Sürdürülebilir Kalkınma Amaçları

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Araştırmacılar(3)

• Aksağan, Zülfükar
• Çelik, Nida Saatçi
• Doğan, Zülfü Murat

• MakaleYalnız künye2023Scopus SJRQ1/r/munzur/2278
  Laboratory evaluation of oak ash waste for use in hot mix asphalt modification

  Geçkil, Tacettin; Beyza İnce, Ceren; Aksağan, Zülfükar

  In this study, the effect of Oak Ash (OA), a biomass waste, on the mechanical properties of hot mix asphalt (HMA) was investigated and its usability in road engineering was evaluated. For this purpose, firstly, various physical and chemical properties of B70/100 penetration class pure asphalt, OA and crushed limestone aggregate were determined. Then, the optimum asphalt content (OAC) of the mixture was determined according to the Marshall mix design method using aggregate and pure asphalt. Based on this determined content, pure and OA added (1%, 2%, 4% and 6% by weight of asphalt) modified hot mix specimens were prepared. Pure and OA added modified mixture specimens were subjected to Marshall stability, indirect tensile strength (ITS), moisture damage, indirect tensile stiffness modulus (ITSM), static-dynamic creep and calorie tests. According to the results obtained, it has been determined that the OA additive has an improving effect on all mechanical properties of the mixtures, especially on the permanent deformation resistance at high temperatures. It is considered that the use of this additive at a rate of 2% in the hot mixture can increase the resistance of the pavement against deterioration and reduce the maintenance and repair costs of the road.

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  AtıfScopus26·WoS25·OpenAlex24

  İncele
• MakaleYayıncıda açık erişim2023/r/munzur/1856
  Estimation of Contact Lengths Using Deep Neural Network; [Derin Öğrenme Yöntemi ile Temas Uzunlukları Tahmini]

  Polat, Alper

  One of the most common problems in engineering is contact problems. In recent years, researchers have turned to alternative methods that can offer effective solutions in a shorter time, instead of solutions containing complex and long mathematical expressions. This study focuses on the estimation of the contact lengths in a homogeneous elastic layer suppressed by two elastic punches with two solution methods. Firstly, a new model was designed for estimation using Deep Learning Neural Network (DNN), one of the deep learning structures. Estimation of contact lengths was provided with the output of the DNN model, which was fed with the homogeneous elastic layer, the ratio of shear modules of the punches and the input parameters of punch radii. The finite element method was used as the second solution method. The problem was modelled in the ANSYS programme, and the solution was made with the same parameters used in DNN modelled. The results obtained from both solutions were compared with the solutions obtained by the theory of elasticity and classical NN in the literature. It had been seen that the results obtained with DNN and ANSYS were compatible with the results obtained with analytical and classical NN and the margin of error was smaller.

  AtıfScopus5·OpenAlex2

  İncele
• MakaleAçık Erişim2021/r/munzur/6625
  Atık lastiklerden elde edilen siyah karbonun asfaltın işlenebilirlik özelliklerine etkisi

  Geçkil, Tacettin; İnce, Ceren Beyza; Aksağan, Zülfükar

  Bu çalışmada, atık lastiklerden elde edilmiş olan siyah karbon (SK) katkısının asfaltın orta ve yüksek sıcaklıklardaki işlenebilirlik özellikleri üzerindeki etkisi araştırılmıştır. Bu amaçla, penetrasyon sınıfı B 160/220 olan saf asfalta ağırlıkça %5, 10, 15 ve 20 oranlarında SK eklenerek modifiye asfaltlar elde edilmiştir. Saf ve modifiye asfaltların fiziksel özellikleri penetrasyon, yumuşama noktası ve düktilite testleri ile belirlenmiştir. Ayrıca, bağlayıcıların sıcaklık hassasiyetlerinin bir ölçüsü olarak kabul edilen penetrasyon indeksi (PI) değerleri de hesaplanmıştır. Daha sonra, saf ve modifiye bağlayıcıların yüksek sıcaklıklarda bünyelerinde meydana gelen uçucu madde kaybı dönel ince film etüvü deneyi (RTFOT) ile, bağlayıcıların işlenebilirlik özellikleri ise dönel viskozimetre (RV) deneyi ile belirlenmiştir. Fiziksel test sonuçlarına göre, SK katkısıyla bağlayıcıların sertleşme eğiliminin arttığı ve penetrasyon sınıfının B 100/150 olarak değiştiği görülmüştür. Ayrıca, SK katkısıyla bağlayıcıların sıcaklık hassasiyetlerinin azaldığı bu bakimdan en uygun oranın %15SK olduğu görülmüştür. RV sonuçlarına göre, SK katkısıyla bağlayıcıların işlenebilirliklerinin azalarak karıştırma ve sıkıştırma sıcaklıklarının yükseldiği görülmüştür.

