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    Effects of fibre orientations and flow channel patterns on the durability of composite bipolar plates used in PEMFCs
    (Institute of Electrical and Electronics Engineers Inc., 2019) Darıcık, Fatih; Topçu, Alparslan; Tüccar, Gökhan; Aydın, Kadir
    Fuel cells which are electrochemical devices have gained popularity in last three decades as an alternative energy resource. Especially PEM fuel cells (proton exchange membrane or polymer electrolyte membrane) are one of the most developed fuel cell types and use in transportation (automotive) applications. Bipolar plates (BPs), on the other hand, responsible for distribution of reactant gases and collect of current in PEM fuel cell stack. Flow channels mill on bipolar plates for the purpose of distribution of gases to the fuel cell system. These flow channel patterns can be different types such as parallel, serpentine, grid, spiral, cascade. In addition, bipolar plates manufacture from graphite materials usually owing to its superior features such as high electrical conductivity high and corrosion resistance. Besides, they can be manufacture from metallic plates, alloys and composite materials. In present study, carbon/epoxy laminated composite BP models were prepared with four different flow channel patterns (parallel, serpentine, grid and spiral) and four different stacking sequences of reinforced plies. After, the effects of fibre orientations and flow channel patterns on the carbon/epoxy laminated composite BPs were investigated numerically under thermal loads. Deformations of the models and the stresses on the models were evaluated. ANSYS® is used to model the laminated composite models and to perform numerical thermal analysis. Warping of the BPs was determined by benchmarking intact and deformed models and the optimum flow channel pattern. © 2019 IEEE.
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    Öğe
    Production of different metal oxide nanoparticle embedded polymer matrix composite structures by the additive manufacturing technology and investigation of their properties
    (2022) Aktitiz, İsmail; Aydın, Kadir; Darıcık, Fatih; Topçu, Alparslan
    Metal oxide nano additives are widely used as a second phase modifier as they improve the properties of the matrix materials. Nano additives also supply various advantages for polymers which can be employed in additive manufacturing methods. Among the additive manufacturing methods, stereolithography is one of the most remarkable to produce nano-modified polymers because of the easy nano modification of the photocurable resins. In the present study, we mixed the metal oxide particles; Fe2O3, ZnO, NiO, Al2O3, TiO2, and MgO with the photocurable epoxy and used the mixtures to print the specimens. We investigated the structural morphology, thermal and mechanical properties of the printed specimens with an optical microscope, scanning electron microscope, Fourier transform infrared spectroscopy, differential scanning calorimeter, differential thermogravimetric analysis, and microhardness, respectively. Findings proved the dilute agglomeration of the nano additives. Besides, nano additives can improve the thermal stability of the photo-cured polymer. The microhardness of the Fe2O3 added polymers reached 27.63 HV levels while it was measured as 16.16 HV for the pristine samples (similar to 70% raise was experienced). The maximum degradation temperatures of the polymer nanocomposite structures were measured in the range of 396-420 degrees C.