İnşaat Mühendisliği Bölümü Yayın Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/395
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Article Frame Finite Element Model for Nonlinear and Vibration Analysis of Steel Structures With Beam-Column and Column-Base Semi-Rigid Connections(Gazi Univ, Fac Engineering Architecture, 2022) Saritas, Afsin; Ozel, Halil FiratIn this paper, a shear deformable force-based frame finite element with semi-rigid connections is derived for nonlinear analysis of steel structures. Distributed plasticity approach is defined along element length and section depth, and linear or non-linear semi-rigid connection behavior can be specified anywhere along elements without the necessity to define additional nodes and to increase the degrees of freedom of the structural system. To perform vibration analyses with similar accuracy, force-based consistent mass matrix is used considering semi-rigidity in connections and an appropriate shear correction coefficient for I-sections. The element formulation is presented in 2 dimensions to simplify the formulation, and numerical validation and comparison studies are carried out on complex and irregular structures in 2-D and 3-D. In models with semi-rigid connections, the effect of nonlinear behavior on the structural system has been studied in both beam-column and column-bases. In the presented examples, it was possible to push structures higher than the existing displacements, and it was revealed that the nonlinear behavior in the column-base connections could create much more critical results for the structural systems with P-Delta effects. In addition, high-level accuracy results were obtained when performing vibration analyses with the application of force-based consistent mass matrix.Article Citation - WoS: 4Citation - Scopus: 8The Performance of Water Jet Pumps and Their Application in Slurry Transportation(Turkish Soc thermal Sciences Technology, 2023) Kokpinar, Mehmet Ali; Gogus, MustafaThis present work is focused firstly on an experimental investigation for the optimum design of water jet pumps to be used in the hydrotransport of solid particles through pipeline systems. Experiments were conducted in a closed test loop using five types of jet pumps with various dimensions of the driving nozzle, suction nozzle, mixing chamber, and diffuser employing water as driving and suction fluid. The efficiency of each water jet pump element was analyzed and interpretations of results related to each water jet pump were made about the parts to be considered in the optimum design of a water jet pump. From the experimental results, the water jet pump having the optimum mixing chamber, suction nozzle, driving nozzle location, and cross-sectional dimensions produced a maximum efficiency of about 33%. In the second part of the study, the solid particle carrying capacity of water jet pumps in a pipeline system was studied under saltation, moving bed, and heterogeneous flow regimes by introducing seven different types of solid particles having various concentrations into the closed test loop. The effect of jet pumps on separating solid particles from flow in a region was investigated. A curved form of a by-pass system called the 'flow division unit' was added to the main pipeline system and through the flow division unit, then most of the solid particles in the flow were forced to flow towards the suction pipe of the jet pump. As a result of this, only water with very small particle concentrations passed through the centrifugal pumps, and in this way, the wear risk of the centrifugal pump was reduced considerably.Article Effect of Downstream Expansion of a Long-Throated Flume on Flow Properties(Gazi Univ, 2021) Hatipoglu, Murat; Gogus, Mustafa; Ucar, MuhammedLong throated flumes are widely used flow measurement devices that not requiring site-specific level to flow curves and therefore laboratory experiments. In this study, downstream expansion effect of the long throated flumes with rectangular cross section were analysed for the dimensionless parameters derived from Buckingham's pi theorem and some other known hydraulic quantities such as discharge coefficient, approach velocity coefficient, submergence ratio of the flow etc. Therefore, five downstream transitions with different expansion angles were tested. In each test, the critical depth y(c), the flow head at the depth measurement section h(1), minimum required energy dissipater length L-t and the head after hydraulic jump y(2) were measured for both modular and free flow conditions. The relation of hydraulic quantities of calculated dimensionless parameters with relevant parameters; modular limits, approach velocity coefficients and discharge coefficients etc. were graphed to represent the design relationships for long throated flumes.
