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Tanoğlu, Metin

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Tanoğlu M.
Tanoglu, Metin
Tanoğlu, Metin
Tanoglu, M.
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Prof. Dr.
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metintanoglu@iyte.edu.tr
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Makina Mühendisliği Bölümü
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Sustainable Development Goals

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Scholarly Output

74

Articles

32

Citation Count

0

Supervised Theses

41

Scholarly Output Search Results

Now showing 1 - 10 of 73
  • Article
    Temperature dependence of electrical conductivity in double-wall and multi-wall carbon nanotube/polyester nanocomposites
    (Springer, 2007) Simsek, Yilmaz; Ozyuzer, Lutfi; Seyhan, A. Tugrul; Tanoglu, Metin; Schulte, Karl; Tanoğlu, Metin
    The aim of this study is to investigate temperature dependence of electrical conductivity of carbon nanotube (CNT)/polyester nanocomposites from room temperature to 77 K using four-point probe test method. To produce nanocomposites, various types and amounts of CNTs (0.1, 0.3 and 0.5 wt.%) were dispersed via 3-roll mill technique within a specially formulized resin blend of thermoset polyesters. CNTs used in the study include multi walled carbon nanotubes (MWCNT) and double-walled carbon nanotubes (DWCNT) with and without amine functional groups (-NH2). It was observed that the incorporation of carbon nanotubes into resin blend yields electrically percolating networks and electrical conductivity of the resulting nanocomposites increases with increasing amount of nanotubes. However, nanocomposites containing amino functionalized carbon nanotubes exhibit relatively lower electrical conductivity compared to those with non-functionalized carbon nanotubes. To get better interpretation of the mechanism leading to conductive network via CNTs with and without amine functional groups, the experimental results were fitted to fluctuation-induced tunneling through the barriers between the metallic regions model. It was found that the results are in good agreement with prediction of proposed model.
  • Master Thesis
    Development of carbon black-layered clay/epoxy nanocomposites
    (Izmir Institute of Technology, 2008) Pekşen Özer, Bahar Başak; Tanoğlu, Metin; Tanoğlu, Metin
    In this study, a novel epoxy nanocomposite with electrical conductivity and having improved mechanical and thermal properties was synthesized. Carbon black/ epoxy composites and carbon black-layered clay/epoxy nanocomposites were prepared by mixing via 3-roll mill. The first type of the composite was produced to determine the percolation threshold concentration (Vc). The second type with constant carbon black concentration, slightly over Vc, was synthesized to investigate the influence of clay content on the thermal, mechanical, electrical and structural properties of nanocomposites. Carbon black used in the study was extra conductive filler with 30 nm spherical particles. Layered clay was Na+ Montmorillonite treated with ditallow dimethlyamine to assure better intercalation within the epoxy resin. Vc value was determined to be 0.2 vol% and 0.25 vol% carbon black was added together with varying clay contents to the epoxy system to produce nanocomposites. Only the nanocomposites with 0.5 vol. % clay loading showed electrical conductivity. However, the composites with higher clay loadings showed insulating behaviour due to hindrance of carbon black network by clay layers. According to the XRD results, nanocomposites exhibited some extent of exfoliation. It was found that tensile modulus values of the epoxy increased;however flexural modulus values remained constant, with increasing clay content.Elastic modulus of neat epoxy (3.7 GPa) was increased about 28 % with 0.5 vol% clay addition. Thermomechanical analysis results revealed that the storage modulus, glass transition temperature and initial degradation temperature of epoxy was slightly enhanced due to clay loading.
  • Master Thesis
    Development of layered silicate/epoxy nanocomposite
    (Izmir Institute of Technology, 2006) Kaya, Elçin Dilek; Tanoğlu, Metin; Tanoğlu, Metin
    Layered silicate/polymer nanocomposites are materials that display rather unique properties, even at low silicate content, by comparison with more conventional particulate-filled polymers. These nanocomposites exhibit improved mechanical, thermal, optical, gas permeability resistance and fire retardancy properties when compared with the pure polymer.In this study, layered silicate/polymer nanocomposites were prepared using Na+ cation containing montmorillonite (MMT) and epoxy resins. Silicate particles were treated with hexadecyltrimethylammonium chloride (HTAC) to obtain the complete homogenous dispersion of the nano plaques within the polymer matrix which forms the exfoliated microstructure. In this way, organophilic silicates (OMMT) were obtained.Modification of the silicate expands the silicate galleries (from 14 to 18 )that promote the formation of exfoliated composite structure. SEM results showed that nanocomposites with organically modified MMT exhibited better dispersion than those with MMT. It was found that the tensile and flexural modulus values are increased, whereas the fracture toughness is decreased with increasing silicate content. Thermal analysis results revealed that the glass transition temperature(Tg) of the neat epoxy resin (63.6oC) increases to 68.9 oC for the nanocomposites with 3 wt. % of OMMT. By incorporation of silicate particles, the dynamic mechanical properties of epoxy; including the storage and loss modulus and Tg are increased. Optical transmission values of the epoxy were affected by MMT and OMMT silicate incorporation. It was found that flame resistance at the polymer improved by the incorporation of MMT particles to the neat epoxy.
