Person: ŞEFKAT, GÜRSEL
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ŞEFKAT
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GÜRSEL
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Publication Matlab based guis for electromagnet circuit design and analysis(Pamukkale Univ, 2005-01-01) Şefkat, Gürsel; ŞEFKAT, GÜRSEL; Yüksel, İbrahim; Mühendislik Fakültesi; Makine Mühendisliği BölümüNowadays, the usage of computer has become inevitable in the solution of the engineering systems and problems. In this study, the development of easy-to-use and application specific computer programming is considered. The program is based on the GUI of MATLAB technical programming language, which is widely used at the engineering area. As a programming application, a solution of static and dynamic characteristics of different type of electromagnetic circuits is investigated. With the program, user can select the type of magnet and material, and can calculate the size of magnet by entering parameters of the design.Publication Experimental and numerical study of energy and thermal management system for a hydrogen fuel cell-battery hybrid electric vehicle(Elsevier, 2021-08-25) Şefkat, Gürsel; Özel, Mert Ali; ŞEFKAT, GÜRSEL; ÖZEL, MERT ALİ; Mühendislik Fakültesi; Makine Mühendisliği Bölümü; 0000-0002-5686-0195; 0000-0003-2887-3359; AAK-8091-2021; AAP-3077-2021The aims of this study were fourfold: firstly, develop a fuzzy logic control algorithm for enhancing overall energy efficiency of the fuel cell hybrid electric vehicle, secondly, balance the energy consumptions of the battery and fuel cell with aid of gradient descent optimization method, thirdly, use the waste heat of hydrogen vessels by controlling the fuel flow, and finally, operate two energy sources at cold and hot ambient temperatures safely and efficiently. In the current study, a fuzzy logic controller is used to keep of operate the hydrogen fuel cell and battery pack at their optimum temperatures. A detailed mathematical model is established, which includes electric vehicle dynamics, thermal behavior of battery, hydrogen fuel cell and vessel, and the efficiency model of electric motor. Furthermore, numerical simulations related to vessel temperature changes and energy consumption of the hybrid electric vehicle under actual road conditions are validated by experiments. The results demonstrate that total energy consumption including the propulsion system, thermal management system, and fuel supply system is decreased by 9,1% at 18 degrees C thanks to the fuzzy logic control algorithm. Besides, energy efficiency is increased around 7% and 11% at -10 degrees C and 35 degrees C ambient temperatures, respectively, which are extreme scenarios for electric vehicles. Moreover, the developed algorithm provides a successful thermal management strategy regarding waste heat recovery from hydrogen vessels, the temperature of which is controlled by the fuel supply system. (C) 2021 Elsevier Ltd. All rights reserved.Publication Vibrational comfort improvement for a passenger car driver seat(Gmbh, 2023-09-20) Akçay, Serhat; Şefkat, Gürsel; ŞEFKAT, GÜRSEL; Mühendislik Fakültesi; Makine Mühendisliği; 0000-0002-5686-0195; AAK-8091-2021This paper presents an experimental study aimed at providing new insights into passenger vehicle driver seat vibration. The study investigates the effects of various driver seat components on the damping coefficient. By employing a design for six sigma method, an optimized seating solution is proposed to enhance seat comfort levels. The control factors used in this study include seat cushion upholstery, topper foam, cushion foam, pulmaflex, torsion bar and seat structure. Seat position, foam thickness and body mass are considered as potential noise factors. Subjective evaluation of seat comfort is conducted using the SAE J 1441-2016, comparing three different passenger car driver seats. The seats are disassembled from the vehicles and mounted on a six-degree-of-freedom shaker test bench. Vertical vibration data are filtered, and transmissibility curves are experimentally obtained from the seat rail to the seat cushion via a pad. Uncomfortable seat prototypes are then manufactured, and alternative configurations are tested on the shaker. The objective and subjective evaluations of the seat prototypes reveal that lower foam hardness, higher foam density, and flexible upholstery contribute to improved comfort levels. Moreover, the prototype seat with optimum parameters receives a subjective evaluation SAE score of +0.75, indicating an enhancement in comfort.Publication Development of a method for calculating loads on implants and prostheses used for the human skeleton(Bursa Uludağ Üniversitesi, 2023-09-05) Tunc, Ismet Emircan; ŞEFKAT, GÜRSELThe study proposes a novel computational approach for customizing sustainable knee disarticulation prostheses, aimed at improving the quality of life for users. A specialized calculation technique for assessing the loads and moments on the prosthesis was formulated, leveraging MATLAB for solving kinematic equations, Solidworks for motion analysis, and ANSYS Workbench for material and static analysis. The integration of these tools enabled the validation of the design and analytical outcomes. The kinematic solutions accounted for individual and prosthesis weights, analyzing linear and angular dynamics over a motion range pertinent to the prosthetic leg's function. Static analysis was executed to determine maximum force impact on the prosthesis. The study's results were conducive to identifying the most suitable prosthesis characteristics for individuals aged 20 to 80, with a height of 160-190 cm and a weight of 80-120 kg. The prosthetic design promoted ease of movement in activities requiring a range of motion, such as running and jumping. The prosthesis adapted swiftly to body movements, achieving readiness in approximately three seconds. The research underscores the importance of interdisciplinary collaboration between engineers and medical professionals to optimize the anatomical and kinematic aspects of prosthesis design.