Yazar "Taskin, Vedat" seçeneğine göre listele
Listeleniyor 1 - 13 / 13
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Bending and free vibration analysis of Levy-type porous functionally graded plate using state space approach(Elsevier Sci Ltd, 2019) Demirhan, Pinar Aydan; Taskin, VedatThis paper aims to investigate the free vibration and bending characteristics of porous functionally graded (FG) plate with two opposite simply supported edges based on a four variable plate theory. Material properties of porous FG plate are defined by rule of the mixture with an additional term of porosity in the through-thickness direction. Equations of motion are derived using Hamilton principle. State-space approach is used to obtain the governing equation of porous FG plate. The effect of porosity parameter, slenderness ratio, and the power-law index is investigated on bending and vibration of porous FG plate. The results are compared with available results in the literature to verify this theory.Öğe The Effects of Different Reinforcement Ratios on Wear Behaviors in EN AW 5754 (AlMg3)/SiCp Composite Materials Produced with the Squeeze Casting Method(2022) Taskin, Vedat; Yakut, Rifat; Taşkın, Nilhan Ürkmez; Kılıç, CumaIn this study, SiCp particles were reinforced at volumetric ratios of 5%, 10%, 15% and 20% into the EN AW 5756 (AlMg3) metal matrix composite by using the squeeze casting method. The squeezing process was carried out for 10 seconds under a pressure of 80 MPa. The changes in the wear behaviors and friction coefficients of the EN AW 5754/SiCp composite samples were examined under1.0 N force, 5000 cycles and with a 0.04 m/s sliding speed. As a result of the experiments, it was found that the friction coefficient value increased from the non-reinforced alloy to the 10% SiCp-reinforced composite, while it then decreased in the 15% and 20% SiCp-reinforced composites. Moreover, the amount of wear in the composite material increased as the ratio of the reinforcement increased, and the highest wear occurred in the 10% SiCp-reinforced composite. This wear rate decreased in the 15% reinforced composite and then increased in the 20% reinforced composite. The deformation wear statuses of the composite materials that were used in the experiments were examined by conducting SEM (Scanning Electron Microscopy) and EDS (Energy-Dispersive Spectrometry) analyses. In these examinations, it was observed that the 5% and 10% SiCp reinforcements did not show a homogeneous distribution in the matrix, but the 15% and 20% SiCp reinforcements were homogeneously distributed in the matrix material.Öğe Fiber Metal Laminatların Şekillendirilebilme Kabiliyetinin İncelenmesi(2020) Işıktaş, Ali; Taskin, VedatBu çalışmada, havacılık sektöründe kullanılan fiber metal laminatların (FML)şekillendirilebilme kabiliyeti deneysel olarak incelenmiştir. FML numunelerin altve üst tabakalarında iki farklı kalınlıkta (0,6 ve 1,2 mm) Al5754-H22 sac levhalarkullanılmıştır. FML numunelerin orta tabakasında prepreg karbon elyaf kumaştanüretilen karbon elyaf plaka bulunmaktadır. FML malzemelerin şekillendirilmekabiliyetini incelemek amacıyla numuneler farklı bükme açılarındaşekillendirilmiştir. Deneyler sırasında 0,6 mm Al 5754 kullanılan FML numunelertüm bükme açılarında şekillendirilirken, 1,2 mm Al 5754 kullanılan FMLnumunelerin 75° ve 90° bükme testlerinde ise numunelerin dış tarafındakialüminyum tabakasında yırtılma hasarı görülmüştür. Ayrıca FML numunelerinşekillendirilmesinde, bükme açısı ve alüminyum tabaka kalınlığının artmasıylabükme kuvveti değerinin arttığı tespit edilmiştir.Öğe Free vibration analysis of functionally graded beams with simply supported edges(Elsevier Sci Ltd, 2007) Aydogdu, Metin; Taskin, VedatFree vibration of simply supported FG beam was investigated. Young's modulus of beam varies in the thickness direction according to power law and exponential law. Governing equations were found by applying Hamilton's principle. Navier type solution method was used to obtain frequencies. Different higher order shear deformation theories and classical beam theories were used in the analysis. Free vibration frequencies and some mode shapes were given for different material properties and different slenderness ratios. (c) 2006 Elsevier Ltd. All rights reserved.