  • Doctoral Thesis
    Toughening of carbon fiber based composites with electrospun fabric layers
    (Izmir Institute of Technology, 2017-11) Beylergil, Bertan; Tanoğlu, Metin; Tanoğlu, Metin; Aktaş, Engin
    The objective of this PhD thesis is to investigate interlaminar Mode-I fracture toughness of carbon fiber/epoxy composites interleaved by micro and/or nano scaled PA66 nonwoven veils. Also, the effects of electrospun PVA nanofibers on the mechanical performance of these composites were investigated. Additionally, this thesis also deals with the effects of aramid nonwoven veils on the mechanical properties of CF/EP composites. The produced nanofibers produced by electrospinning were directly deposited on carbon fiber fabrics. Then, reference and nano-modified laminates were manufactured by vacuum infusion method. A series of mechanical tests such as tensile, compression, three point bending, Charpy-impact, interlaminar shear strength and open hole tensile tests (OHT) were carried out on the prepared specimens. Double cantilever beam (DCB) tests were conducted on reference and interleaf-modified laminates. The effect of PA 66 nanofiber areal weight density was also evaluated with varying electrospinning time. Scanning electron microscopy (SEM) was used to investigate the fiber morphology and to understand the toughening mechanisms. Dynamic mechanic analysis (DMA) was used to investigate the thermo-mechanical behavior of reference and interleaf-modified composite specimens. Differential scanning calorimetry (DSC) was used to determine the thermal properties of micro and electrospun PA66 nonwoven veils. Comparing the mechanical test results, the most effective nonwoven interleaving system was determined in terms of higher delamination resistance and in-plane mechanical properties. Finite element method (FEM) was used to evaluate the effects of electrospun PA66 nonwoven veils on the CF/EP composites. Numerical simulations of Mode-I fracture toughness tests were carried out using ANSYS Workbench. The results showed that the most effective material was electrospun PA66 nonwovens considering the higher delamination resistance. Additionally, the electrospun PA 66 nonwovens also improved Charpy-impact and interlaminar shear strength of the reference CF/EP composites. Numerical results showed good agreement with the experimental ones.
  • Master Thesis
    Investigation of environmental durability of carbon fiber/epoxy composites
    (Izmir Institute of Technology, 2013) Yağmur, Samet; Tanoğlu, Metin; Tanoğlu, Metin
    Fiber reinforced polymer composites, that have increasing demand in many applications such as aircraft and automotive industry, are usually exposed to different environmental conditions which may be harmful to them. The investigation of their environmental durability is critical for those applications. The objective of this study was to investigate the effects of temperature and moisture on durability of carbon fiber reinforced epoxy composites. For this purpose, 0/90° woven, plain unidirectional and non-crimp biaxial ±45 fabrics were used as reinforcement. The specimens were manufactured using vacuum resin infusion process to obtain relatively high fibre volume fraction ratios. The composites manufactured were exposed to cyclic aging conditions to simulate aircraft flight environment. Hygrothermal, high temperature and freezing conditions were used as in one cycle which was 12 hours long. Moisture absorption was determined by weighing the specimens at regular intervals as a function of aging cycles. Tensile and flexural tests were performed prior to aging and after 500, 1000 and 1500 hours aging. After the completion of aging cycles, the moisture content did not increase significantly due to presence of subzero and high temperatures in aging cycles. The mechanical test results revealed differences based on the fabric types used. It was found that the tensile strength and modulus values of woven composites increased after aging cycles as compared to those of unidirectional and biaxial composites. On the other hand, flexural properties decreased at the end of the aging cycles for the composites aged as test coupons.
  • Master Thesis
    Improving mechanical properties of adhesive joints in carbon fiber reinforced polymer composites by incorporation of graphene added electrospun polymeric nanofibers
    (01. Izmir Institute of Technology, 2023-07) Yeke, Melisa; Tanoğlu, Metin; Tanoğlu, Metin
    Since composites joined with mechanical fasteners cause severe delamination damage, stress concentration in the joint area, and weight increase, joining composite materials with innovative methods have recently gained more importance. These joining methods prevent delamination damage, provide a uniform distribution of stress, and do not cause considerable weight increases. However, modifying the surface of composite parts joined by innovative methods is critical. In this study, the bonding surface was modified by coating carbon/epoxy prepregs with electrospun nanofibers with 10% wt/v ratio of PA 66 and 1%, 2% and 3% wt/v ratio of rGO added. Composite parts were joined in the hot press by the secondary bonding method using 3 plies of FM 300K film adhesive. The morphological structure of nanofibers and the dispersion of rGO were analyzed by SEM. The thermal properties of nanofibers were analyzed by DSC. The contact angle measurement device was used to determine the hydrophilic and hydrophobic properties of the unmodified prepreg and nanofiber-modified prepreg surface. The most hydrophilic surface was observed on the nanofiber-coated surface with 2% rGO added. Single Lap Joints (SLJ), and Charpy Impact tests were performed to examine the mechanical properties of modified and unmodified composite plates. According to the SLJ and Charpy Impact results, an improvement of 17.89% and 30.59% was observed in carbon/epoxy composite plates whose surface was modified with 2% rGO, respectively.
