Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Polat, Alper(4)
- Onat, Onur(3)
- Alp, Hevidar(1)
- Ates, Mehmet(1)
- Aydogdu, Burcu(1)
- Bora, Pınar(1)
- Celik, Erkan(1)
- Cemalgil, Selim(1)
- Cimen, Isıl Canan Cicek(1)
- Danabas, Durali(1)
- Etli, Serkan(1)
- Gul, Muhammet(1)
- Ince, Muharrem(1)
- Ince, Olcay K.(1)
- Kaya, Yusuf(1)
- Polat, Berivan Yilmazer(1)
- Polat, Muhammed T.(1)
- Savaş, Sedat(1)
- Tam, Gürkan(1)
- Yön, Burak(1)
- Şükrü Özşahin, Talat(1)
Yayınlar
- MakaleYalnız künye2026Scopus SJRQ3Analytical Solution of Discontinuous Contact Problem in Functionally Graded Layer and Homogeneous Layer
Kaya, Yusuf; Polat, Alper; Şükrü Özşahin, Talat; Bora, Pınar
In the study, the problem of discontinuous contact in two layers, one of which is functionally graded is solved using the theory of elasticity. In this problem functionally graded (FG) layer resting on homogeneous layer and loaded with two different rigid flat blocks. In addition, homogeneous layer is resting on a rigid plane. Frictions on all surfaces are neglected. The heights of the FG layer and the homogeneous layer are h1 and h2, respectively. When solving the problem, displacement and stress equations are substituted in the boundary conditions. Then the problem is demained to singular integral equations. Wherein unknown functions are the contact stresses under the two rigid flat blocks and the slope of the separation. These singular integral equations are solved numerically using the Gauss- Chebyshev integration formulas. The analyzes were performed for different inhomogeneity parameter (βh1), shear modulus ratio (μ2/μ-h1). distance between the rigid blocks ((a3-a2)/h1) and density parameter (γh1). Consequently, the stress distributions and starting and ending points of the separation area between the FG layer and homogeneous layer are determined for several dimensionless quantities.
- MakaleYalnız künye2025Scopus SJRQ2Assessment of seismic fragility of reinforced concrete buildings retrofitted with steel bracing elements: A numerical study
Tam, Gürkan; Yön, Burak
In this study, the effectiveness of reinforcement with steel diagonal elements in a reinforced concrete building was investigated. A typical reinforced concrete building with ground floor+4 floors was designed for the numerical study. All column dimensions were 400×400 mm, all beam dimensions were 250×500 mm, transverse reinforcement spacing in column and beam elements was 100 mm and floor heights were 3 meters. The existing building was strengthened with X steel diagonal elements and two models were obtained. Nonlinear static pushover and incremental dynamic analyses of the buildings were performed. 11 earthquake records were used for incremental dynamic analyses. The acceleration amplitudes of these records were increased from 0.1 g to 1.0 g by 0.1 g and the analyses were performed. In order to model the nonlinear behaviour, lumped plastic hinges were assumed at the ends of the structural elements. As a result of nonlinear static pushover and incremental dynamic analyses of the buildings, capacity curves, maximum responses, inter-storey drifts, hysteretic curves at the ends of selected columns and damage patterns were obtained. Fragility curves were created by considering the damage levels in the buildings. According to the results, the average inter-storey drifts of the building strengthened using X steel diagonal elements decreased by approximately 90% compared to its current condition for 1.0 g PGA, while the damage probability and vibration period were also significantly reduced. In addition, the base shear force encountered by the strengthened building increased more than 4 times compared to its current condition.
AtıfScopus11WoS8
İncele - MakaleYalnız künye2024Scopus SJRQ2Contact analysis in functionally graded layer loaded with circular two punches
Polat, Muhammed T.; Polat, Alper
In this study, contact analysis in a functionally graded (FG) layer loaded with two circular punches is solved using the finite element method (FEM). The problem is consisted of a functionally graded layer that resting on an elastic semi-infinite plane and is loaded with two rigid punches of circular geometry. External loads P and Q are transferred to the layer via two rigid punches. The finite element model of the functionally graded layer is created using the ANSYS package program and a 2-dimensional analysis of the problem is analyzed. The contact lengths, obtained as a result of the analysis are compared with the analytical solution in the literature. In the study, the effects of parameters such as distances between punches, loads, inhomogenity parameter on contact zones, initial separation loads and distances, normal stresses, stresses across depth and contact stresses are investigated. As a result, in this study, it can be said that the magnitude of the stresses occurring in the FG layer is less than the homogeneous layer, therefore the life of FG materials will be longer than the homogeneous layer. When the distance between the punches is 2.25, the initial separation distance is 6.98, and when the distance between the punches is 4, the initial separation distance decreases to 6.10. In addition, when the load increased in the second punch, the initial separation load decreased from 55 to 18. The obtained results are presented in the form of graphs and tables.