Öğe Investigation of Thermal Conductivity and Sound Absorption Properties of Rice Straw Fiber/Polylactic Acid Biocomposite Material(Taylor & Francis Inc, 2022) Agirgan, Mehtap; Agirgan, Ahmet Ozgur; Taskin, VedatIn the last decade, there has been an increasing trend in the use of agricultural wastes as reinforcements for high value-added composite materials as an ecological approach. In our previous study, a nonwoven fabric was produced from rice straw fibers. In this study, the previously obtained nonwoven reinforcement material and the polylactic acid (PLA) in granule form are used in the hot press process to produce new single- and double-layered biocomposite materials. The characterization of the obtained composite materials is made using Scanning Electron Microscope (SEM), Fourier-Transform Infra-red Spectroscopy (FTIR), and Differential Scanning Calorimetry (DSC) instrumental methods. The thermal conductivity and sound absorption properties of the materials are also investigated. The double-layer composite material has the highest sound absorption coefficient value, which is almost 0.99 while the single-layer material's is around 0.34. According to the thermal conductivity measurement results, the thermal conductivity of the single-layer composite material is 0.02564 W/m.K and that of the nonwoven material produced with rice straw which is 0.01618 W/m.K. The thermal conductivity of the single-layer composite material is approximately 50% higher than that of the nonwoven material. The single-layer composite material can be preferred in industrial insulation applications since the material with a low thermal conductivity coefficient is the best choice for thermal insulation purposes.Öğe Levy solution for bending analysis of functionally graded sandwich plates based on four variable plate theory(Elsevier Sci Ltd, 2017) Demirhan, Pinar Aydan; Taskin, VedatIn the present study, static analysis of a functionally graded sandwich plate with two opposite simply supported edges is studied using a four variable refined plate theory. The core of sandwich plate is assumed isotropic and material properties of face layers are assumed graded through thickness direction by the power law. Displacement fields are defined by using the four variable plate theory. Equilibrium equations of the sandwich plate are obtained using virtual work principle. Levy type solution with state space concept is used to derive governing equations. The results of deflection, normal and shear stress of uniformly loaded functionally graded square sandwich plates with two opposite simply supported edges are presented. The accuracy of the solution is verified by comparing it with available results in the literature. (C) 2017 Elsevier Ltd. All rights reserved.Öğe The Morphologies and Wetting Properties of CK40 and AA2024 Surfaces Produced by Chemical Etching and Stearic Acid Modification(Maik Nauka/Interperiodica/Springer, 2023) Taskin, Nilhan Urkmez; Beji, Cigdem Ovaci; Ordu, Fatih; Taskin, VedatBy applying surface modification after chemical etching, superhydrophobic aluminum and steel surfaces were obtained. With different etching times, from all surfaces, different surface roughness values (Ra) were obtained. The effect of Ra's on surface contact angles (CA) was determined by applying surface modification with stearic acid (STA) to all surfaces under the same conditions. With increased etching time, the surface roughness of both aluminum and steel has increased. Thus, in the current study, wettability seems to be affected only by the changes in surface roughness values. Although the etching reactive and the modification procedure are being same, higher contact angles were obtained on steel surfaces in shorter etching durations compared to aluminum surfaces. The maximum contact angles measured were 125.35 +/- 8.32 degrees on aluminum surfaces and 164.68 +/- 3.62 degrees on steel surfaces. With the current etching method, the minimum etching times required to reach the hydrophobic/superhydrophobic structure for the CK40 and the AA2024 samples were determined. Furthermore, optimum etching times under 10 min for CK40 and under 30 min for AA2024 were determined achieve the maximum contact angle.Öğe Nonwoven Production from Waste Rice Straw by Using Enzymatic Method(Taylor & Francis Inc, 2020) Agirgan, Mehtap; Taskin, VedatIn this study, the nonwoven fabric is produced by rice straws to utilize agricultural organic waste. Rice straws dried after harvest are pretreated with NaOH, pectinase enzyme and wetting agent. Washed and softened fibers are cut at 4-5 cm staple length, blended in carding engine with cotton at 9/1 ratio. By carding band and needle punch process nonwoven fabric is obtained. SEM, EDX and FTIR analyses are applied on the fabric. Product's inspection verified that pretreatments provided smoothness, removed noncellulosic substances, and decreased hydrophobic structure. Thus, a new nonwoven material to be used in textile is produced.