İlgi alanları

• MakaleYalnız künye2021/r/gumushane/12092
  Investigation of characterization and tribological behavior of composite oxide coatings doped with h-BN and graphite particles on ZA-27 alloy by micro-arc oxidation

  Kaplan, Erdar; Sukuroglu, Ebru Emine; Cuvalci, Olkan

  This paper investigates the tribological effects of composite oxide coatings grown on ZA-27 surfaces under dry sliding condition. Coating processes were conducted using three different electrolytic solutions through micro-arc oxidation (MAO) method. The base electrolytic solution without any particles as additives was labeled as MAO-Coated, whereas electrolytic solution labeled as Coated-A contained graphite particles and Coated-B contained hexagonal boron nitride (h-BN) particles incorporated into base solution. The morphology of each coated samples were analyzed using a Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD). The friction and wear tests were conducted using a pin-on-disc tester in order to evaluate the tribological behavior. Results indicated the friction coefficients of both Coated-A and Coated-B samples were lower when compared to that of uncoated ZA-27 alloy. Further comparative studies showed Coated-A samples containing graphite particles resulted in the lowest friction coefficient.

  İncele
• BildiriAçık Erişim2018/r/gumushane/15174
  Stress Analysis and Fatigue Behaviour of PTFE-Bronze Layered Journal Bearing under Real-Time Dynamic Loading

  Duman, M.S.; Kaplan, E.; Cuvalci, O.

  The present paper is based on experimental studies and numerical simulations on the surface fatigue failure of the PTFE-bronze layered journal bearings under real-time loading. 'Permaglide Plain Bearings P10' type journal bearings were experimentally tested under different real time dynamic loadings by using real time journal bearing test system in our laboratory. The journal bearing consists of a PTFE-bronze layer approximately 0.32 mm thick on the steel support layer with 2.18 mm thick. Two different approaches have been considered with in experiments: (i) under real- time constant loading with varying bearing widths, (ii) under different real-time loadings at constant bearing widths. Fatigue regions, micro-crack dispersion and stress distributions occurred at the journal bearing were experimentally and theoretically investigated. The relation between fatigue region and pressure distributions were investigated by determining the circumferential pressure distribution under real-time dynamic loadings for the position of every 10° crank angles. In the theoretical part; stress and deformation distributions at the surface of the journal bearing analysed by using finite element methods to determine the relationship between stress and fatigue behaviour. As a result of this study, the maximum oil pressure and fatigue cracks were observed in the most heavily loaded regions of the bearing surface. Experimental results show that PTFE-Bronze layered journal bearings fatigue behaviour is better than the bearings include white metal alloy.

  İncele
• MakaleYalnız künye2015/r/gumushane/19006
  Design of quartz chemical delivery parts for high temperature vacuum chambers base of simulation results

  Kaplan, Erdar; Ünker, Faruk; Çuvalcı, Olkan

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  İncele
• BildiriYalnız künye2013/r/gumushane/15366
  Self-deploying composite shell reflector antenna for Ku-band missions: 1.5 m diameter demonstrator

  Soykasap, Omer; Karakaya, Sukru; Kaplan, Erdar

  Carbon fiber reinforced plastic (CFRP) composite shell reflectors have been developed for space borne antennas due to their light weight, high thermal stability, and high surface accuracy. In order to reduce launch cost and structural mass, compactly folding and self-deployment of the reflector is preferred. In this paper, the full-scale offset reflector with a diameter of 6 m was designed by introducing reinforcements in the central region. After modal analysis was carried out for full-scale reflector model, the suitability of design was determined and 1/4-scaled version was manufactured. The experiments of the demonstrator were conducted for modal analysis, folding, dynamic deployment behavior and surface accuracy. As a result of study, new reflector model was successfully designed with low-mass, manufacturing ease, lower cost and has a monolithic structure, which two opposite edges of the reflector can be rolled toward the center of the reflector for packaging.

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