https://hdl.handle.net/20.500.12294/2442 Makine Programına ait makaleler bu koleksiyonda listelenir. 2026-06-11T18:46:47Z https://hdl.handle.net/20.500.12294/3881 An investigation on the mechanical behavior of mixed adhesively bonded composite joints subjected to transverse pre-impact following by axial post-tensile Togar, Yunus Emre; Ozenc, Murat In this study, mixed adhesive joints were formed to create a more homogeneous stress distribution in order to increase the failure load that the joints could bear. Single-lap joints (SLJs) made of glass fiber-reinforced plastic (GFRP) composites were formed using a rigid adhesive (Araldite AV138) in the middle and a more flexible adhesive (3 M DP8005) at the ends of the joint. Rigid and flexible adhesives were applied to the surface with lf/lr = 1 and lf/lr = 0.5 bond-length ratio (lf is bond length for the flexible adhesive and lr is bond length for the rigid adhesive). Mono adhesive joints were also created using the same adhesives. Tensile tests at 1 mm/min were carried out without applying pre-impact to some joints and applying 2.5, 3.5, 7.5, and 10 J transverse impacts to other joints to reveal how joint strength changes with the potential impacts to which adhesive joints might be exposed. Mixed adhesive joints bore more load under impact and non-impact conditions compared to mono adhesive joints. The impacts applied in these tests increased the load-bearing capacity of mono DP8005 adhesive joints. The largest decrease of strength after impact was observed for the mixed adhesive joints with lf/lr = 0.5 bond-length ratio. © 2023 Elsevier Ltd 2023-01-01T00:00:00Z https://hdl.handle.net/20.500.12294/2771 An Investigation of Transition Flow in Porous Media by Event Driven Molecular Dynamics Simulation Koç, Muammer; Kandemir, İbrahim; Akkaya, Volkan Ramazan Aim of this study is to investigate the properties of mono-atomic gas flow through the porous medium by using Event-Driven Molecular Dynamics (EDMD) simulation in the transition regime. The molecules and the solid particles forming the porous structure were modelled as hard spheres hence molecule trajectories, collision partners, interaction times and post-collision velocities were calculated deterministically. The porous medium is formed of spherical particles suspended in the middle of the channel and these particles are distributed into the channel in a regular cubic array. Collisions of gas molecules with porous medium were provided by means of the specular reflection boundary condition. A negative pressure boundary condition was applied to the inlet and outlet of the porous media to ensure gas flow. Porosity, solid sphere diameter and Knudsen number (Kn) were initially input to the simulation for different Cases. Thus, the effects of these parameters on mass flow rate, dynamic viscosity, tortuosity and permeability were calculated by EDMD simulation. The results were compared with the literature and were found to be consistent. 2021-01-01T00:00:00Z https://hdl.handle.net/20.500.12294/1798 Effects of Various Helically Angled Grinding Wheels on The Surface Roughness and Roundness in Grinding Cylindrical Surfaces Gavaş, Muammer; Kına, Muammer; Köklü, Uğur Grinding is generally used in the final step of machining metallic materials to achieve the necessary surface quality and dimensions. Grinding wheels with flat surfaces are commonly used in the process of grinding. However, due to the fact that there is a great deal of contact length (corresponding to the grinding-wheel width) between the grinding wheel and the workpiece, effective cooling during the grinding process may not be possible and, consequently, the heat in the deformation region is increased. Due to these reasons, some undesired results such as an unqualified surface and a roundness error take place. Various profiles of the grinding wheel were, therefore, proposed to improve the surface quality and decrease the roundness error by modifying the grinding wheel and developing various methods. In this study, AISI 1050, AISI 4140 and AISI 7131 steel materials were subjected to the cylindrical-grinding process using wheels helically grooved at 15 degrees, 30 degrees and 45 degrees and the obtained results such as the average surface roughness and roundness errors were compared with the results of the flat-surface grinding wheels. The experimental results show that the surface roughness and roundness error are reduced when using a helically grooved grinding wheel and, thus, the quality of the machined parts is improved. WOS: 000366552500003 2015-01-01T00:00:00Z