TR-Dizin İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/396
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Article Numerical Investigation of Sloshing with Baffles Having Different Elasticities(2020) Demir, Abdullah; Dinçer, Ali ErsinLiquid tanks are indispensable members of civil engineering structures like liquidpetroleum gas storage tanks and aerospace structures. Fluids can act unpredictablyunder earthquake excitation or dynamic loads. Loads applied to tank changes duringmotion and there can be deformations at the tank or even at the structure where thetank is placed. This is called sloshing and many researchers study the behavior of it.In this research, behavior of baffles having different elastic modulus is investigatedby a fluid-structure interaction (FSI) method. The numerical method is a fully coupled FSI method proposed by the authors, recently. The method, which is verified bymany problems, uses smoothed particle hydrodynamics (SPH) for fluid domain, finiteelement method (FEM) for structural domain and contact mechanics for coupling ofthese two domains. In analysis, a tank and a baffle having constant initial geometryare excited by harmonic motions. Elasticity of baffle is changed to investigate the effect on sloshing. Results show that tip displacement of baffle has linear relation withits elasticity for higher rigidities. In contrast, tip displacement of baffle has constanttip displacement for lower rigidities.Article Comparative Life Cycle Assessment of the Environmental Impacts of Precast Concrete and Brick Walls(2022) Uzal, Nıgmet; Gülçımen, SedatSon yıllarda, yapı malzemelerinin ve bileşenlerinin çevresel etkilerinin değerlendirilmesine artan bir ilgi vardır. Bu çevresel etkiler göz önünde bulundurularak, kullanıcı ihtiyaçlarının karşılanması ve çevresel etkilerin en aza indirilmesi için uygun yapı malzemelerinin ve teknolojisinin seçimi çok önemlidir. Bu çalışmanın amacı, Yaşam Döngüsü Değerlendirmesi (YDD) metodolojisini kullanarak beşikten kapıya yaklaşımıyla prekast beton duvar ve tuğla duvar üretiminin çevresel etkilerini karşılaştırmaktır. Bu çalışmada, ISO 14040 ve 14044 standardlarına göre SimaPro 9.2 yazılımı kullanılarak YDD uygulanmıştır. Yaşam döngüsü etki değerlendirmesi için CML-IA baseline yöntemi ve Ecoinvent veri tabanı kullanılmıştır. Elde edilen sonuçlar, abiyotik tükenme ve deniz suyu ekotoksisitesi hariç tüm etki kategorilerinde tuğla duvarın prekast beton duvardan daha iyi çevresel performansa sahip olduğunu ortaya koymuştur. Prekast beton ve tuğla duvarın m2 başına küresel ısınma potansiyeli sırasıyla 2.35E+02 kg CO2 eq. ve 2.10E+02 kg CO2 eq. olarak hesaplanmıştır.Article A Methodology for Fast and Accurate Analytical Fragility Analysis of Linear Structural Systems during Wind Storms: ALFA(2023) Ciftci, CihanWind-storms are extremely destructive natural disasters that cause structural damage, and consequently severe personal injuries and casualties. To reduce these injuries and casualties, risk assessment of existing structures and improvement of building design regulations have become important. To assess the risk of structural systems during wind storms, analytical fragility analysis is a recently developed method by providing conditional failure probabilities for the structural systems. However, the analytical fragility analysis requires extensive computational time and effort which makes it infeasible for large scale structures. This proposed paper develops a new methodology (Analytical Linear Fragility Analysis: ALFA) to simplify and to expedite the analytical fragility analysis for linear structural systems without compromising accuracy. ALFA is exemplified by obtaining the fragility curves of 70 different multi-degree of freedom (MDOF) linear mass-column systems subjected to varying wind loading conditions. The fragility curves of the same mass-column systems were also obtained using Monte-Carlo (MC) based brute-force methodology, which is a commonly used computationally expensive method in literature, and results are compared. This comparison yields the conclusion that ALFA is 240 times faster than the brute-force one, without losing accuracy. Moreover, ALFA can be utilized for improvement of performance-based design specifications and for the preliminary risk assessment of nonlinear structural systems.Article Citation - WoS: 1Citation - Scopus: 1The Comparison of Fragility Curves of Moment-Resisting and Braced Frames Used in Steel Structures Under Varying Wind Load(Turkish Chamber Civil Engineers, 2025-03-01) Ozalp, Abdulkadir; Gokdemir, Hande; Ciftci, CihanIn this study, the performance of two different steel structure types (moment-resisting frame and braced frame) under wind loading was compared by addressing the fragility curves of these structure types. To perform this comparison, the dimensions of the members of these structural systems were first determined. Then, nonlinear static pushover analyses were conducted to