Browsing by Author "Gücüyen E."
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Item Capacity determination of steel frame systems according to artifical neural network analysis(CI-Premier Pte Ltd, 2011) Erdem R.T.; Seker S.; Gücüyen E.; Bagci M.Many damages and losses have been occurred after the major scaled earthquakes. Researches have been developed in structural engineering along with other engineering fields with parallel to scientific developments. Determination of collapse safeties of buildings is one of the most efficient ways to observe the behavior of them. Artificial neural networks are computing systems that simulate the biological neural systems of the human brain. Neural Networks types are widely used for engineering problems. Artificial neural network analysis is known as a complex system of the neurons that are connected each other with different influence level. It is composed of a large number of highly interconnected neurons working in unison to solve specific problems. The approach is based on biological models of the human brain's functions. Computation is modeled as a large network of interconnected simple processors and artificial neural network analysis can be trained to recognize input patterns and produce appropriate output responses. The problems that have sufficient training data are suitable for artificial neural network analysis. Prediction of the complex problems and fast evaluation of new examples are the mainly advantages of artificial neural network analysis. In this study, forty steel frame systems which have constant span length and story height are analysed. Earthquake loads are calculated for the frame systems and capacity curves are obtained by using SAP2000 analysis program. The results are evaluated by artificial neural network analysis. The database includes thirty two frames data for training and eight ones for testing the network. Finally the results are compared and given in figures. Suggestions are also proposed.Item Structural behaviour of steel lattice towers under wind loads(CI-Premier Pte Ltd, 2011) Seker S.; Erdem R.T.; Gücüyen E.; Bagci M.Latticed steel towers are used widely in a variety of civil engineering applications. In this paper, structural behavior of 50 and 75 meters lattice towers which are made of L sectioned frame members under 160km/h wind velocity that causes wind force into structure and have 10m2 square antenna area are investigated. The structures (160-10-50, 160-10-75) are handled in two types as space truss composed of pin-jointed (Model A) and rigid main legs surround space truss composed of pin-jointed (Model B). Wind force is based on Gust Factor and calculated according to EIA-TIA 222-F (Structural Standards Abstract for Steel Antenna Towers & Antenna Supporting Structures) code. The aim of this study is obtaining the effective periods, mass sources, inter story drift ratios, maximum displacements of peak points and maximum frame forces of four structures which have different joint connections and height to determine the safety of them.Item Structural behaviour of four legged tubular steel lattice towers under wind loads(CI-Premier Pte Ltd, 2011) Gücüyen E.; Erdem R.T.; Seker S.; Gökkus U.Latticed steel towers are widely used in a variety of civil engineering applications. In this paper, structural behavior of 50 and 75 meters lattice towers which are made of tubular sectioned frame members under 160km/h wind velocity that causes wind force into structure and have 10m2 square antenna area are investigated. The structures (160-10-50, 160-10-75) are handled in two types as space truss composed of pin-jointed (Model A) and rigit main legs surround space truss composed of pin-jointed (Model B). Wind force is based on Gust Factor and calculated according to EIA-TIA 222-F (Structural Standards Abstract for Steel Antenna Towers & Antenna Supporting Structures) code. The aim of this study is obtaining the effective periods, mass sources, interstory drift ratios, maximum displacements of peak points and maximum frame forces of four structures which have different joint connections and height to determine the safety of them.Item Estimation of compression strength of polypropylene fibre reinforced concrete using artificial neural networks(2013) Eredm R.T.; Kantar E.; Gücüyen E.; Anil O.In this study, Artificial Neural Networks (ANN) analysis is used to predict the compression strength of polypropylene fibre mixed concrete. Polypropylene fibre admixture increases the compression strength of concrete to a certain extent according to mix proportion. This proportion and homogenous distribution are important parameters on compression strength. Determination of compression strength of fibre mixed concrete is significant due to the veridicality of capacity calculations. Plenty of experiments shall be completed to state the compression strength of concrete which have different fibre admixture. In each case, it is known that performing the laboratory experiments is costly and time-consuming. Therefore, ANN analysis is used to predict the 7 and 28 days of compression strength values. For this purpose, 156 test specimens are produced that have 26 different types of fibre admixture. While the results of 120 specimens are used for training process, 36 of them are separated for test process in ANN analysis to determine the validity of experimental results. Finally, it is seen that ANN analysis predicts the compression strength of concrete successfully.Item Determination of the impact behavior of concrete and reinforced concrete beams(Association for