation - Scopus: 1Analytical Solutions of Model Problems for Large-Deformation Micromorphic Approach To Gradient Plasticity(Mdpi, 2021) Aslan, Ozgur; Bayraktar, Emin; Mechanical EngineeringThe objective of this work is to present analytical solutions for several 2D model problems to demonstrate the unique plastic fields generated by the implementation of micromorphic approach for gradient plasticity. The approach is presented for finite deformations and several macroscopic and nonstandard microscopic boundary conditions are applied to a gliding plate to illustrate the capability to predict the size effects and inhomogeneous plastic fields promoted by the gradient terms. The constitutive behavior of the material undergoing plastic deformation is analyzed for softening, hardening and perfect plastic response and corresponding solutions are provided. The analytical solutions are also shown to match with the numerical results obtained by implementing a user element subroutine (UEL) to the commercial finite element software Abaqus/Standard.Conference Object Citation - Scopus: 2Toughening Mechanism of Silicon Whiskers and Alumina Fibres (γ-Al2o3) Reinforced Ni-Al Matrix Composites Through “sintering + Forging”(Springer, 2023) Miskioglu,I.; Zambelis,G.; Gatamorta,F.; Aslan,O.; Bayraktar,E.; Department of Basic English (Prep School); Mechanical EngineeringIn this study, the microstructural formation and static/dynamic compression behaviour of recycled Ni-Al-Cu matrix hybrid composites reinforced with silicon whiskers and alumina (Al2O3) fibres will be studied. It is intended to be an alternative to traditional alloys/composites used in the aeronautical industry. These composites generally are produced using by combined “sintering + forging” processes. The static and dynamic properties will be evaluated in detail, considering the relevant scanning electron microscopy (SEM) microstructures (including the distribution of reinforcement elements). © 2023, The Society for Experimental Mechanics, Inc.Conference Object Citation - WoS: 14Citation - Scopus: 16Numerical Modeling of Hydrogen Diffusion in Metals Accounting for Large Deformations(Pergamon-elsevier Science Ltd, 2015) Aslan, Ozgur; Mechanical EngineeringWhile the deleterious effects of hydrogen on metals and alloys are well known, the precise role of hydrogen in the underlying microscopic mechanisms is still not well understood and as of yet, the modeling attempts on hydrogen embrittlement and hydrogen induced cracking have not led to a proper method for life-time prediction. This work aims at the development of a robust numerical strategy in order to solve the non-linear coupled problem presented in the work of Anand [1]. The numerical implementation is performed for finite element method and the analysis are done to address the issue of hydrogen transport and hydrogen-embrittlement-related failures in metals. Specifically, problems related to the mechanism of hydrogen enhanced localized plasticity (HELP) is studied and macroscale shear localization phenomenon resulting from hydrogen induced material softening is considered at the phenomenological level. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
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