Yazar "Arslan, Eray" seçeneğine göre listele
Listeleniyor 1 - 8 / 8
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Analysis on multi-layered and functionally graded spherical pressure vessels(Pamukkale Univ, 2017) Arslan, ErayAnalytical models are presented for both multi-layered and functionally graded thick walled spherical pressure vessels that are subjected to uniform internal or external pressure. A double recursive algorithm is used for the n-layered vessel of which the modulus of elasticity and yield stress are assumed to change stepwise from one layer to another. In the model intended for the continuously graded one, these properties are assumed to vary in radial direction according to a power law. The elastic behaviors under the same loading conditions for such heterogeneous vessels, and the homogeneous ones alike, have been compared. The relationships between the elastic limit load ( according to the yield criterion of von Mises) and the grading indices or number of layers have been investigated. As a result, it has been observed that although the difference between elastic limit load of the functionally graded and that of 2-layered pressure vessels is 70%, this difference decreases to 2% for the 32-layered one. Moreover, yielding may emerge at the inner or outer surfaces of the graded vessel depending on the load and grading parameter however it occurs at (r(n-1))th interface coordinate in the multi-layered one.Öğe Bending of graded curved bars at elastic limits and beyond(Pergamon-Elsevier Science Ltd, 2013) Arslan, Eray; Eraslan, Ahmet N.Analytical and computational models are developed to predict the stress response of functionally graded curved bars under pure bending in elastic and partially plastic states of stress. In the analytical model, the modulus of elasticity and in the computational model, both the modulus of elasticity and the hardening parameter of the bar material are assumed to vary in the radial direction. The analytical model is based on Tresca's yield criterion, its associated flow rule and ideal plastic material behavior, while the computational one is based on von Mises' yield criterion, total deformation theory and a Swift type nonlinear hardening law. The models are verified not only in comparison to the published solutions, but also in comparison to each other. The results indicate that the variation of material properties, especially the variation of modulus of elasticity, strongly affects the deformation behavior of the bar. In a graded bar, yielding may commence at the inner, at the outer or simultaneously at both surfaces despite the fact that yielding initiates at the inner surface in a homogeneous bar. Crown Copyright (c) 2012 Published by Elsevier Ltd. All rights reserved.Öğe Deformation and Electrical Behaviours of Functionally Graded Piezoelectric Curved Sensors(Gazi Univ, 2016) Arslan, ErayA comprehensive analytical model is developed for a functionally graded piezoelectric (FGP) curved bar which is in a closed electrical circuit. Piezoelectric coefficient is assumed to vary in the radial direction according to a power law unlike the corresponding studies in the literature. This assumption constitutes one of the basic novelties of the present investigation. For the verification, the numerical results of the mathematical model for an FGP curved actuator are compared with those of a related study on a linear FGP curved bar in the literature. Next, the model is used to determine the deformation and electrical behaviours of an FGP curved sensor under a couple at its free end section. The presentation of the numerical results for the curved sensors is another novelty of the present study since the numerical results in the related studies in the literature were presented just for the actuators. Results are compared with bimorph piezoelectric curved sensors and the effect of the grading parameter on the mechanical and electrical fields is examined. Numerical results show that FGP curved sensor provides several advantages in terms of the mechanical behavior of the material, and the distribution and production of electric potential in the sensor are affected significantly with the variation of grading parameter.Öğe Generalized plane strain solution of a thick-walled cylindrical panel subjected to radial heating(Springer Wien, 2015) Arslan, Eray; Haskul, MehmetAn analytical model is developed to predict the elastic stress response of a thick-walled cylindrically curved panel subjected to a radial temperature gradient under the assumption of generalized plane strain. The ends of the panel in the angular direction are guided by rigid supports that allow a displacement in the circumferential direction but fix the curvature of the middle surface. As thermal load is applied to the panel, couples act on those ends, giving rise to pure bending conditions even in the case of homogeneous heating. Moreover, the free ends in the axial direction of the panel are taken into consideration. The stresses caused by different types of steady-state thermal loads in the panel are analyzed. Further, the elastic limits leading to plastic flow according to the yield criteria of both Tresca and von Mises are investigated. The results are presented in graphical form.