Person: KARAHAN, MEHMET
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KARAHAN
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MEHMET
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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; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; Bursa Uludağ Üniversitesi/Eğitim Fakültesi.; 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.Publication Low velocity impact behaviour of aramid and uhmwpe composites(Inst Chemical Fibres, 2015-05-01) Karahan, Mehmet; Yıldırım, Kenan; KARAHAN, MEHMET; Uludağ Üniversitesi/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 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; Bursa Uludağ Üniversitesi/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 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; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü; Bursa Uludağ Üniversitesi/Meslek Yüksekokulu/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; Bursa Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu.; Bursa Uludağ Üniversitesi/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 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; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü.; Bursa Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu.; 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 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; Bursa Uludağ Üniversitesi/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; Bursa Uludağ Üniversitesi/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 Multi-response optimisation for the development of an activated carbon web as interlining for higher electrical conductivity and emi shielding using grey relational analysis(Inst Chemical Fibres, 2021-01-01) Naeem, M. Salman; Ahmad, Naseer; Javed, Zafar; Jabbar, Abdul; Rehman, Ateeq Ur; Zubair, Muhammad; Gilani, Syed Qummer Zia; Ahmad, Zuhaib; Karahan, Mehmet; KARAHAN, MEHMET; Bursa Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksekokulu.; AAK-4298-2021This paper presents a simple and novel method of producing an activated carbon (AC) non-woven web from acrylic waste derived fin discarded bathmats converted into a nonwoven web by a caidingand needle punching machine. After stabilisation at lower temperature, carbonisation of the stabilised web was performed in a muffle furnace. The carbonisation temperature, the holding time of the activated carbon web at the final temperature, the heating rate to reach the final carbonisation temperature and the number of steps adopted for developing the carbon web were optimised using the grey relational analysis (GRA) approach to get optimum responses of the surface area of the web, electrical conductivity and electromagnetic shielding. The results demonstrated a large improvement in electrical conductivity as surface resistivity decreasedfrom 134.21 Omega.mm to 0.28 Omega.mm, and the corresponding electromagnetic shielding increased to 82.63 dB when the temperature of the carbonisation, the holding time and number of steps were increased. The surface area in the AC web was increased from 73 m(2)g(-1) to 210 m(2)g(-1) with an increase in the carbonisation temperature, the holding time and number of steps to reach thefinal temperature. The optimisation technique used in this work could be successfully used in cost and error reduction while producing an AC web. The optimised AC web was characterised by Brunauer; Emmett and Teller (BET), X-ray diffraction characterisation and elemental analysis (EDX) in order to determine changes in its structure, surface area, degree of crystallinity, inter-layer spacing and proportion of different elements. The AC web developed can be effectively employed as interlining in apparels because of its flexibility and eco-friendly electromagnetic shielding, as it works on the principle of the absorption, reflections and internal reflections of electromagnetic radiations.Publication The effect of manufacturing parameters on various composite plates under ballistic impact(Sage Publications Ltd, 2022-12-01) Arı, Ali; KARAHAN, MEHMET; Kopar, Mehmet; Ahrarı, Mazyar; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Otomotiv Mühendisliği Bölümü.; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği Bölümü.; 0000-0003-3915-5598; AAK-4298-2021; AEL-5372-2022In this study, the usability of several composite plates in level III and level IV body armors were examined, along with the ballistic resistance, protection level, and production parameters of each plate. For level III protection, composite panels are made using the heat pressing method under various pressures, and for level IV composites, ceramic plates of various thicknesses are reinforced on the back with various composite materials. Ballistic tests using the NIJ standards were performed on the created composite panels. There were delaminations between the layers as a result of the ballistic test in the level III protective panels produced at 140 bar pressure, but there was no puncture in the panels produced at 250 bar pressure, and the depth of trauma was reduced to a minimum. These observations were made using samples produced at 90 bar pressure under controlled conditions. Level IV panels were subjected to dry and wet ballistic tests, and the results of these tests showed that K-flex reinforced ceramics were impervious to punctures. It has been found that aramid-reinforced epoxy ceramic panels and UD H62 reinforced ceramics have superior ballistic qualities and are 6% lighter.