Department of Modeling and Design Engineering Systems
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Browsing Department of Modeling and Design Engineering Systems by Subject "civil engineering"
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Item A COMPARATIVE STUDY ON THE WAVE CLIMATE OF SOUTHERN AEGEAN COASTLINE OF TURKEY(2022-02-15) Al-Sammarraie, Khalooq Ahmed Alauldeen; Numanoglu Genç, Aslı; Balas, LaleIn this thesis, the wind and wave climate of southern Aegean Sea coastline of Turkey are studied. Six coastal areas to the South of İzmir Bay are selected for the analysis, namely as Kuşadası, Yalıkavak, Turgutreis, Marmaris, Fethiye and Datça coastal areas. In the wind climate analysis, the over land measurements of General Directoriate of Meteorology (GDM) are compared with the over sea wind estimates of European Centre for Medium-Range Weather Forecasts (ECMWF) operational archive. Additionally, the monthly maximum values of wind speeds are compared with the short-term over sea measurements of GDM. It is concluded that ECMWF over sea wind estimates present the wind conditions better than the over land and over sea wind measurements of GDM. In the wave climate analysis two methods are utilized. First, CEM empirical method is used to estimate the wave heights for the wave climate analysis. ECMWF wind predictions are selected in the CEM method. Secondly, the wave results of WAM numerical model are used for the wave climate analysis directly. In the wave climate the long term and extreme value statistics are studied. The significant wave height results of two methods from the long-term wave statistics are compared by studying nearshore and offshore locations for each coastal area. It is concluded that, for the nearshore part, WAM model gives lower wave heights than the CEM method. For the offshore part, WAM Model gives higher wave heights than the CEM Method, if the fetch lengths are relatively short. For the enclosed basins, it is seen that WAM model under estimates the wave heights, and therefore it is concluded that CEM Method gives more reliable results.Item ELASTIC ANALYSIS OF POLAR ORTHOTROPIC FUNCTIONALLY GRADED ROTATING ANNULAR DISKS(2015-01-30) ESSA, Saad; ARGEŞO, Ahmet HakanSemi-analytical and analytical solutions are presented for polar orthotropic annular functionally graded rotating disks by taking also thickness variation into account. The formulations are performed by referring to polar coordinate system and the material properties are assumed to vary in radial direction. The governing equation of the problems are obtained under the assumptions of plane stress and small deformations. Disks having two types of boundary conditions are considered. The first one is an annular disk having traction free inner and outer surfaces, whereas, the second has a rigid inclusion within and traction free outer surface. Semi-analytical solution is obtained by assuming that elasticity moduli and disk thickness vary according to a nonlinear function in which its shape is controlled by three parameters. Poisson’s ratios are assumed to be constant valued and the variation of density can be described by any form of continuous function. The three parametered nonlinear function is formed by combining the exponential and power forms of variation functions that are widely used in literature for describing material gradation. The analytical solution is determined by considering that the Elasticity moduli, disk thickness and density vary according to power law. Solutions are verified numerically by using a computational method which is based on nonlinear shooting method. Verification examples are given first. Then, parametric analysis that inspects the effects of the degree of orthotropy and material gradation on the elastic responses of rotating disks are presented. In the analysis, elastic limit angular velocities of the disks are evaluated according to Hosford’s criteria.Item EXPERIMENTAL AND ANALYTICAL INVESTIGATION ON IMPACT BEHAVIOR OF CONVENTIONAL AND STEEL FIBER REINFORCED CONCRETE BEAMS(2022-02-22) Najah, Azdeen Saleh; Mertol, Halit Cenan; Tuncay, KağanThis research investigated the experimental and analytical behavior of unreinforced and reinforced concrete beams cast using conventional concrete (CC) and steel fiber reinforced concrete (SFRC) under impact loading. Dramix ZP-305 type steel fibers were used for SFRC. Half of the beam specimens were unreinforced and the others were reinforced using one 8 mm diameter steel reinforcement fixed at center of specimen cross section. Cylinder concrete compressive strengths used in this study were 12 and 26 MPa for CC specimens and 35 MPa for SFRC specimens. Beam specimens had 60×60×500, 100×100×500, and 150×150×500 mm dimensions. The specimens were tested under impact loading using a drop-hammer testing apparatus having a weight of 58.5 N. This weight was dropped from various heights (1.20, 2.00, and 2.95 m for unreinforced specimens and 2.95, 3.00, and 3.04 m for reinforced specimens) based on specimen sizes. The slow motion videos of the tested specimens were recorded using a high-speed camera having a frame rate of 2000 fps. Experimental velocity-time relationships for hammer were obtained by analyzing of recorded impact videos using the TEMA Motion Analysis Software. Beams, hammer, and supports were modeled in ANSYS Finite Element Analysis Program and parameters related to modeling were calibrated based on the test results. Riedel, Hiermaier, and Thoma (RHT) Concrete Model was used in ANSYS Dynamic Explicit AUTODYN solver. The results were compared to the experimental studies on CC and SFRC in this research and input parameters of the model were modified. Comparisons of the experimental and modeling results indicated that velocity-time relationships of hammer showed very good agreement for various concrete compressive strengths and dimensions of specimens. It can be concluded that the calibrated concrete model presented in this study could provide some general guidelines for predicting the behavior of reinforced and unreinforced CC and SFRC under impact loading.Item MODELING SURFACE WATER QUALITY AND NUTRIENT CORRELATION WITH SEDIMENT OXYGEN DEMAND AT DAM WATER RESERVOIR(2022-09-12) ABDULQADER, Noor N.; GÜLER, Enver; NUMANOĞLU, AslıThe work presented here is a model approach based on WASP8 (Water analysis simulation program) a water quality model simulated to represent contaminants at the surface and bottom sediments of the Kurtboğazı dam reservoir in Ankara. Investigated water quality output variables were temperature, nitrate, total phosphorus, total Kjeldahl, dissolved oxygen, Chlorophyll a, and ammonium. To ensure that the model represents the actual case at the reservoir, the results from our simulation model were calibrated using actual data from the Kurtboğazı dam site, and the calibration utilizes statistical techniques. The novelty of this research is the development of a quality model to predict the reactions of state variables that are occurring at the water body and how they interact with each other and their influence on the overall quality status of the Kurtboğazı reservoir, as well as the crucial factors influencing the depletion of oxygen at the water column. The accuracy of the model was checked using statistical techniques in the form of coefficient of determination and relative error which produced excellent ranges of results indicating that our simulated model was able to represent the features at the reservoir site. The Kurtboğazı dam reservoir had been affected by the negative impact arising from dissolved oxygen depletion in the hypolimnetic layer during stratification periods. However, the processes of oxygen consumption at the sediment-water interface are still difficult to grasp conceptually and are mainly linked to sediment oxygen depletion and the phenomena of sediment oxygen demand SOD. The work here presents a simulation model that can be utilized as a helpful tool by any person working in the sector of water management, to estimate and predict the parameters influencing the anoxic condition and benthic flux.