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Access Right: info:eu-repo/semantics/openAccessAuthor: Karadogan, Celalettin

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    Conference Object
    Citation - WoS: 20
    Citation - Scopus: 27
    Analysis of Elastic-Plastic Interference-Fit Joints
    (Elsevier Science Bv, 2014) Huyuk, Hava; Music, Omer; Koc, Asuman; Karadogan, Celalettin; Bayram, Cagdas
    This paper presents an examination of the elastic-plastic interference fit joints for simple and complex pin-tube geometries. Mechanics of the process is studied in detail through physical trials and numerical models. Results show there are three distinct stages as the pin is pushed into the tube and that an optimum geometry maximising the joint strength exists. (C) 2014 The Authors. Published by Elsevier Ltd.
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    Article
    Citation - WoS: 7
    Citation - Scopus: 9
    Determination of Coulomb's Friction Coefficient Directly From Cylinder Compression Tests
    (Assoc Mechanical Engineers Technicians Slovenia, 2016) Duran, Deniz; Karadogan, Celalettin
    In this paper, a new method is proposed for the determination of Coulomb's friction coefficient directly from cylinder compression tests. It is based on measuring the immigrated contact area (ICA), which is defined as the lateral surface that comes into contact with the platens after deformation. Preliminary sensitivity analyses showed that ICA is only a function of friction and the strain-hardening exponent at room temperature when a power law relation between the true stress and the true plastic strain is considered. Through intensive numerical simulations by using a code-driven simulation environment, an inverse calculation is done which makes the determination of the friction coefficient possible by using ICA and the strain-hardening exponent of the investigated material. At the end of compression, ICA is usually clearly visible without any precautions; thus, a simplified script is supplied which calculates ICA through digital image analysis made on the end faces of the compressed specimens. This paper includes the complete procedure to determine Coulomb's friction coefficient and a script in which the proposed method is embedded entirely. In addition, practical case studies demonstrated the ease of applicability of the proposed method by employing different materials.
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    Conference Object
    Citation - WoS: 4
    Citation - Scopus: 7
    A Novel and Simple Cruciform Specimen Without Slits on Legs Yet Higher Plastic Strains in Gauge
    (Elsevier Science Bv, 2017) Karadogan, Celalettin; Tamer, M. Emin
    The aim of this study is to obtain higher plastic strains in the central gauge zone of the cruciform specimen under biaxial loading without compromising the simplicity of the specimen geometry and its manufacturing. The proposed novel geometry can be produced easily by a single machining operation performed on a cruciform geometry without requiring slits or any other operation on legs. Geometry of the specimen is determined through finite element analysis. It is observed that there are three characteristic regions with continuous transition in between, in the gauge of the specimen where material deforms under biaxial, plane-strain and uniaxial tensile conditions at the same time. Achieved biaxial strains are recorded to be as high as ever reported in the literature. Success of the geometry is demonstrated through experiments. (C) 2017 The Authors. Published by Elsevier Ltd.