Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 3Citation - Scopus: 5Single- and Multiobjective Optimizations of Dimensionally Stable Composites Using Genetic Algorithms(Springer, 2021) Aydın, Levent; Artem, Hatice Seçil; Artem, Hatice Seçil; Deveci, Hamza Arda; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe present study aims to design stacking sequences of dimensionally stable symmetric balanced laminated carbon/epoxy composites, with different numbers of layers, with a low coefficient of thermal expansion and high elastic moduli. To avoid excessive interlaminar stresses in the composites, the contiguity constraint for plies is also taken into consideration. In the design process, both single- and multiobjective optimization approaches, including genetic algorithms, are utilized. Results showed that stacking sequences ensuring lower thermal expansion coefficients and higher elastic moduli than those of traditional laminate designs can be obtained.Book Part Citation - WoS: 3Citation - Scopus: 4Design and Optimization of Fiber Composites(Elsevier, 2017) Aydın, Levent; Artem, Hatice Seçil; Artem, Hatice Seçil; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn engineering, design, and optimization processes are very important issues to establish sustainable engineering systems. Compared to isotropic materials, it is necessary to deal with more complicated mathematical models that address the material anisotropy for fiber-reinforced composites. Due to the unique characteristics of fiber-reinforced composite materials such as different directional properties, interlaminar stresses, less notch sensitivity, and having positive and negative coefficients of thermal expansion, they require more material constants for characterization of the hygrothermomechanical responses. Therefore, the design process of composites for the effort required or the benefit desired has to be systematic, which includes innovative approaches to synthesize alternative solutions. In this regard, the main goal of all such attempt is relevant to reach minimizing the effort required or to maximize the desired benefit.Book Part Citation - WoS: 4Citation - Scopus: 4Mechanics of Fiber Composites(Elsevier, 2017) Aydın, Levent; Artem, Hatice Seçil; Artem, Hatice Seçil; Öterkuş, Erkan; Gündoğdu, Ömer; Akbulut, Hamit; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe objective of this chapter is to emphasize the context in which the mechanics of fiber composites is examined. Constitutive equations describing the stress-strain relations, micromechanics and acromechanics approaches for mechanical analysis are reviewed. Since interfacial mechanics of composites is of primary importance in discussing the material behavior, this concept is also presented with its constitutive and governing equations. Finally, at the end of the chapter, strength failure theories for orthotropic materials and dynamic behavior of composites are discussed.Article Citation - WoS: 13Citation - Scopus: 17Design of Dimensionally Stable Composites Using Efficient Global Optimization Method(SAGE Publications Inc., 2019) Aydın, Levent; Artem, Hatice Seçil; Aydın, Olgun; Artem, Hatice Seçil; Mert, Ali; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyDimensionally stable material design is an important issue for space structures such as space laser communication systems, telescopes, and satellites. Suitably designed composite materials for this purpose can meet the functional and structural requirements. In this paper, it is aimed to design the dimensionally stable laminated composites by using efficient global optimization method. For this purpose, the composite plate optimization problems have been solved for high stiffness and low coefficients of thermal and moisture expansion. Some of the results based on efficient global optimization solution have been verified by genetic algorithm, simulated annealing, and generalized pattern search solutions from the previous studies. The proposed optimization algorithm is also validated experimentally. After completing the design and optimization process, failure analysis of the optimized composites has been performed based on Tsai-Hill, Tsai-Wu, Hoffman, and Hashin-Rotem criteria.Article Citation - WoS: 32Citation - Scopus: 38Buckling Optimization of Composite Laminates Using a Hybrid Algorithm Under Puck Failure Criterion Constraint(SAGE Publications Inc., 2016) Deveci, Hamza Arda; Aydın, Levent; Artem, Hatice Seçil; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, an optimization procedure is proposed to find the optimum stacking sequence designs of laminated composite plates in different fiber angle domains for maximum buckling resistance. A hybrid algorithm combining genetic algorithm and trust region reflective algorithm is used in the optimization to obtain higher performance and improve the quality of solutions. As a novelty, Puck fiber and inter-fiber failure criteria are directly implemented to the optimization problems as nonlinear function constraints, which have allowed more consistent and feasible results. The performance of the hybrid algorithm is demonstrated