Person: KARAHAN, MEHMET
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KARAHAN
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MEHMET
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Publication Low velocity impact behaviour of aramid and uhmwpe composites(Inst Chemical Fibres, 2015-05-01) Karahan, Mehmet; Yıldırım, Kenan; KARAHAN, MEHMET; Mühendislik Mimarlık Fakültesi; Tekstil Mühendisliği Bölümü; 0000-0003-3915-5598; AAK-4298-2021The most popular method to produce composites for ballistic applications is to use aramid and ultra high molecular weight polyethylene (UHMWPE) fibers as reinforcement materials in different matrices. The composite materials used in this type of application, especially those used as armoring materials for explosions, are subjected to a very high level of energy. In this study, the effect of the reinforcement material type and cross-plied condition of reinforcement were examined using high-level impact tests. The impact tests were performed at low speed but high energy, and thus the behaviour of the composite materials that were exposed to high-level impact energy could be examined. According to the results, the UD aramid composite produced the best results with respect to high-level impact tests. In addition, mass optimisation could be achieved without the loss of the high-level impact energy by preparing a hybrid composite with UD UHMWPE and UD aramid fibers.Publication Fatigue behavior of carbon/epoxy composites reinforced with 3-dimensional woven fabric(Pamukkale Univ, 2013-01-01) Lomov, Stepan, V; Bogdanovich, Alexander E.; Verpoest, Ignaas; Karahan, Mehmet; KARAHAN, MEHMET; Teknik Bilimler Meslek Yüksekokulu; 0000-0003-3915-5598; 0000-0002-8194-4913; AAK-4298-2021; F-4031-2018This paper reports results of study of fatigue behavior of a non-crimp 3-dimensional woven carbon/epoxy composite in tension-tension fatigue. Infinite fatigue life limit corresponds to the load of 27.5 kN for fill direction. The damage under fatigue loading starts and develops from intersection of z-yarns and fill yarns. Since the z-yarns bonded the yarn layers, it is not seen the delaminastion damages. This indicate that for load carrying capacity and stiffness of 3-dimensional composites better than classic 2-dimensional textile composites.Publication Optimization of knitted fabrics for better thermo-physiological comfort by using taguchi-based principal component analysis(Univ Ljubljana, 2023-02-06) Kazmi, Kashaf; Javed, Zafar; Salman, Muhammad; Iftikhar, Fatima; Ahmed, Naseer; Naeem, Jawad; Jabbar, Abdul; Naeem, M. Salman; Karahan, Mehmet; KARAHAN, MEHMET; Teknik Bilimler Meslek Yüksekokulu; AAK-4298-2021The water, air permeability and thermal resistance of fabrics are important attributes that have a significant impact on the thermal comfort properties of sportswear fabrics in different environmental conditions. In this work, terry and fleece fabrics were developed by varying the fibre content and mass per unit area of fabrics. Moreover, the thermo-physical properties of the developed fabrics, including air permeability, water vapor permeability and thermal resistance, were analysed before and after washing. The multi-response optimization of the thermal comfort properties of knitted fabrics was performed using principal component analysis (PCA) and the Taguchi signal-to-noise ratio (PCA-S/N ratio) to achieve optimal properties. It was determined that the selected parameters (fabric type, finishing, fibre content and fabric mass per unit area) had a significant effect on the thermal comfort properties of knitted fabrics. The PCA analysis showed that 100% cotton terry fabric before washing with an aerial weight of 220 g/m(2) had higher air and water vapor permeability value, but a lower thermal resistance value.Publication Influence of chemical treatments and nanocellulose spray coating on the mechanical, low velocity impact and compression after impact performance of nonwoven jute composites(Taylor, 2019-04-11) Jabbar, Abdul; Hussain, Jown; Basit, Abdul; Naeem, M. Salman; Javaid, M. Usman; Karahan, Mehmet; Nazir, Ahsan; KARAHAN, MEHMET; Teknik Bilimler Meslek Yüksekokulu; AAK-4298-2021This paper reports the preparation and characterization of nonwoven jute composites. The untreated and chemically treated waste jute fibers were used to prepare needlepunched nonwoven fabrics. The treated waste jute fibers were also used to extract nanocellulose by pulverization, followed by acid hydrolysis. The prepared 2 wt% suspension of nanocellulose was spray coated over chemically treated nonwoven jute fabric. Afterward, the composites were prepared by compression molding technique. The surface morphologies of treated jute fibers and nanocellulose were characterized by scanning electron microscopy. The crystallinity of chemically treated jute fibers