Scientific Research, 2013) Gücüyen E.; Erdem R.T.; Kantar E.; Baǧci M.Behavior types of structural members under various loads have been a main field of interest in engineering sciences. There have been several studies performed about determining the behavior of members under tensile, compression, bending and torsion loads until today. However, terrorist attacks and destructive earthquakes have aroused interests of scientists and engineers about solutions of impact problems. In this study, behavior of concrete and reinforced concrete beams under impact loads is investigated. For this purpose, a testing apparatus has been created. Data obtained from experimental study are compared with the analysis results of ABAQUS finite elements program.Item Irregular Wave Effects on Dynamic Behavior of Piles(Springer Verlag, 2013) Gücüyen E.; Erdem R.T.; Gökkuş Ü.The paper presents computer-aided numerical analyses which are utilized to investigate the dynamic behavior of piles under wind-generated irregular wave loads. A pile is modeled as a single-degree-of-freedom system. The equation of motion of the system is numerically integrated using a fourth order Runge-Kutta method. The equation of motion includes shape function that is obtained approximately. It is needed to compare the solutions with another method to determine the approximation leads whether significant differences or not. For this purpose the dynamic behavior of structure is modeled by the Time History Tool of SAP 2000 and the results compared with those found by a single-degree-of-freedom system. Irregular wave is represented with equivalent regular waves with two different approaches; based on either superimposed multi-sinusoidal wave (Loading I) or significant wave (Loading II), utilizing the energy spectrum. Wave forces are obtained from Morrison Equation. The analyses account for a soil-pile interaction in a simplified way. As the lateral ground pressure changes by delving deep into the ground, soil spring stiffness also changes. Those forces are calculated separately for different depths and taken into account in both analyses. Lateral displacement of the employed pile varying with the time is obtained from analyses for Loading I and Loading II. Critical results are obtained from which loading is determined. Finally, the frequencies of the external loads and natural frequency of pile are compared to examine whether the resonance came true or not. © 2012 King Fahd University of Petroleum and Minerals.Item Impact effect on different sized reinforced concrete specimens(National Institute of Science Communication and Information Resources (NISCAIR), 2015) Erdem R.T.; Gücüyen E.; Kantar E.; Bağcı 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. © 2015, Indian Journal of Engineering and Materials Sciences. All rights reserved.Item Numerical analysis of deteriorated sub-sea pipelines under environmental loads(Chinese Mechanical Engineering Society, 2015) Gücüyen E.The significant point is the bidirectional interaction technique in FSI analysis while investigating subsea corrosion effect. By this way, pipe environment is accurately modelled and fluid effects are also considered. The effect of external corrosion defects on structural behaviour of a pipeline is studied by creating a nonlinear numerical model based on the finite element method according to ABAQUS analysis program. Corrosion losses of sections are obtained from experimental results and applied to the model. Numerical model is formed by a span of sub-sea pipeline that is subjected to environmental loads. Seismic and wind-generated irregular wave loads are considered as environmental loads. Irregular wave is represented with equivalent eight regular waves via FFT. The pipe is modelled according to two different types which are non-corroded(intact) and corroded (deteriorated) to demonstrate corrosion effects on it. The visible type of corrosion in marine environment is named 'pitting' corrosion, in which the material loss is locally interpenetrated over the surface. By considering this situation, the corroded and non-corroded pipes are modelled as 3D solid elements. The main point is revealing how the subsea corrosion affects the structural behaviour of pipelines on the basis of implementation of experimental results to a model structure due to changes of stresses and displacement. © Chinese Mechanical Engineering Society and Springer-Verlag Berlin Heidelberg 2015.Item Analysis of submarine outfalls subjected to wave load; [Analiza valnog opterecenja podmorskih ispusta](Union of Croatian Civil Engineers and Technicians, 2015) Gücüyen E.Significant improvements haue been made in recent years in the field of submarine outfall construction technology. Such an advancement resulted in structural improvements of submarine outfalls, especially with regard to diffuser pipes, risers, and ports. The paper focuses on the modelling of one part of submarine outfall, namely the diffuser pipes made of various materials, and on the effects of their surroundings (internal and external flows). The fluid structure interaction technique is applied in the analyses. The analyses conducted in the paper show that the highest stress values are obtained in the pipe-riser connections. Highest displacements are observed when wave load is axially applied on the structure.Item Fsi analysis of submarine outfall(Brodarski Institute, 2016) Gücüyen E.; Erdem R.T.; Gökkuş Ü.In the scope of this study, main pipe of the diffuser, risers, ports, internal and external environments forming the discharge system which is used in application