  • Master Thesis
    Investigation of mechanical properties and fatigue performance of carbon-glass fiber reinforced epxy hybrid composites
    (Izmir Institute of Technology, 2019-12) Sandallı, Hatice; Tanoğlu, Metin; Tanoğlu, Metin
    Recently, hybrid composites have known as high performance engineering materials and they have been used broadly in engineering applications where high strength to weight ratio, reasonable cost and ease of fabrication are requested. Since these composites offer combination of benefits of different kinds of fibers, their usage is increasing day after day. The objective of this thesis is to examine the mechanical properties of carbonglass fiber reinforced epoxy hybrid composites in two different configurations. Also, the fatigue performance under bending tests of these composites were investigated. The hybrid composites were manufactured by using vacuum infusion technique at ambient temperature. To examine the mechanical properties of manufactured composites, a series of mechanical tests such as compression, tensile and three-point bending tests were performed on the samples which were prepared in accordance with the relevant ASTM standards. Load-controlled three-point bending fatigue tests were also carried out to investigate the performance of manufactured composites under fatigue. The fatigue tests were performed at different stress levels varied from 30 percent to 90 percent of average ultimate flexural strength of the samples which were determined from static three-point bending tests. Subsequently stiffness loss and Wöhler curves were constructed using a specific failure criterion.
  • Article
    Silicon oxycarbide-based composites produced from pyrolysis of polysiloxanes with active Ti filler
    (Elsevier Sci Ltd, 2006) Akkas, H. Deniz; Ovecoglu, M. Lutfi; Tanoglu, Metin; Tanoğlu, Metin
    Phenyl (PPS) and methyl (PMS) containing polysiloxanes were pyrolyzed at elevated temperatures (900-1500 degrees C) under argon atmosphere to investigate the phase developments within the polymers. It was found that pyrolysis of the polymers under inert atmosphere up to 1300 degrees C leads to amorphous silicon oxycarbide (SiOxCy) ceramics. Conversions at higher temperatures results in the transformations into the crystalline beta-SiC phases. Ceramic matrix composites (CMCs) were developed based on the active filler controlled pyrolysis (AFCOP) of polysiloxanes with active Ti filler additions. CMC monoliths were prepared with 60-80 wt.% of active Ti particulates blended into polymer precursors. Green bodies of the composites were made by warm pressing under 15 MPa pressure and ceramics were obtained by pyrolysis at elevated temperatures between 900 and 1500 degrees C under argon atmosphere. The results showed that due to the incorporation of active Ti fillers, formation of crystalline phases such as TiC, TiSi, and TiO occured within the amorphous matrix due to the reactions between the Ti and the polymer decomposition products. The microstructural and mechanical characterization results of the composites are presented within the paper. (c) 2005 Elsevier Ltd. All rights reserved.
  • Article
    Determination of activation energy for carbon/epoxy prepregs containing carbon nanotubes by differential scanning calorimetry
    (Sage Publications Ltd, 2023) Uz, Yusuf Can; Tanoglu, Metin; Tanoğlu, Metin
    The aim of the present study is the thermal characterization of laboratory-scale carbon fiber/epoxy-based prepregs by incorporating single-wall carbon nanotubes (SWCNTs). Investigation of the cure behavior of a prepreg system is crucial for the characterization and optimization of the fiber reinforced polymeric (FRP) composite. To affect dispersion characteristics, SWCNTs were functionalized by oxidizing their surface with carboxyl (-COOH) group using an acid treatment. The modified resin system contained 0.05, 0.1, and 0.2 wt. % functionalized SWCNTs (F-SWCNTs). Carbon fiber (CF) reinforced prepregs containing various amount of F-SWCNTs were prepared using drum-type winding technique. FTIR was performed to identify new bonding groups formed after the functionalization of SWCNTs. Cure kinetics of prepregs prepared with/without F-SWCNTs were investigated using isoconversional methods.
  • Article
    Mechanical and energy absorption behaviors of metal/polymer layered sandwich structures
    (Sage Publications Ltd, 2011) Basturk, S. Bahar; Tanoglu, Metin; Tanoğlu, Metin
    This article considers the sandwich structures with aluminium (Al) foams of various thicknesses in conjunction with skins composed of fibre-metal laminates (FML). The FMLs with Al sheet and glass fiber reinforced polypropylene (GFPP) composites were integrated with Al foam for composing the sandwich panels. The FML-foam sandwich systems were manufactured by hot pressing in a mold at 200 degrees C under 1.5 MPa pressure. The bonding between the components of the sandwich was achieved by various surface modification techniques, i.e., silane surface treatment, PP adhesive film additition, and their combination. The Al sheet/Al foam sandwiches were also prepared by bonding the components with an epoxy adhesive for comparing the effect of GFPP on the mechanical performance of the sandwich structures. The energy absorption capacities together with compressive mechanical behavior of both Al foams and FML-foam sandwich systems were evaluated by flatwise compression tests. Experiments were performed on samples of varying foam thicknesses.