Faculty of Technical Education https://hdl.handle.net/20.500.12619/3930 2026-04-04T21:45:53Z 2026-04-04T21:45:53Z Abdullah Tahir Sensoy Çolak, Murat Irfan Kaymaz Fındık, Fehim https://hdl.handle.net/20.500.12619/34034 2020-01-20T13:07:15Z 2019-01-01T00:00:00Z

Optimal Material Selection for Total Hip Implant: A Finite Element Case Study Abdullah Tahir Sensoy; Çolak, Murat; Irfan Kaymaz; Fındık, Fehim The selection of most proper materials in engineering design is known as an important stage of the design process. In order to successfully complete this stage, it is necessary to have sufficient knowledge about the structure of materials, density, melting point, thermal expansion coefficient, tensile and yield strength, elongation, modulus of elasticity, hardness and many other properties. There are several selection systems that help the design engineer to choose most suitable material that meet the required properties. In the field of bioengineering, the selection of materials and the development of new materials for the clinical needs are increasingly important. In this study, the cases of optimal implant stabilization were investigated, material alternatives for hip prosthesis were evaluated, and optimal materials were determined. Using computerized tomography data with MIMICS software, virtual surgery was applied the hip bone and the implant was attached to bone. Boundary conditions and material properties have been defined, and finite element model has been created. FEA investigation of the mechanical behavior of the hip implant for various material alternatives determined by the CES software showed that the best material candidate is austenitic, annealed and biodurable stainless steel in terms of the micromotions at the implant-bone cement interface regarding osseointegration. This candidate showed 20.69% less strain value than the most commercially used hip implant material, Ti6Al4V. Therefore, the findings of this study suggest that the use of some specific stainless steel materials for implants may reduce the operation cost and increase the operation success for the total hip arthroplasty.

2019-01-01T00:00:00Z C. Teke Çolak, Murat Taş, Mehmet İpek, Mümtaz https://hdl.handle.net/20.500.12619/34033 2020-01-21T07:48:29Z 2019-01-01T00:00:00Z

Modeling of the Impact of Initial Mold Temperature, Al5Ti1B and Al10Sr Additions on the Critical Fraction of Solid in Die Casting of Aluminum Alloys using Fuzzy Expert System C. Teke; Çolak, Murat; Taş, Mehmet; İpek, Mümtaz In the casting of liquid metal, the feeding stops when the mushy zone is clogged and does not allow the transfer of feeding liquid. The growing resistance of the solid dendrites against the fluidity of the feeding liquid is defined as the critical fraction of solid (CFS). CFS value varies depending on many factors such as alloy solidification range, initial mold temperature, and the grain size. Therefore, in many casting simulation applications, it is quite common to get inconsistent results due to insufficient information about the CFS. In this study, a fuzzy expert system (FES) model has been developed in order to determine the value of the CFS in the die casting process, based on the parameters of the alloy type, the initial mold temperature, Al5Ti1B addition and Al10Sr addition. In order to create the rule base for the FES model, 54 die casting experiments have been carried out. The CFS values obtained using the FES model has revealed that the developed model of the FES predicts the CFS value in a high performance.

2019-01-01T00:00:00Z Barlas, Zafer Çolak, Murat https://hdl.handle.net/20.500.12619/3968 2020-01-15T07:30:59Z 2014-01-01T00:00:00Z

Evaluation of the Influence of Upset Stage on Joint Properties of Friction Welded Dissimilar Aluminum-Copper Cast Alloys Barlas, Zafer; Çolak, Murat Friction welding was applied to dissimilar aluminum cast bars alloyed with 2 and 8% copper and the effects of upset time on joint properties were evaluated in this study. The welding process was carried out by a vertical milling machine. Tensile test results show that the ultimate tensile strength increased with an increase in upset time and it reached 88% for Al-2%Cu and 74% for Al-8%Cu base metals. The heat affected zone, thermo-mechanical affected zone, and weld metal were detected in this joint by optical examination, in addition to the base metals. A peak temperature of 436 degrees C was measured in the weld zone. Hardness values also varied according to microstructural changes. The highest hardness values were detected in the weld metal and its average hardness was 217 Brinell.

2014-01-01T00:00:00Z Çolak, Murat Kayıkcı, Ramazan https://hdl.handle.net/20.500.12619/3970 2020-01-15T07:30:59Z 2016-01-01T00:00:00Z

Melt Cleanliness Comparison of Chlorine Fluxing and Ar Degassing of Secondary Al-4Cu Çolak, Murat; Kayıkcı, Ramazan The treatment of liquid aluminum prior to casting typically consists of purging gas and/or fluxes through the melt. By the use of several chemicals during these operations, several environmental problems can occur. Therefore, in this study, the melt cleanliness of Al-4Cu secondary alloy was investigated by comparing the use of argon degassing with or without chlorine fluxing. Reduced pressure test was used to assess the melt quality. Highest quality melt was obtained by Ar degassing with preheated graphite lance without the need to use any chemicals.

2016-01-01T00:00:00Z