are modelled by Finite Elements Analysis (FEA) program to obtain discharge and structural behaviour. The last two spans of the system (20 m) and four ports on these spans are investigated. While the diameter and geometry of the risers and ports remain constant, the diffuser pipe is modelled in three different ways. These are constant sectioned (Model 1), contracting with sharp edge entrance sectioned (Model 2) and gradually contracting sectioned (Model 3) respectively. Among them, only Model 1 is treated as Single Degree of Freedom (SDOF) system and it is simulated by FEA to verify FEA solver in the first place. After structural suitability is confirmed, rest of the models are analysed to determine reaction forces and stresses. The discharge is performed as unsteady external flow as well as steady external flow assumption which is widely used in external flow model in the literature. The discharge analyses are performed in two different ways to verify FEA program. Iterative method is accompanying to FEA program. As a result of this study, proper model for structural and discharge behaviour and external flow effects on discharge velocities are obtained. © 2016, Brodarski Institute. All rights reserved.Item Estimation of compressive strength of cement mortars; [Estimarea rezistenței la compresiune a mortarelor de ciment](Procema SA, 2016) Tuğrul Erdem R.; Uğur Ozturk A.; Gücüyen E.Due to several advantages of cementitious materials especially mortars, they are widely used in construction works. It is important to determine the mechanical properties of cementitious materials to understand their behavior under different effects. In this study, Artificial Neural Networks (ANN) analysis is used to predict the 7 and 28 days compression strength values of cement mortars. Physical-mechanical properties such as flow, setting time and compressive strength of cement mortars incorporating of different chemical admixtures such as air-entraining admixture (HS), naphthalene sulfonate based (SPNS) and modified polymer (SPMP) based admixtures have been determined. The aim of the usage of combinations of air-entraining admixture with two different based superplasticizers is to form different inner structure affecting on compressive strength. All admixtures are used with three different ratios by cement weight and one of them is for overdosage effect. ANN analysis has been performed to predict the compression strength values after 7 and 28 days, in correlation with experimental part of the study. According to this view, 28 sets have been prepared with different combination of admixtures. At early ages, HS015-SPNS2.0 series had the lowest strength whereas the highest compressive strength at 28 days were obtained for HS005-SPMP0.8 series. Obtained compression strength values after 7 and 28 days have also been predicted by ANN analysis. It is stated that the established ANN model indicates a great capacity to predict the compressive strength values in the end. © 2016, Procema SA. All rights reserved.Item Analysis of offshore wind turbine tower under environmental loads(Taylor and Francis Ltd., 2017) Gücüyen E.Researchers have started to use numerical methods in the fluid–structure interactive solutions with the advancing of computing technology. There are few studies investigating bidirectional fluid structure interaction (FSI) analysis due to requirements of high computer capacity. This insufficiency is attempted to be corrected in this study. Offshore wind turbine tower is selected to employ the method under environmental loads. To detect accuracy of the numerical analysis, the tower is modelled as a single-degree-of-freedom (SDOF) system. The equation of motion of the system is numerically integrated by using a fourth-order Runge–Kutta method. Time-varying lateral displacement of the tower and first natural frequency values are obtained from analysis. Afterwards, the structure and the environment are modelled in ABAQUS finite elements program. Bidirectional FSI technique is applied to the structure due to the interaction between ABAQUS/CFD-ABAQUS/Explicit. The accuracy of SDOF and bidirectional FSI analyses results is determined in the end. © 2016 Informa UK Limited, trading as Taylor & Francis Group.Item Experimental study on pipe sections against impact loading(UIKTEN - Association for Information Communication Technology Education and Science, 2018) Gücüyen E.; Erdem R.T.; Kantar E.Pipelines are significant structural systems that transfer necessary materials from one place to another. They are under the effect of static and dynamic loads during their service lives. Investigations have become important to determine the effects of sudden dynamic loads with technological developments. Researchers study the mechanical properties of different materials and structural members under dynamic effects such as earthquake, wind, blast, rock falling and vehicle crushing. For this purpose, different test setups have been developed to investigate the behaviour of test members. In this study, galvanized and water filled galvanized pipe sections having three different diameter values are produced in a laboratory to perform tests under impact loading. The behaviour of the pipes is determined by free falling test apparatus. In addition, measurement devices as accelerometer, dynamic force sensor, lvdt, and data logger are used in the experimental program. So, acceleration, impact force, and displacement values are obtained during the tests. Besides, damage developments of the pipes are also observed to determine the impact resistances of test