TR-Dizin İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/396
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Article Thermophysical Properties of Directionally Solidified the Zn-Mg Eutectic Alloy and the Effect of Growth Rates on Electrical Properties(2025-03-25) Bayram, ÜmitThe study aimed to investigate the effect of growth rates (V) on the electrical properties of a Zn–3.0 Mg–2.5 Al (wt.%) eutectic alloy. The alloy was directionally solidified at four different growth rates ranging from 8.28 to 164.12 μm/s. Directional solidification experiments were conducted using a Bridgman-type solidification furnace, which was employed for controlled solidification and minimizing undesirable casting defects, following the alloy's production and casting process. The electrical resistivity (ρ) of the samples, measured using the Four-Point Probe Method (FPPM) available in the laboratory, exhibited an increasing trend ranging from 72.80 to 96.20 (nΩm) with rising growth rates. In other words, the electrical conductivity of the Zn–Mg–Al eutectic alloy varies inversely with the growth rate. Additionally, the thermophysical properties of the eutectic alloy in the casting phase were determined using differential scanning calorimetry (DSC): ΔHf (the fusion enthalpy), ΔCp (the specific heat) and TM (the melting point) (26.69 J/g, 0.043 J/gK, 618.92 K, respectively). The results obtained for the Zn–Mg–Al eutectic alloy reveal that, when compared to Zn-Al-based alloys produced under similar experimental conditions, the elements comprising the alloy and mass proportions lead to microstructural changes, which in turn affect its electrical conductivity.Article Model Updating of a Euler-Bernoulli Beam Using the Response Method(2021-05-31) Oktav, Akın; İnan, Cevher YusufIn this study, the computational model is updated using an analytical model instead of an experimental one. Continuous and discrete parameter models of a Euler–Bernoulli beam are constructed analytically and computationally. To construct the computational models, Ansys™ software is employed, and 1-D beam elements are chosen to get the finite element model of a cantilever beam. To get analytical solutions for the continuous and discrete parameter models, a state-space representation is employed. In the first step, only mass and stiffness matrices are considered to model the beam. Eigenfrequencies and eigenvectors of the beam are calculated. The analytical and computational eigenfrequencies of continuous and discrete parameter models are compared. In the seconds step, non-proportional viscous damping and non-proportional structural damping matrices are introduced into the analytical discrete parameter model. Then, the frequency response functions of the model are generated. The damping matrices are identified using the generated frequency response functions. The damping matrices used in the analytical model, and the damping matrices identified using the frequency response functions are compared. It is observed that the assigned damping matrices and the identified damping matrices are identical, which shows that the computational model can be accurately updated provided the FRFs are available.Article Computational Fluid Dynamics (CFD) Analysis of 3D Printer Nozzle Designs(2024-12-31) Hajili, Rasul; Temirel, MikailAdditive manufacturing, particularly 3D printing, has gained significant attention recently due to its flexibility, precision, and sustainability. Among the various 3D printing technologies, Fused Deposition Modeling (FDM) stands out as one of the most popular due to its affordability, ease of use, and print quality. However, a major drawback of FDM-based 3D printers is their relatively low print resolution. One of the key factors influencing print quality is the nozzle design, especially its geometry. As a result, numerous studies in literature have focused on improving 3D printing performance by optimizing nozzle design. In this study, we investigated the effects of nozzle geometry from a Computational Fluid Dynamics (CFD) perspective, examining three aspects: die angle, outlet size, and outlet shape. The CFD analysis revealed that the die angle primarily influences the shear stress within the nozzle, while the outlet size has a significant impact on velocity and pressure difference. The outlet shape affects shear stress, velocity, and pressure difference to a lesser extent than the die angle and size.Article Ardıl Baraj Yıkılmasının Mansapta Bulunan Elastik Yapı Üzerindeki Etkisinin Yapı-Sıvı Etkileşim Yöntemi ile İncelenmesi(2020-12-15) Dinçer, Ali Ersin; Demir, AbdullahBu çalışmada yazarlar tarafından geliştirilen bir yapı-sıvı etkileşim yöntemi idealize edilmişardıl baraj yıkılması problemi için test edilmiştir. Bu doğrultuda geliştirilen yöntemde, sıvı kısımyumuşatılmış tanecik hidrodinamiği (smoothed particle hydrodynamics - SPH) ile, katı kısım ise sonluelemanlar (finite element – FE) yöntemi ile modellenmiş ve katı ile sıvı arasındaki akupaj, kontakmekanik kullanılarak gerçekleştirilmiştir. Aynı geometrideki ardıl barajlar aralarında mesafebırakmaksızın yerleştirilmiştir. En yüksek konumdaki barajın doluluk oranındaki değişim dikkatealımıştır. Yıkılan barajların mansaptaki elastik bir yapıya etkisi hem yapının deformasyonu yönündenhem de akışkandaki basınç dağılımları yönünden test edilmiştir. Ayrıca serbest akışkan yüzeyi profillerive su hızı profilleri de çalışmada sunulmuştur.