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  İncele
• MakaleAçık Erişim2021/r/munzur/6607
  The Effect of Carbon Black on Moisture Performance of Asphalt Pavements

  Geçkil, Tacettin; İnce, Ceren Beyza; Aksağan, Zülfükar

  In this study, the effects of carbon black (CB) additive obtained from waste tires on the moisture performance of hot mix asphalt pavements were investigated. For this purpose, modified asphalts were prepared by adding 5%, 10%, 15% and 20% CB by weight to pure asphalt with penetration class B 160/220. Physical properties of pure and modified asphalts were determined by penetration, softening point and ductility tests, and workability properties were determined by rotational viscometer (RV) test. Then, the optimum asphalt content of the mixture was determined according to Marshall design method by using aggregate and pure asphalt for mixture design. Based on this determined ratio, pure and modified asphalts and hot mix samples were prepared. Pure and CB added modified mixture samples were subjected to Marshall stability, retained Marshall stability (RMS) and indirect tensile strength (ITS) tests. According to the physical test results, it was observed that the hardness and workability temperatures of the modified binders increased with the CB additive. According to the test results of the mixture, it was observed that CB additive had an improving effect on the moisture performance of road pavements due to the significant increases in Marshall stability, RMS and indirect tensile strength ratio (ITSR) values, especially at the rate of 10% CB.

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  AtıfOpenAlex5

  İncele
• MakaleYalnız künye2020Scopus SJRQ2/r/munzur/3745
  Analytical and finite element solutions of continuous contact problem in functionally graded layer

  Kaya, Yusuf; Polat, Alper; Özşahin, Talat Şükrü

  In this study, we solve the continuous contact problem of two layers with different material properties, loaded with two rigid flat blocks and resting on a rigid plane, by analytical and finite element methods. All surfaces are assumed to be frictionless. The upper layer is the functionally graded layer (FG), the height h1, the underlying layer is homogeneous, and the height is h2. It is assumed that the FG layer is isotropic and that the shear modulus and density change exponentially. The FG layer is loaded by means of two rigid flat blocks whose external loads are Q and P (per unit thickness in z direction). In the analytical solution of the problem, stress and displacement expressions are substituted in the boundary conditions and the problem is demoted to singular integral equations where the contact stresses are the unknown functions. These singular integral equations are solved numerically using the Gauss–Chebyshev integration formulas. Two-dimensional finite element analysis of the problem is performed using the ANSYS package program. The analyses are performed for different shear modulus ratios (μ2/μ-h1), distances between the blocks ((c − b)/h1) and inhomogeneity parameters (βh1). The contact stresses under the blocks, the normal stresses (σy) between interfaces of the FG layer and the homogeneous layer and between the homogeneous layer and rigid plane are also measured. In addition, the initial separation load and the initial separation distances (χcr, λcr) of the FG layer and homogeneous layer are determined. The results are presented comparatively as graphs and tables.

  AtıfScopus18·WoS19·OpenAlex14

  İncele
• MakaleYayıncıda açık erişim2020/r/munzur/3346
  Optimal position of piezoelectric actuators for active vibration reduction of beams

  Kouider, Bendine; Polat, Alper

  This paper investigates the optimal placement of piezoelectric actuators for the active vibration attenuation of beams. The governing equation of the beam is achieved by coupled first order shear deformation theory with two node element. The velocity feedback controller is designed and used to calculate the feedback gain and then apply to the beam. In order to search for the optimal placement of the piezoelectric actuators, a new optimization criterion is considered based on the use of genetic algorithm to reduce the displacement output of the beam. The proposed optimization technique has been tested for two boundary conditions configurations; clamped -free and clamped-clamped beam. Numerical examples have been provided to analyze the effectiveness of the proposed technic.

  AtıfScopus22·WoS19·OpenAlex21

  İncele
• MakaleAçık Erişim2019Scopus SJRQ2/r/munzur/3689
  Frictionless Contact Problem for a Functionally Graded Layer Loaded Through Two Rigid Punches Using Finite Element Method

  Polat, A.; Kaya, Y.; Bendine, K.; Özşahin, T.Ş.