members. The results are compared to each other and it is stated that while acceleration and impact force values decrease, displacement values increase as the test members approach to collapse damage situation. © 2018 Engin GüCüYEN, R. Tugrul ERDEM, Erkan KANTAR.Item NUMERICAL MODELLING OF SUDDEN CONTRACTION IN PIPE FLOW(Yildiz Technical University, 2019) Gücüyen E.; Erdem R.T.; Gökkuş Ü.In the present work, full-scale numerical simulations of incompressible fluid flow through different locations of sudden contractions are studied according to Computational Fluid Dynamics (CFD) technique. Finite Elements Method is used to numerically solve governing equations via the commercial program ABAQUS including CFD code. Four different locations of contraction zone are utilized to determine the effect of location changes on sudden contraction head loss coefficients (KC). Twelve area ratios (σ) are performed for all zones. Three different Reynolds numbers, remain in laminar flow boundaries, are adopted to determine effects of Reynolds number, as well as location effects. The graphs are constituted by results from computing 48 models for each Reynolds number and the study is concluded with 144 models in the end. In this manner, contraction ratio varying coefficients are obtained for four configurations. According to results, the pressure drop values of the same model for varying contraction locations are different. Maximum values of pressure drops are obtained for the second geometry (G2). Combination of maximum pressure drops and minimum velocity values leads to maximum contraction coefficients for G2. While the area coefficients increase, decreasing values of contraction coefficients of different contraction locations (G) converge in connection with the changing values of velocities and pressure drops. It is necessary to entrain to this remark, for increasing area coefficients. It is stated that KC-σ curves vary due to location change. It is recommended to consider the location varying coefficients while modelling different located contracting flows especially for side contracting flows. © 2019 Yildiz Technical University. All Rights Reserved.Item Experimental and numerical investigation of steel sections under impact effect; [Eksperimentalno i numeričko istraživanje čeličnih profila pri udarnom opterećenju]; [Experimentelle und numerische Untersuchung von Stahlprofilen unter Stoßbelastung](Union of Croatian Civil Engineers and Technicians, 2021) Gücüyen E.; Kantar E.; Erdem R.T.; Alicioglu M.B.Experimental and numerical behaviour of steel test specimens with various types of joints is investigated in this study. A drop weight test setup with necessary test equipment is used for this purpose. The mass and drop height of the hammer is taken to be constant so that the same impact energy can be applied on test specimens. The acceleration, displacement, impact load, drop numbers and drop durations, are obtained through experimental study. In addition, development of damage to test specimens is observed during tests. Numerical analyses of behaviour of test specimens under impact load are also conducted to verify test results using the Abaqus software, and a comparison of results is made. © 2021 Union of Croatian Civil Engineers and Technicians. All rights reserved.Item Analyses of damaged effects on jacket type offshore platform; [Analize učinaka oštećenja na rešetkasto postolje izvanobalne platforme](Croatian Association of Civil Engineers, 2023) Gücüyen E.; Coşkun S.; Tuğrul Erdem R.In this paper, an offshore platform subjected to dynamic loading for different damage cases was modelled via fluid-structure interaction (FSI) analysis. Different damage models were considered in the case where one leg was broken, and the Young’s modulus of the damaged member was reduced with four different severity ratios. In addition to the five damaged structures, the undamaged structure was modelled according to two different leg spacing conditions. Thus, the damaged models were compared among themselves as well as with undamaged models. In this study, models were investigated using a numerical FSI technique. The numerical technique was verified using semi-analytical modelling. At this stage, the equation of motion of one of the structural models was solved using a semi-analytical method based on a multi-degree-of-freedom system. In addition, the numerical environment model was verified using a semi-analytical solution of the free-surface motion equation and the wave velocity-wave force curve. An Abaqus finite-element analysis program was used to model the structures and their surroundings. While the structures were modelled using the Lagrangian technique, the fluid surroundings were modelled using the Eulerian technique. Both the conditions of leg spacing and different severity ratios were modelled, and the most negative damage type was revealed. © 2023, Croatian Association of Civil Engineers. All rights reserved.Item Investigation of concrete slabs made with cement based mortars under impact loads; [Ponašanje betonskih ploča od cementnog morta pri udarnom opterećenju](Croatian Association of Civil Engineers, 2023) Tuğrul Erdem R.; Berberoğlu M.; Gücüyen E.As structural members can be subjected to impact loading during their service life, impact experiments are applied for various materials and objects by taking different methods into consideration. The effect of impact load on concrete slabs prepared with cement-based mortars is investigated in this study. A total of nine slab specimens measuring 500 x 500 x 50 mm are tested within the