and nanocellulose was measured by X-ray diffraction. The effect of chemical treatments and nanocellulose spray coating over nonwoven jute reinforcement on the tensile, flexural, drop weight impact, and compression after impact properties of prepared composites has been investigated. The results revealed the improvement in mechanical properties after chemical treatments and nanocellulose coating. The overall better results were shown by composite sample prepared from chemically treated followed by nanocellulose sprayed jute nonwoven reinforcement.Publication Development of anti-bacterial and anti-viral nonwoven surgical masks for medical applications(Univ Ljubljani, 2022-06-14) Ahrari, Mazyar; Karahan, Mehmet; Hussain, Muzzamal; Nawab, Yasir; Khan, Asfandyar; Shirazi, Amir Abbas; Ahrari, Mazyar; KARAHAN, MEHMET; Mühendislik Fakültesi; Tekstil Mühendisliği Bölümü; AAK-4298-2021; AEL-5372-2022This article aims to investigate the development of surgical masks for medical applications by incorporating biocidal silver nanoparticles. Medical masks were developed in three layers of a nonwoven fabric, where the outer and inner layers were made of a spun-bond polypropylene nonwoven fabric and the middle layer consisted of a melt-blown nonwoven polypropylene fabric. In this study, silver nanoparticles in the concentrations of 1-5% were applied to masks with the pad-dry-cure method. The samples were cured at room temperature and subsequently examined for antimicrobial properties. Scanning electron microscopy, energy dispersive spectroscopy and Fourier transform infrared spectroscopy were used to investigate the morphological characteristics and chemical composition of the samples. Microbial cleanliness, bacterial filtration efficiency, antiviral effect and breathability tests were performed according to standard test protocols. The results revealed that the application of silver nanoparticles to a three-layer mask rendered the end product with outstanding antimicrobial and antiviral properties with poor breathability (air permeability) results.Publication Comparison of the mechanical properties of chopped glass, carbon, and aramid fiber reinforced polypropylene(Sage Publications, 2022-05-01) Arı, Ali; Bayram, Ali; Karahan, Mehmet; Karagöz, Secgin; BAYRAM, ALİ; KARAHAN, MEHMET; Mühendislik Fakültesi; Tekstil Bölümü; 0000-0003-3915-5598; AAK-4298-2021; GZC-1297-2022In this work, a comparative assessment of the mechanical properties of chopped glass-carbon-aramid fiber reinforced polypropylene (PP) composites was carried out. Reinforcement and matrix materials were mixed with the extrusion method, and then composite materials were produced in the form of plates with the press molding technique. The composites' tensile, 3-point bending, and drop weight tests were carried out and the surface morphology of the fractured surfaces was examined by Scanning Electron Microscope (SEM). The tests' results indicate that the mechanical properties increase significantly in the presence of fiber. On the other hand, it is observed that the effect in percentage decreases as the fiber content increases. Moreover, It was observed that some of the fiber materials were pulled out from the matrix as a result of stress. ANOVA analysis using S/N values, and F-Test were performed to observe the effectiveness of each test factor (fiber type, and fiber additive content) on the test results. Finally, an optimization study was carried out to obtain the mathematical expression by fitting the experimental data.Publication Evaluation of the mechanical properties of chopped carbon fibre reinforced polypropylene, polyethylene, polyamide 6, and polyamide 12 composites(Inst Natl Cercetare-dezvoltare Textile Pielarie-bucuresti, 2023-01-01) Ari, Ali; Karagoz, Secgin; Bayram, Ali; BAYRAM, ALİ; Karahan, Mehmet; KARAHAN, MEHMET; Mühendislik Fakültesi; Makina Mühendisliği Bölümü; 0000-0003-3915-5598; 0000-0002-0061-1755; AAK-4298-2021; AAA-3643-2019In this study, a comparative assessment of the mechanical properties of chopped carbon fibre (CF) reinforced polypropylene (PP), polyethylene (PE), polyamide 6 (PA6), and polyamide 12 (PA12) composites was performed. A variation in the composites was obtained by changing the fibre volume fraction of the composite elements under the same manufacturing method and conditions. After blending reinforcement and matrix materials using the extrusion method, the composite materials were manufactured in the shape of plates with thermoforming. The composites' tensile and 3-point bending tests were carried out, and the surface morphology of the fractured surfaces was examined by Scanning Electron Microscope (SEM). As the fibre content in all matrices increased, the efficiency of the fibre in the composites decreased. Finally, ANOVA analysis and mathematical model development by the