Browsing by Author "Gucuyen, E"

Now showing 1 - 6 of 6
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    Numerical analysis on corrosion resistance of mild steel structures
    Erdem, RT; Seker, S; Ozturk, AU; Gucuyen, E
    Corrosion resistances of mild steel specimens according to artificial neural network (ANN) analysis were investigated in the scope of this study. Corrosion rate values were taken into numerical analysis as a result of experimental studies under corrosive aggressive media. Mild steel specimens were selected according to the section type varieties such as box, tube and cornier. All steel specimens were subjected to the aggressive media formed using sodium chloride (NaCl with 99.8 % purity) solutions with 3.5, 5.0 and 7.0 % ratios per one liter distilled water and only distilled water. The reduction in corrosion rate has been observed and considered according to some corrosion loss respects. Corrosion rate prediction models were established between corrosion rate and parameters such as mass loss obtained by experimental studies using ANN. ANNs are computing systems that simulate the biological neural systems of the human brain. In this study, ANN analysis was generated to predict the corrosion rate values after experimental studies. Experimental and predicted values were compared by each other and it is seen that a strong relationship was established between them.
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    Impact effect on different sized reinforced concrete specimens
    Erdem, RT; Gucuyen, E; Kantar, E; Bagci, M
    Behavior of structural members under various loads has been a major interest. However, impact loading type is the least known one among them. Researchers have investigated the behavior of structural members under impact effect recently. For this reason, a well-instrumented experimental program is used to understand the impact behavior of six different sized reinforced concrete specimens. All specimens both have longitudinal and transverse reinforcements. A testing apparatus is developed to perform tests under impact loading. Accelerometers, optic photocells, dynamic force sensor, a data logger and connecting cables are used as well as testing apparatus. Free falling height and mass of steel hammer are taken constant in the study. Test program has been successful to provide several data to understand the impact behavior. Drop numbers and rebound movements of the hammer are determined according to damage situations. Acceleration values are measured from four different points of the specimens. The change of velocity and displacement values is determined for all specimens. Impact force is also measured for each free falling movement and absorbed energy values are calculated according to the area under the curve of impact force-displacement graphs. Test results give substantial information about impact resistances of reinforced concrete members.
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    Numerical modelling of floating structure with coupled Eulerian-Lagrangian technique
    Gucuyen, E; Erdem, RT
    Floating structures are complex systems composed of superstructure, floating-mooring components, and anchors. In this study, the behaviours of a pontoon, which is used as a floating structure, and four mooring elements under different wave loading conditions were investigated. A numerical analysis of the coupled motions of the pontoon, mooring lines, and marine environment was performed. While the mooring lines were modelled as wire elements, the pontoon was modelled as a rigid body with six degrees of freedom. Wave loading conditions were represented using two different wave spectra. The first spectrum (Case I) was generated based on a single sinusoidal wave utilising the JONSWAP spectrum, whereas the second one (Case II) was generated based a superimposed multi-sinusoidal wave. Time-varying motions of the pontoon and tensions of the mooring lines were determined based on the numerical analyses for Cases I and II. Critical values were determined using the results of both cases. The numerical solutions were based on bidirectional fluid-structure interaction (FSI) analysis. A fully non-linear free surface simulation was performed using the coupled Eulerian-Lagrangian (CEL) technique. Furthermore, numerical results were compared with the results obtained from analytical solutions of free surface elevations.
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    Early age corrosion of mild steel in aggressive media
    Ozturk, AU; Gucuyen, E; Erdem, RT; Seker, S
    Effects of the time of holding, type of section, and concentration of the solution on the early age corrosion of mild steel are studied. Section types for steel specimens were box, tube, and corner. They were subjected to 3.5%, 5.0%, and 7.0% NaCl solutions. It was established that the concentration of the solution affects the corrosion until reaching the saturation value.
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    Corrosion effects on structural behaviour of jacket type offshore structures
    Gucuyen, E; Erdem, RT
    The application of weight losses to investigate corrosion effects on structural behaviour of an offshore structure under wave loads is presented in this study. Weight losses of sections obtained during previous experimental studies are implemented in the model. The jacket type structural model is analysed in its intact and deteriorated forms to demonstrate corrosion effects. The ABAQUS finite elements program is utilized and the fluid structure interaction (FSI) technique is adopted when modelling the interaction between solid and fluid domains. Mode shapes, first three natural frequencies, displacements of selected points, and maximum stresses, are comparatively presented.
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    Impact behaviour of concrete beams
    Erdem, RT; Gucuyen, E; Kantar, E; Bagci, M
    The determination of behaviour of structural members under load has become increasingly prominent with current advances in technology. The effect of impact on solids should not be ignored. The impact behaviour of non-reinforced concrete beams is investigated in this study both experimentally and using the finite element analysis. Members are tested in laboratory, and the ABAQUS software is used in the analysis. Accelerations, velocities, displacements, impact forces, and energy absorption capacities, have been obtained in the scope of these analyses.