assess the performance levels of each frame type. After applying these analyses, time-history analyses were performed with 100 different wind loads for each varying equivalent mean wind speed. Afterwards, the probability of exceeding the predetermined structural performance limits of the structure types was determined using Monte Carlo simulation method. Finally, the results of the simulation method were used to adapt the maximum likelihood estimation method to obtain the fragility curves of the structures. To conclude, it has been revealed that the material cost of the structure doubles when diagonal elements are used, but the wind speed required for a 100% collapse probability to occur in the braced frame is twice as high compared to the moment-resisting frame.Article Symbolic Aggregate Approximation-Based Clustering of Monthly Natural Gas Consumption(2024-03-24) Söylemez, İsmet; Ünlü, Ramazan; Nalici, Mehmet ErenNatural gas is an indispensable non-renewable energy source for many countries. It is used in many different areas such as heating and kitchen appliances in homes, and heat treatment and electricity generation in industry. Natural gas is an essential component of the transportation sector, providing a cleaner alternative to traditional fuels in vehicles and fleets. Moreover, natural gas plays a vital role in boosting energy efficiency through the development of combined heat and power systems. These systems produce electricity and useful heat concurrently. As nations move towards more sustainable energy solutions, natural gas has gained prominence as a transitional fuel. This is due to its lower carbon emissions when compared to coal and oil, thus making it an essential component of the global energy framework. In this study, monthly natural gas consumption data of 28 different European countries between 2014 and 2022 are used. Symbolic Aggregate Approximation method is used to analyse the data. Analyses are made with different numbers of segments and numbers of alphabet sizes, and alphabet vectors of each country are created. These letter vectors are used in hierarchical clustering and dendrogram graphs are created. Furthermore, the elbow method is used to determine the appropriate number of clusters. Clusters of countries are created according to the determined number of clusters. In addition, it is interpreted according to the consumption trends of the countries in the determined clusters.Article Redevelopment of Squatting Housing in Turkey in the Case of Altındağ, Ankara(2021-12-29) Akyüz, SinanThe focus of this paper is the redevelopment of the squatter settlements in Ankara Turkey. Most of the articles focus on gentrification and changing neighbourhood social structures but the redevelopment of the squatter settlements also aims the production of formal low-income housing as well as the integration of previous non-formal housing into formal urban space. Therefore, this article suggests that the contemporary redevelopment project of squatters in Ankara, Turkey is a part of a broader strategy of integrating low-income into the formal housing system by cooperating with a part of low-income groups. The research was made in Altındağ, Ankara by using a deep semi-structured interview, and document analyses method. The researcher conducted 25 interviews with residents and 2 interviews with officials.Article Optimal Location Determination of Electric Vehicle Charging Stations: A Case Study on Turkey's Most Preferred Highway(2022-06-30) Gülbahar, İbrahim Tümay; Sütçü, MuhammedToday, electric vehicles are seen as one of the most suitable and environmentally friendly alternatives to internal combustion engine vehicles. An important issue related to the dissemination of electric vehicles is the location of the vehicle charging network and specifically the optimum location selection of the charging stations. Generally, most of the studies focus on popular destinations such as city centers, shopping areas, bus stations, and airports. Although these places are often used in normal life, they can usually provide an adequate solution for daily charging needs due to the number of alternative charging stations. However, finding adequate charging stations is not possible in intercity travels especially in highways. In this paper, we proposed a decision model to determine the location of electric car charging stations in highways. We create an optimization model to decide the optimum locations for the charging stations that can meet the customer demands on the Istanbul-Ankara highway. The proposed model determines optimum charging stations that enable passengers traveling with their electric vehicles to travel in Istanbul-Ankara highway in the shortest time.Article Methods for Multi-Segment Continuous Cable Analysis(2023-06-20) Demir, Abdullah; Polat, UgurCables are invaluable members for some applications of engineering. The specialty is due to its behavior under transverse loads. Having