AtıfScopus1WoS1İncele - MakaleYalnız künye2024Scopus SJRQ2Some nanotoxicity effects of copper (60-80 nm) and copper oxide (40 nm) nanoparticles on Artemia salina
Cimen, Isıl Canan Cicek; Danabas, Durali; Ates, Mehmet
In this study, nanotoxicity tests were made by exposure of Artemia salina to copper (Cu 60-80 nm) and copper oxide (CuO 40 nm) nanoparticles (NPs) at different concentrations (0.2, 1, 5, 10, 25, and 50 mg/L). The LC50 value of Cu (60-80 nm) NPs on the A. salina individuals at the beginning (0), 24th, 48th and 72nd hours and elimination period was 52.37 mg/L while the LC50 value of CuO (40 nm) NPs was 55.39 mg/L. The results of UV-Vis absorbance values showed that all statistical data revealed that maximum effect was observed between 24-30 hours and 25 ppm absorbance concentration was more effective. The multiple R, correlation coefficient (R2) and adjusted R2 values of Cu NP for the suitable Quadratic model were, respectively; 92.96 %, 86.42 % and 76.71 % while they are 98.31 %, 96.64 % and 94.25 % for CuO NP. Also, the data, was indicated effect size significantly changed based on the type and size of NP. Considering the microscope results, it was clearly noticed that A. salina organisms took the NPs in to their body. The accumulation in the gut of A. salina was observed and the images were taken with phase contrast microscope for both of NPs. The highest decrease for survival rates of A. salina individuals exposed to Cu NP was observed in the 10 ppm concentration (43.47 %) and in the 5 ppm concentration (46.20 %) for CuO NP. The results revealed that Cu and CuO NPS showed different toxic effects and that Cu NPs were more toxic than CuO.
AtıfScopus2WoS2İncele - MakaleYalnız künye2023Scopus SJRQ2Anti-tank impact absorption with a reinforced concrete plate design
Polat, Berivan Yilmazer; Savaş, Sedat; Polat, Alper
Anti-tank weapons are among the infantry weapons used by the armies of many countries. Anti-tank rockets and explosives such as TNT, generally used for armour piercing, are also frequently used in terrorist attacks. These attacks damage the protection facilities built from reinforced concrete. Rockets or similar explosives’ rapid speed and burst temperatures pierce reinforced concrete during strikes, resulting in casualties and damage to crucial strategic structures. This study aimed to devise an economic and applicable reinforced concrete plate that could absorb the impact of anti-tank rockets and Trinitrotoluene (TNT) type explosives. Therefore, 5 different samples, produced from C50 reinforced concrete and 150×150 cm in size, were formed by combining plates of different numbers and thicknesses. Also, a sample, which was a single thick plate, was prepared. In destructive testing, Rocket Propelled Grenade (RPG-7) was used as the anti-tank rocket launcher. As a result of this study, the impact damage was reduced with hollow concrete plate geometries, and recommendations were developed for complete prevention.
AtıfScopus2WoS3İncele - MakaleYalnız künye2021Scopus SJRQ1Experimental design approach for ultra-fast nickel removal by novel bio-nanocomposite material
Ince, Olcay K.; Aydogdu, Burcu; Alp, Hevidar; Ince, Muharrem
In the present study, novel chitosan coated magnetic magnetite (Fe3O4) nanoparticles were successfully biosynthesized from mushroom, Agaricus campestris, extract. The obtained bio-nanocomposite material was used to investigate ultra-fast and highly efficient for removal of Ni2+ ions in a fixed-bed column. Chitosan was treated as polyelectrolyte complex with Fe3O4 nanoparticles and a Fungal Bio-Nanocomposite Material (FBNM) was derived. The FBNM was characterized by using X-Ray Diffractometer (XRD), Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS), Fourier Transform Infrared spectra (FTIR) and Thermogravimetric Analysis (TGA) techniques and under varied experimental conditions. The influence of some important operating conditions including pH, flow rate and initial Ni2+ concentration on the uptake of Ni2+ solution was also optimized using a synthetic water sample. A Central Composite Design (CCD) combined with Response Surface Modeling (RSM) was carried out to maximize Ni2+ removal using FBNM for adsorption process. A regression model was derived using CCD to predict the responses and analysis of variance (ANOVA) and lack of fit test was used to check model adequacy. It was observed that the quadratic model, which was controlled and proposed, was originated from experimental design data. The FBNM maximum adsorption capacity was determined as 59.8 mg g−1. Finally, developed method was applied to soft drinks to determine Ni2+ levels. Reusability of FBNM was tested, and the adsorption and desorption capacities were not affected after eight cycles. The paper suggests that the FBNM is a promising recyclable nanoadsorbent for the removal of Ni2+ from various soft drinks.
