Browsing by Publisher "MIM RESEARCH GROUP"

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    Optimal design of the type III hydrogen storage tank for different carbon/epoxy materials by modified differential evolution method
    (MIM RESEARCH GROUP, 2019) Ayakdaş O.; Aydın L.; Savran M.; Küçükdoğan N.; Öztürk S.
    In this study, the main objective is to minimize the failure index of a cylindrical laminated composite hydrogen storage tank under internal pressure. The first step is to obtain the distribution of stress components based on Classical Laminated Plate Theory (CLPT). The second is to evaluate the burst pressure of the tank according to three different first ply failure criteria and then to compare the results with the experimental and numerical ones from literature. In the final part of the study, the best possible combination of winding angles, stacking sequences and thicknesses of laminates satisfying minimum possible stress concentration will be obtained for different Carbon/Epoxy materials by Differential Evolution Method. The stress components and, the burst pressures reached according to Hashin-Rotem, Maximum Stress, and Tsai-Wu first-ply failure criteria, have been complied with experimental and numerical results in the literature for Type III pressure vessels. Manufacturable Type-III tank designs have been proposed satisfying the 35 MPa burst pressure for different Carbon/Epoxy materials. © 2019 MIM Research Group. All rights reserved.
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    Optimum design of anti-buckling behavior of graphite/epoxy laminated composites by differential evolution and simulated annealing method
    (MIM RESEARCH GROUP, 2019) Akçair M.; Savran M.; Aydın L.; Ayakdaş O.; Öztürk S.; Küçükdoğan N.
    Stacking sequence design and optimization of 64 layered symmetric-balance graphite/epoxy laminated composite have been performed. The optimization problems aim to find the optimum stacking sequence maximizing the critical buckling load by single objective optimization approach. Differential Evolution (DE) and Simulated Annealing (SA) optimization algorithms are proposed to solve the problems. The effect of the aspect ratios (a/b) and in-plane biaxial compressive loading ratios (Nx/Ny) on critical buckling load are investigated. In order to see the effect of discrete increments of fiber orientation angle on critical buckling load, 1°, 5°, 15°, 30° and 45° fiber angle increments are also considered. The results show that (i) the proposed algorithms DE and SA exhibit comparable performance in terms of critical buckling load when compared Genetic algorithm (GA) and Generalized pattern search algorithm (GPSA), (ii) DE and SA find distinct stacking sequence configurations in terms of buckling load for the same laminated structure design problems. © 2019 MIM Research Group. All rights reserved.
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    Tribological properties of PPS/PA46 polymer blends
    (MIM RESEARCH GROUP, 2020) Yıldırım F.; Aydın M.; Yetgin H.
    In this study, the tribological performance of originally 40 wt.% fiber glass reinforced polyphenylene sulfide (PPS-G), polyamide 46 (PA46) and their blends were studied at dry sliding conditions. The materials were mixed and extruded on the twin screw extruder. The blends were dried and tribological test specimens were manufactured by using the injection machine. Wear tests were performed with the configuration of a polymer pin on a rotating X40CrMoV5-1 steel disc. Test conditions were atmospheric conditions having 60, 90, 120 N loads and 0.5, 1.0, 1.5 m/s sliding speeds. The obtained results proved that the coefficient of friction for PPS-G, PA46 and their blends is decrease while the applied load and sliding speed values are increase. On the other hand, the specific wear rate is in increase while the applied load and sliding speed values are in increase. © 2020 MIM Research Group. All rights reserved.
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    Effects of ultra-high frequency induction system on the carbon fiber reinforced thermoplastic composites
    (MIM RESEARCH GROUP, 2020) Çavdar U.; Olgun O.H.
    Because of their exceptional features, advanced composites with polymer matrix attract increasing interest in engineering applications recently. Compared to their weight ratio due to the high endurance and hardness values applications of polymer matrixed composites of lightweight, low density, and high performance are popular in military and civil aerospace, automotive, wind power and many other industries. Nowadays, induction heating of the carbon fiber reinforced thermoplastic composites is one of the most important worldwide studies. Due to the importance of accelerating the rate of production from approximately 180-240 minutes to a few minutes, in this study, the weldability of the carbon fiber reinforced thermoplastic composites was investigated. © 2019 MIM Research Group. All rights reserved.