Öğe Radial heating of a thick-walled cylindrically curved FGM-panel(Wiley-V C H Verlag Gmbh, 2017) Haskul, Mehmet; Arslan, Eray; Mack, WernerA cylindrically curved panel in a state of generalized plane strain subject to a radial temperature gradient is discussed by analytical means. The ends of this thick-walled shell are presupposed to be guided in such a way that a displacement in circumferential direction may occur and that the radius of the middle surface remains unchanged. Then, couples act on those ends, giving rise to pure bending condition. The material is power-law functionally graded, and - based on the rule of mixtures - a coherent dependence of all the material properties (except for Poisson's ratio) on the radial coordinate is taken into account. The stresses occurring for both a positive and a negative temperature gradient are analyzed, and one finds that, depending on the grading exponent, the yield limit according to von Mises may be reached either at the inner surface, the outer surface or at both surfaces simultaneously. Numerical results are provided for a steel/aluminum FGM, and it is shown that by appropriate grading not only a reduction of the couples acting at the supports but in some cases also a considerable reduction of the weight of the panel may be achieved. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimÖğe Shrink fit with solid inclusion and functionally graded hub(Elsevier Sci Ltd, 2015) Arslan, Eray; Mack, WernerSince in a shrink fit the transferable moment essentially depends on the interface pressure between inclusion and hub, the interface pressure should be as large as possible. This may be facilitated by a partially plastic design, which however also has some drawbacks like a possible permanent redistribution of the stresses after operating at high angular speeds and temperatures. In contrast to that, in the present study the use of a functionally graded hub in an elastically designed interference fit with solid inclusion is proposed. It is shown that for an appropriate grading not only the weight of the hub can be reduced noticeably as compared to a homogeneous hub, but also that particularly a much better performance at rotation can be achieved, which predominates over marginal disadvantages at high temperatures. The generally valid analytical results provide a comprehensive means for the practicing engineer for the design of this kind of shrink fits. (C) 2014 Elsevier Ltd. All rights reserved.Öğe Tabakalı ve fonksiyonel olarak kademelendirilmiş küresel basınç kapları üzerine analiz(2017) Arslan, ErayÖz: İç ya da dış basınca maruz kalan tabakalı ve fonksiyonel olarak kademelendirilmiş küresel basınç kapları için iki ayrı analitik model sunulmuştur. Her bir tabakasında elastisite modülü ve akma gerilmesinin kademeli bir şekilde değiştiği varsayılan n tabakalı basınç kabı için çift tekrarlamalı (rekursif) bir algoritma kullanılmıştır. Fonksiyonel olarak kademelendirilmiş basınç kabı için ise aynı mekanik özelliklerin radyal doğrultuda bir güç fonksiyonuna bağlı olarak değiştiği kabul edilmiştir. Bu heterojen (ve bunlara ilaveten homojen) basınç kaplarının aynı yük koşulları altındaki elastik davranışları karşılaştırılmıştır. Elastik limit yükü (von Mises akma kretierine göre) ile kademelendirme parametresi (fonksiyonel olarak kademelendirilmiş kap için) ve tabaka sayısı (tabakalı kap için) arasındaki ilişkiler incelenmiştir. Sonuç olarak, iki tabakalı basınç kabında ulaşılan elastik limit yükü ile kademelendirilmiş kabın elastik limit yükü arasındaki farkın %70 civarında olduğu fakat bu farkın 32 tabakalı kapta %2'ye inebildiği gözlenmiştir. Diğer bir yandan, kademelendirilmiş basınç kabında akma, yüke ve kademelendirme parametresine bağlı olarak iç ya da dış yüzeyde oluşabilirken, tabakalı basınç gerçekleşmektedir.Öğe Yielding of two-layer curved bars under pure bending(Wiley-V C H Verlag Gmbh, 2014) Arslan, Eray; Sulu, Ismail Y.Yielding of a curved bar consisting of two layers subject to pure bending is investigated. It is assumed that both layers of the bar are in a state of plane stress and Tresca's yield criterion is used to detect onset of plasticization. Analytical expressions are obtained for the bending moments corresponding to the elastic limit leading to plastic flow. The results show that, depending on material properties and dimensions of the layers, different cases for plastic deformation may occur. Yielding may emerge at the inner or outer surface of the bar or at the interface between two layers. Furthermore, a critical case in which yielding commences at the outer and interface surfaces simultaneously was observed. Numerical results for real engineering materials are presented in graphical form. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