Öğe Springback Behavior of Fiber Metal Laminates with Carbon Fiber-Reinforced Core in V-Bending Process(Springer Heidelberg, 2020) Isiktas, Ali; Taskin, VedatFiber metal laminates (FMLs) are a kind of hybrid composite material that consist of metal sheets and fiber-reinforced composite layers. The use of FMLs has been particularly increasing in the production of aircraft bodies. However, the springback behavior that occurs during the formation of FML parts has a negative impact on the form of the final product. In the present study, FMLs were manufactured by combining aluminum 5754-H22 sheets and carbon fiber-reinforced plastic sheets by using adhesive. A set of experiments were performed to determine the effect of bending angle, face sheet thickness and core thickness on the springback behavior of FMLs. The results showed that the amount of springback in the FML specimen increased as the bending angle increased. It was found that when the thickness of the face sheet increased, the amount of springback in FML specimens was higher in all bending angles. In addition, the amount of springback in FML specimens decreased as core thickness increased.Öğe Static Analysis of Simply Supported Functionally Graded Sandwich Plates by Using Four Variable Plate Theory(Turkish Chamber Civil Engineers, 2019) Demirhan, Pinar Aydan; Taskin, VedatIn this study, the static analysis of a simply supported square functionally graded sandwich plate is performed. The core of the sandwich plate is assumed to be isotropic and the face sheets functionally graded. The variations in the effective properties of functionally graded face sheets along the thickness are obtained by using Mori-Tanaka Micromechanical Model. Four variable plate theory is used for the displacement fields. The equation of sandwich plate under sinusoidal load is obtained using the virtual displacement principle. Closed form solution is obtained with Navier's approach. Parametric values are obtained for the core and face sheet thickness ratios. The numerical results are compared with the literature and a good agreement between the obtained results and other theories in the literature is observed.Öğe Static analysis of simply supported porous sandwich plates(Techno-Press, 2021) Taskin, Vedat; Demirhan, Pinar AydanIn this study, it is aimed to analyze the bending of porous sandwich plates using the four-variable shear deformation theory. The core of the sandwich plate is assumed to be functionally graded, and face sheets are assumed to be isotropic. The pore distribution of the sandwich plate is considered even and uneven type of porosity distribution. Displacement fields are defined with four variable shear deformation theory. Equilibrium equations of porous sandwich plates are derived from virtual displacement principle. An analytical solution is obtained by Navier's approach. Results are presented for uniformly and sinusoidally distributed loaded porous sandwich plates. Face sheet -core thickness ratio, porosity distribution, amount of porosity is investigated.Öğe Vibration analysis of simply supported functionally graded beams(Springer, 2007) Aydogdu, Metin; Taskin, VedatIn this study, free vibration of simply supported functionally graded (FG) beam was investigated. Young modulus of beam is varying in the thickness direction according to power law and exponential law. Governing equations are found by applying Hamilton's principle. Navier type solution method was used to obtain frequencies. Different higher order shear deformation theories and classical beam theories were used in the analysis. Results were given for different material properties and different slenderness ratios.Öğe Vibration of a variable cross-section beam(Pergamon-Elsevier Science Ltd, 2007) Ece, Mehmet Cem; Aydogdu, Metin; Taskin, VedatVibration of an isotropic beam which has a variable cross-section is investigated. Governing equation is reduced to an ordinary differential equation in spatial coordinate for a family of cross-section geometries with exponentially varying width. Analytical solutions of the vibration of the beam are obtained for three different types of boundary conditions associated with simply supported, clamped and free ends. Natural frequencies and mode shapes are determined for each set of boundary conditions. Results show that the non-uniformity in the cross-section influences the natural frequencies and the mode shapes. Amplitude of vibrations is increased for widening beams while it is decreased for narrowing beams. (C) 2006 Elsevier Ltd. All rights reserved.
