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Öğe DIFFERENT TYPE CONTROLLERS DESIGN FOR STRUCTURES UNDER SEISMIC EXCITATION(INT SCIENTIFIC CONFERENCE SGEM, 2010) Karadag, Hakan Burak; Kalyoncu, Mete; Tinkir, MustafaIn this study, linear quadratic regulator (LQR) and fuzzy logic (FL) controller are designed for displacement control of elastic structure under seismic excitation. MATLAB (R)/SIMULINK toolbox is used for the mathematical modelling of the system and controllers design. Controllers are applied to the structure, components of which are assumed that they have standard stiffness and damping coefficient, to suppress seismical vibration. A hydraulic actuator is used as the control device. Dynamic of the actuators to create the control force to be applied to the structure, involved in the equation of motion of the controlled structure. The equation of motion of the system obtained in state-space model in continuous time is converted to discrete time. The equation of motion of a real building model structure is solved and simulated by using the data of a known earthquake having occurred ago. Numerical simulations and vibration results of the LQR and FL controlled and uncontrolled structure are presented in the form of graphics.Öğe DIRECT RECYCLING OF BRONZE/STEEL CHIPS AND INVESTIGATION ITS MECHANICAL PROPERTIES(INT SCIENTIFIC CONFERENCE SGEM, 2009) Karadag, Hakan Burak; Akdemir, AhmetRecycling of metals has been becoming an attractive subject, lately due to the fact that the depleted resources, high energy consumption and harmful gases emission. Metal machining chips are recycled conventionaly which consist of melting casting. In the paper the method of direct conversion of bronze and steel chips, into finished product without melting, as an alternative way to conventional method is described. Metal chips were comminuted by mechanical milling and for the next processing the granulated chips larger than 2 mm in length were eliminated. Bronz and steel chips were blended at previously designated percentage ratio according to their weight. In recent process, metal chips that pressed at room temperature were sintered. Finally the mechanical properties of the produced composite material were determined and compared with metallurgically produced bronze.Öğe Mechanical properties and microstructure of composites produced by recycling metal chips(SPRINGER, 2018) Aslan, Abdullah; Gunes, Aydin; Salur, Emin; Sahin, Omer Sinan; Karadag, Hakan Burak; Akdemir, AhmetIn this study, the processing and mechanical properties of porous metal matrix composites (MMCs) composed of spheroidal cast iron chips (GGG40) and bronze chips (CuSn10) and formed by hot isostatic pressing were investigated. Bronze chips (CuSn10) were used as a matrix component, and spheroidal cast iron (GGG40) chips were used as a reinforcement component. The MMCs were produced with different CuSn10 contents (90wt%, 80wt%, 70wt%, and 60wt%). The hot isostatic pressing process was performed under three different pressures and temperatures. The produced MMCs were characterized using density tests, Brinell hardness tests, and compression tests. In addition, the consolidation mechanism was investigated by X-ray diffraction (XRD) analysis and scanning electron microscopy. The test results were compared with those for bulk CuSn10 and bulk GGG40. Mechanical tests results revealed that the metallic chips can be recycled by using hot pressing and that the mechanical properties of the produced MMCs were similar to those of bulk CuSn10. XRD and microscopy studies showed that no intermetallic compounds formed between the metallic chips. The results showed that the CuSn10 and GGG40 chips were consolidated by mechanical interlocking.Öğe Production and mechanical characterization of prismatic shape machine element by recycling of bronze and cast-iron chips(GAZI UNIV, FAC ENGINEERING ARCHITECTURE, 2018) Aslan, Abdullah; Salur, Emin; Gunes, Aydin; Sahin, Omer Sinan; Karadag, Hakan Burak; Akdemir, AhmetIn this study, the production and mechanical properties of porous metal matrix composites (MMC's) by recycling of spheroid cast iron chips (GGG-40) and bronze chips (CuSn10) by hot isostatic pressing was investigated. The metal matrix composites were produced with four different CuSn10 contents, three different pressures and temperatures and effects of production parameters on porosity, hardness, flexure properties were examined. Samples were produced in prismatic shape with specified porosity. The mechanical properties were determined by Brinell and Micro Vickers hardness tests and three-point bending test. The consolidation mechanism of metallic chips was also investigated with optic microscopy. It was examined whether any second phase occurred between metallic chips by the help of XRD test. As a result of porosity test, it is found that metal matrix composites can have porosity value of as much as 20%. It is also showed that owing to excessive plastic deformation of Cu Sn10, the hardness of MMC material can be higher than bulk CuSn10. Three-point bending test showed that the flexure properties of MMC materials are is lower than that of bulk CuSn10. As a consequence, it showed that metallic chips were recycled with hot pressing successfully.