experimental program. Test specimens are prepared to provide different strength values and tested under impact load using the drop test setup. The impact resistance values of the specimens are determined based on the acceleration, impact load and displacement values, as obtained by measurement devices. In addition, crack distribution of the specimens is observed during impact tests. It has been noted that mortar types have a significant effect on the impact behaviour of the specimens. The finite element analysis is generated for each specimen to verify experimental results. Time histories of the acceleration, displacement and impact load values of the selected test specimens are compared. The relationship between experimental and numerical analysis results is presented, which reveals that the finite element procedure can be used in the evaluation of dynamic response of test specimens under the low velocity impact loading. © 2023 Authors. All rights reserved.Item A Simulation Study on the Performance of Jacket Type Offshore Structures Using Machine Learning Algorithms(Universidad de Cantabria, 2024) Gücüyen E.; Çiftçioğlu A.Ö.; Tuğrul Erdem R.In this study, the behaviors of jacket-type offshore structures are numerically investigated. The examined four-legged models with a total height of 60 m have four layers and three different cylindrical element sizes are fixed to the seabed. The structures are under the effect of environmental forces, including wind and wave loads, as well as operational loads. Three different marine environments have been generated in environmental modeling. Thus, the parametric study has been performed using bidirectional fluid-structure interaction (FSI) analyses of 36 models. Structural outputs such as displacement, reaction force, and stress values are determined by numerical analyses. In the second part of the study, the implementation of machine learning algorithms, including Xgboost, Random Forest, and Support Vector regressors, is employed to automate the assessment of performance in jacket-type offshore structures. The evaluation of these machine learning models in predicting the displacement, reaction force, and stress values of offshore jacket structures is conducted, revealing Xgboost as the most promising technique, although with satisfactory overall performance across all algorithms. These findings provide empirical evidence supporting the feasibility and applicability of employing machine learning methodologies in the analysis of performance for jacket-type offshore structures. © SEECMAR | All rights reserved.Item Numerical analyses of underwater pipe sections under falling objects(Universidad de Cantabria, 2024) Gücüyen E.; Erdem R.T.Underwater and land pipelines are generally modelled under the environmental loads. In addition to these mentioned loads, pipelines are subjected to destructive sudden loads due to accidental drops, ship anchors, rock falls, trawlers fishing and military attacks. In this study, numeric analysis of the same pipe section has been carried out according to the sudden loads caused by falling objects both underwater and on land. Abaqus finite elements analysis software is used in the analysis. While the interaction of pipe-falling object is modelled in the analysis of the pipeline on land, the interaction of pipe-falling object-water is modelled in the underwater pipeline. Bidirectional fluid-structure interaction (FSI) analysis is utilized in the water-pipe-falling object interaction modelling. A fully nonlinear free surface simulation is performed by Coupled Eulerian Lagrangian (CEL) technique in the FSI analysis. Impact parameters such as accelerations, velocities, displacements and impact forces, are determined for both land and underwater pipe sections at the end. Thus, while determining the effect of water on the impact behaviour, the free surface movement of the water in the course of impact is also obtained. © SEECMAR | All rights reserved.Item FLUID STRUCTURE INTERACTION ANALYSES OF ELEVATED STORAGE TANK UNDER SEISMIC LOAD(Academic Publishing House, 2024) Erdem R.T.; Gücüyen E.Elevated storage tanks are used to store fresh and waste water, cereal, oil and petrochemical materials. Therefore they serve in a wide area of utilization in this day and age. Analysis of a half full with water elevated storage tank is performed in the scope of this study. The structure is composed of a steel circular storage tank and frame typed steel stager. The structure is under the effect of earthquake loads as well as operational ones. Numerical model is generated by Finite Elements Analysis (FEA) software including fluid and structure parts. The interaction of the parts is provided by Coupled Eulerian Lagrangian (CEL) technique. While the structure constitutes the Lagrangian part, the fluid constitutes the Eulerian part. Interaction of Eulerian and Lagrangian parts are provided by general contact algorithms. Free surface movement of the water, maximum displacements and natural frequency values with related mode shapes of the structure are obtained after numerical analysis. Numerical results are verified by semi-analytical model, where the structure is modelled as single degree of freedom system. The accordance between results is numerically and visually obtained. The turbulent movement of water under the influence of an earthquake is modelled by utilizing the CEL technique. So, the effect of the dynamic pressure induced by the turbulence on the tank and the structural system has been taken into consideration. © 2024 Academic Publishing House. All rights reserved.