almost no rigidity in transverse direction makes cables different from other structural elements. In most applications, cables are assumed to be two force members. However, not only its weight but also its application with roller supports makes them different structural elements. Generally, cables are assembled as single-segmented cables (SSC) where they are fixed at their ends. However, in most of the SSC applications, cables have intermediate supports which can be rollers or sliders. These type of cable applications are called as multi-segment continuous cables (MSCC). In MSCC systems, the cable fixed at its ends and supported by a number of intermediate rollers. Total length of cable is constant, and the intermediate supports are assumed to be frictionless and stationary. In this prob-lem, the critical issue is to find the distribution of the cable length among the segments in the final equilibrium state, so reactions at all supports can be found. Two methods are proposed for the segment length adjustment based on the stress continuity among the cable. These methods are named as direct stiffness method and tension distribu-tion method (relaxation method). Results calculated from the proposed methods are verified by both the reference benchmark problems and commercial finite element program.Article Citation - WoS: 1Estimating the Power Draw of Grizzly Feeders Used in Crushing-Screening Plants Through Soft Computing Algorithms(Konya Teknik Univ, 2024-01-02) Koken, EkinIn this study, the power draw (P) of several grizzly feeders used in the Turkish Mining Industry (TMI) is investigated by considering the classification and regression tree (CART), random forest (RF) and adaptive neuro-fuzzy inference system (ANFIS) algorithms. For this purpose, a comprehensive field survey is performed to collect quantitative data, including power draw (P) of some grizzly feeders and their working conditions such as feeder width (W), feeder length (L), feeder capacity (Q), and characteristic feed size (F80). 80 ). Before applying the soft computing methodologies, correlation analyses are performed between the input parameters and the output (P). According to these analyses, it is found that W and L are highly associated with P. On the other hand, Q is moderately correlated with P. Consequently, numerous soft computing models were run to estimate the P of the grizzly feeders. Soft computing analysis results demonstrate no superiority between the performances of RF and CART models. The RF analysis results indicate that the W is necessary for evaluating P for grizzly feeders. On the other hand, the ANFIS-based predictive model is found to be the best tool to estimate varying P values, and it satisfies promising results with a correlation of determination value (R2) of 0.97. It is believed that the findings obtained from the present study can guide relevant engineers in selecting the proper motors propelling grizzly feeders.Article Effects of Dry Particle Coating With Nano-and Microparticles on Early Compressive Strength of Portland Cement Pastes(Tulpar Academic Publishing, 2021-12-16) Yorulmaz, Hediye; Özuzun, Sümeyye; Uzal, Burak; İLkentapar, Serhan; Durak, Uğur; Karahan, Okan; Atis, C. D.It is known that nano-and microparticles have been very popular in recent years since their advantages. However, due to the very small size of such materials, they have very high tendency to agglomeration particularly for nanoparticles. Therefore, it is critical that they are properly distributed in the system to which they are added. This paper investigated the effects of dry particle coating with nano-and microparticles to solve the agglomeration problem. For a clear evaluation, paste samples were preferred to detemine the compressive strength. Nano-SiO<inf>2</inf> and nano-CaCO<inf>3</inf>, microCaCO<inf>3</inf> and micro-SiO<inf>2</inf>, also known as silica fume, were selected as particulate additives. It was studied by the addition of various percentages (0.3, 0.7, 1, 2, 3 and 5%) of nano-and microparticles in cementitious systems, replacing cement by weight with and without dry particle coating. Dry particle coating was made by using a highspeed paddle mixer. Portland cement and additive particles were mixed at 1500 rpm for 30 seconds in high-speed powder mixer designed for this purpose. The 3-day compressive strength of the cement-based samples to which particles were added at the specified rates was determined and the effect of the dry particle coating on the early strength was investigated. According to the results, it was observed that the production of paste with the dry particle coating technique gave higher compressive strength compared to the production of paste directly in early period. Especially with dry particle coating, compressive strength increased more than 100% in paste samples containing 0.3% nano-SiO<inf>2</inf> compared to direct addition without coating. © 2024 Elsevier B.V., All rights reserved.