  In this study, continuous contact problem in the functionally graded (FG) layer loaded with two rigid flat blocks resting on the elastic semi-infinite plane was analyzed by the finite element method. The two-dimensional numerical model of the FG layer was made with the software added to the ANSYS program. This software can be adapted to all contact problem types by making minor changes. The accuracy check of the program was performed by comparing with the analytical solution of the problem by homogeneous layer and its solution by the finite element method. So, fast and practical solutions can be obtained by the developed finite element method on many applications such as; automotive, aviation and space industry applications. The comparisons made showed that the proposed solution gave good results at acceptable levels. In the problem, it was thought that all surfaces were frictionless. The external loads P and Q were transmitted to the FG layer via two flat rigid blocks. Normal stresses between the FG layer and the elastic plane, initial separation loads, initial separation distances and contact stresses under the blocks were investigated for various dimensionless quantities.

  AtıfScopus14·WoS14·OpenAlex11

  İncele
• MakaleAçık Erişim2018/r/munzur/5221
  Investigation of the contact problem for a partial functionally gradedlayer by using finite element method

  Kaya, Y.; Polat, A.; Bora, P.; Bendine, K.; Özşahin, T.ş.

  The difficulty of producing functionally graded materials (FGM) and the fact that they are more expensive than homogeneous materials emerge as an industrial problem. The starting point of this study is to investigate alternative solution methods that will contribute to the mentioned problem. In parallel, the analysis of the contact problem for a layer, which is loaded by a rigid block and resting on the elastic half plane, is presented in this paper. Only the area under the block is considered as FGM, the other parts are considered homogeneous material, unlike the studies in the literature. There is no analytical solution for this study and it is compared with the solution which is completely functionally graded (FG) layer in the literature by using finite element method (FEM). Material properties of the FG layer are defined by the macro added to the ANSYS program. The analysis for the partial FG layer were compared with the completely FG layer analysis as figures and tables, and as a result it was predicted that partial FGM could be used for the static problems and may also be practical applications in the industry.

  AtıfOpenAlex1·TR Dizin1

  İncele
• MakaleYalnız künye2018Scopus SJRQ1/r/munzur/3818
  Analytical solution to continuous contact problem for a functionally graded layer loaded through two dissimilar rigid punches

  Polat, Alper; Kaya, Yusuf; Özşahin, Talat Şükrü

  A continuous contact problem of functionally graded layer resting on an elastic semi-infinite plane, which is loaded with through two different blocks is addressed in this study. The elasticity theory and integral transformation techniques are used in solution of the problem. The problem is reduced to a system of singular integral equations, and solved numerically by the aid of appropriate Gauss–Chebyshev integration formula. It is assumed that the elastic semi-infinite homogeneous plane is isotropic and all surfaces are frictionless and continuous. The shear modulus and the mass density of the FG layer vary exponentially along the thickness direction.

  AtıfScopus19·WoS18·OpenAlex15

  İncele
• MakaleAçık Erişim2017Scopus SJRQ1/r/munzur/4343
  Evaluation of physical and mechanical characteristics of siderite concrete to be used as heavy-weight concrete

  Esen, Yuksel; Dogan, Zulfu Murat

  The objective of this study is to investigate the usability of siderite aggregates mentioned above as a heavy-weight aggregate in the heavy-weight concrete production and their effects on physical properties of the heavy-weight concrete mixture. For this purpose, normal-weight aggregate content was decreased at the rate of 20%, 40%, 60%, 80% and 100% by volume of the concrete mixture prepared and mixtures were prepared by its substitution with siderite aggregate at the same rates. Based on the increase in siderite aggregate in the concrete mixture, a considerable increase in unit weight, compressive strength and tensile strength of concrete was obtained. Plate-shaped concrete specimens obtained from combined normal-weight and heavy-weight aggregates were exposed to radiation with different X-ray source (118 keV, 164 keV) and Co-60 (1250 keV) beam source at cekmece Nuclear Facility. It is clearly seen that the concrete mixture containing siderite aggregate improved 70% radiation absorption characteristics compared to that of the concrete mixture without siderite aggregate. (C) 2017 Elsevier Ltd. All rights reserved.

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  AtıfWoS53·OpenAlex51

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