AtıfScopus11WoS11OpenAlex7İncele - MakaleYalnız künye2021Scopus SJRQ2Examination of contact problem between functionally graded punch and functionally graded layer resting on elastic plane
Polat, Alper
In this study, continuous contact problem in the functionally graded (FG) layer loaded with a FG flat punch resting on the elastic semi-infinite plane was analyzed by the finite element method (FEM). It was assumed that the shear modulus and density of the layer and punch varied according to exponentially throughout their depth. FG layer's weight was included to the problem and additionally all surfaces were considered as frictionless. Analysis of FG materials was performed with a special macro which was added to the ANSYS program. Firstly, the shear modulus of the punch was considered to be very rigid and the results of initial separation load (λcr) and distance (xcr) were compared with the analytical solution. Afterwards, results obtained from the contact analysis made according to the inhomogeneity parameters (β, γ) between FG punch-FG layer which had been unprecedented in the literature were discussed. As a result, FG punch's stress values at the punch edges where stress accumulations occurred were found to be smaller than the rigid punch. The security of the structure, longer life of the material and ease of production are directly related to the reduction of the stress values. The results obtained in this study are important in this respect. Also this work is the first study that investigates the effect of FG punch on the FG layer.
AtıfScopus8WoS10OpenAlex2İncele - MakaleYalnız künye2021Scopus SJRQ1Effect of pumice powder and artificial lightweight fine aggregate on self-compacting mortar
Etli, Serkan; Cemalgil, Selim; Onat, Onur
An experimental program was conducted to investigate the fresh properties, mechanical properties and durability characteristics of the self-compacting mortars (SCM) produced with pumice powder and Artificial Lightweight Fine Aggregate (aLWFA). aLWFA was produced by using fly ash. A total of 16 different mixtures were designed with a constant water-binder ratio of 0.37, in which natural sands were partially replaced with aLWFA and pumice powder at different volume fractions of 5%, 10% and 15%. The artificial lightweight aggregates used in this study were manufactured through cold bonding pelletisation of 90% of class-F fly ash and 10% of Portland cement in a tilted pan with an ambient temperature and moisture content. Flowability tests were conducted on the fresh mortar mixtures beforehand, to determine the self-compacting characteristics on the basis of EFNARC. To determine the conformity of the fresh mortar characteristics with the standards, mini-slump and mini-V-funnel tests were carried out. Hardened state tests were conducted after 7, 28 and 56 days to determine the flexural strength and axial compressive strength respectively. Durability, sorptivity, permeability and density tests were conducted at the end of 28 days of curing time. The test results showed that the pumice powder replacement improved both the fresh state and the hardened state characteristics of the mortar and the optimum mixture ratio was determined as 15%, considering other studies in the literature. In the aLWFA mixtures used, the mechanical and durability characteristics of the modified compositions were very close to the control mixture. It is concluded in this study that mixtures with pumice powder replacement eliminated the negative effects of the aLWFA in the mortars and made a positive contribution.
AtıfScopus16WoS15OpenAlex17İncele - MakaleYalnız künye2018Scopus SJRQ1Application of Artificial Neural Networks to the prediction of out-of-plane response of infill walls subjected to shake table
Onat, Onur; Gul, Muhammet
The main purpose of this paper is to predict missing absolute out-of-plane displacements and failure limits of infill walls by artificial neural network (ANN) models. For this purpose, two shake table experiments are performed. These experiments are conducted on a 1:1 scale one-bay one-story reinforced concrete frame (RCF) with an infill wall. One of the experimental models is composed of unreinforced brick model (URB) enclosures with an RCF and other is composed of an infill wall with bed joint reinforcement (BJR) enclosures with an RCF. An artificial earthquake load is applied with four acceleration levels to the URB model and with five acceleration levels to the BJR model. After a certain acceleration level, the accelerometers are detached from the wall to prevent damage to them. The removal of these instruments results in missing data. The missing absolute maximum out-of-plane displacements are predicted with ANN models. Failure of the infill wall in the out-of-plane direction is also predicted at the 0.79g acceleration level. An accuracy of 99% is obtained for the available data. In addition, a benchmark analysis with multiple regressionis performed. This study validates that the ANN-based procedure estimates missing experimental data more accurately than multiple regression models.
AtıfScopus33WoS29OpenAlex14İncele - MakaleYalnız künye2017Scopus SJRQ1An integral based fuzzy approach to evaluate waste materials for concrete
Onat, Onur; Celik, Erkan
Waste materials in concrete have been considered as one of the most important issues by the authorities, policy makers and researchers to maintain engineering serviceability in terms of economy, durability and sustainability. Therefore, evaluation and selection of waste materials with respect to multi criteria decision making (MCDM) for the construction industry has been gained importance for recovery and reuse. In this paper, Choquet integral based fuzzy approach is proposed for evaluating the most suitable waste materials with respect to compressive strength, tensile strength, flexural strength, compactness, toughness (resistivity for dynamic loads), water absorption and accessibility. On conclusion, waste tyre and silica fume were determined as the most suitable waste materials for concrete production. The obtained results are recommended to assist the authorities on configuring well designed strategies for construction industry with disposal materials.
AtıfScopus12WoS12OpenAlex9İncele - DergiSmart Structures and Systems
- DergiComputers and Concrete
- DergiAdvances in Nano Research
- DergiStructural Engineering and Mechanics
- DergiAdvances in Concrete Construction