least square optimization method were performed to analyse and fit experimental data. As a result of the ANOVA analysis, it was seen that the matrix type was more effective on the composite than the fibre type. The error of the modelling performed is less than 20% for the tensile and three-point bending tests.Publication Modeling the consumption of sewing thread for stitch class 301 through image analysis by using Fourier series(Sage Publications Ltd, 2021-05-26) Javed, Zafar; Ahmad, Fayyaz; Khan, Qammar; Naeem, M. Salman; Javaid, M. Usman; Jabbar, Abdul; Hassan, Zameerul; Karahan, Mehmet; KARAHAN, MEHMET; Teknik Bilimler Meslek Yüksekokulu; AAK-4298-2021This research work aims at modeling the sewing thread consumption for stitch class 301 through image analysis by using Fourier series. A mathematical model was developed by using the geometry of stitch class 301 for calculating sewing thread consumption. The modeling of stitch class 301 was conducted by changing the stitch density and thickness of the stitched fabric. The stitch density was adjusted by varying the stitch length (2, 3 and 4 mm) and the thickness of stitched fabric (2, 3 and 4 plies of fabric).The interlacement of sewing thread between the needle and bobbin was used for the measurement of arc length of one stitch. The total consumption of sewing thread was determined by multiplying the arc length by 4. The developed model was verified by using nine different stitched samples for comparing the predicted and measured values of sewing thread consumption. This model predicted the sewing thread consumption with 95% accuracy. Error percentages were also calculated for determining the major influencing factors that affected the sewing thread consumption. The proposed model can effectively be employed in garment industries for determining sewing thread consumption.Publication Investigation of impact properties of para-aramid composites made with a thermoplastic-thermoset blend(Sage Publications, 2021-06-01) Khan, Muhammad Imran; Umair, Muhammad; Hussain, Rizwan; Karahan, Mehmet; Nawab, Yasir; KARAHAN, MEHMET; Teknik Bilimler Meslek Yüksekokulu; AAK-4298-2021During impact, thermoset composites show brittle behaviour, whereas thermoplastic composites show a relatively ductile behaviour with higher absorption of impact energy. The research on the investigation of the impact performance of composites with thermoplastic resin and/or with a blend of thermoplastic and thermoset resins found rare. In the present study, both thermoset (phenolic, vinyl ester) and thermoplastic (Polyvinyl butyral - PVB) matrices were used with Para-aramid reinforcement for the development of five-layered composite samples. Drop weight impact, Charpy impact, flexural (three-point), and hardness tests were conducted to assess the performance of the composite samples. The developed thermoplastic composites showed superior impact properties as compared to thermoset composites except for out-of-plane deformation (trauma). This deformation was reduced using a blend of PVB and Phenolic. The composite made with blend absorbs 8-9% more energy as compared to Phenolic composites with almost the same value of trauma. Overall, damage area is also lesser in the case of composite made using a blend. The experimental results are validated by one-way ANOVA (Tukey) statistical analysis.Publication Comparative evaluation of mechanical properties of short aramid fiber on thermoplastic polymers(Sciendo, 2023-03-01) Arı, Ali; Arslan, Orhun; Bayram, Ali; BAYRAM, ALİ; Karahan, Mehmet; KARAHAN, MEHMET; Mühendislik Fakültesi; Makine Mühendisliği Bölümü; AAA-3643-2019 ; AAK-4298-2021This study investigated the mechanical performance of short aramid fiber on polypropylene, polyethylene, polyamide 6, and polyamide 12. Extrusion, press molding, and CNC cutting methods were used in the production of composite samples. Tensile, three-point bending, drop weight and hardness tests of the composites were carried out. As the fiber volume fractions increased, the mechanical properties of the composites improved, but the most efficient fiber fractions for each matrix changed. To analyze the performance of the fibers in the matrix on the composites, scanning electron microscope (SEM) images of the fractured surfaces as a result of tensile and drop weight tests were examined. As the fiber volume fractions increased, the fiber deformation increased, and as a result, the mechanical performance of the composites was adversely affected. Analysis of variance (ANOVA) and F test were performed using signal/noise values to analyze in detail the effect of experimental parameters on output values. Finally, the results of a regression equation model were compared with the experimental readings. It was found to be in good agreement with the model and the results of the experiment.