by comparing with the individual performances of genetic and trust region reflective algorithms via test problems from the literature. Also, a study is performed to exhibit the effectiveness of the selected failure criterion as constraint among the other common criteria. The proposed procedure is used to solve many problems including various design considerations. The results indicate that reliable stacking sequence designs can be achieved in specific configurations even for the composite plates subjected to superior buckling loads when Puck physically based (3D) failure theory is considered as a first ply failure constraint in the buckling optimization.Article Citation - WoS: 19Citation - Scopus: 19Comparison of Stochastic Search Optimization Algorithms for the Laminated Composites Under Mechanical and Hygrothermal Loadings(SAGE Publications Inc., 2011) Aydın, Levent; Artem, Hatice Seçil; Artem, Hatice Seçil; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe aim of the present study is to design the stacking sequence of the laminated composites that have low coefficient of thermal expansion and high elastic moduli. In design process, multi-objective genetic algorithm optimization of the carbon fiber laminated composite plates is verified by single objective optimization approach using three different stochastic optimization methods: genetic algorithm, generalized pattern search, and simulated annealing. However, both the multi- and single-objective approaches to laminate optimization have been used by considerably few authors. Simplified micromechanics equations, classical lamination theory, and MATLAB Symbolic Math toolbox are used to obtain the fitness functions of the optimization problems. Stress distributions of the optimized composites are presented through the thickness of the laminates subjected to mechanical, thermal, and hygral loadings.Article Citation - WoS: 7Citation - Scopus: 7Exact Solution and Dynamic Buckling Analysis of a Beam-Column System Having the Elliptic Type Loading(Springer Verlag, 2010) Artem, Hatice Seçil; Aydın, Levent; Artem, Hatice Seçil; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThis paper presents a closed form solution to the dynamic stability problem of a beam-column system with hinged ends loaded by an axial periodically time-varying compressive force of an elliptic type, i.e., a 1cn 2(τ, k 2) + a 2sn2(τ, k 2) + a 3dn2(τ, k 2). The solution to the governing equation is obtained in the form of Fourier sine series. The resulting ordinary differential equation is solved analytically. Finding the exact analytical solutions to the dynamic buckling problems is difficult. However, the availability of exact solutions can provide adequate understanding for the physical characteristics of the system. In this study, the frequency-response characteristics of the system, the effects of the static load, the driving forces, and the frequency ratio on the critical buckling load are also investigated. © 2010 Shanghai University and Springer-Verlag Berlin Heidelberg.Conference Object Citation - WoS: 5Citation - Scopus: 6Multiobjective Genetic Algorithm Optimization of the Composite Laminates as a Satellite Structure Material for Coefficient of Thermal Expansion and Elastic Modulus(Institute of Electrical and Electronics Engineers Inc., 2009) Aydın, Levent; Artem, Hatice Seçil; Artem, Hatice Seçil; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThis study considers multi-objective optimal design of the fiber reinforced symmetric-balanced laminated composites using genetic algorithms. MATLAB Genetic Algorithm and Direct Search Toolbox is used to obtain Pareto-optimal design for three different model problems. The objectives of the problems are to maximize the Young's moduli and minimize the coefficient of thermal expansion (CTE) simultaneously for 8 and 16 layered carbon/epoxy composites. Simplified micromechanics equations and classical lamination theory are used in order to obtain the fitness functions of the problems. Stress and strain distributions are presented through the thickness of the laminates for the optimized problems under mechanical and thermal loadings.Article Citation - WoS: 5Citation - Scopus: 7Axisymmetric Crack Problem of Thick-Walled Cylinder With Loadings on Crack Surfaces(Elsevier Ltd., 2008) Aydın, Levent; Artem, Hatice Seçil; Artem, Hatice Seçil; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThis study is concerned with the fracture of an infinite thick-walled cylinder. The inner surface of the cylinder is stress free and the outer is rigidly fixed. The cylinder having a ring-shaped crack located at the symmetry plane is subjected to distributed compressive load on its surfaces. The Hankel and Fourier transform techniques are used for the solution of the field equations. By applying the boundary conditions, the singular integral equation in terms of crack surface displacement derivative is derived. By using an appropriate quadrature formula, the integral equation is reduced to a system of linear algebraic equations. Numerical results are obtained for the stress intensity factors at the edges of the crack, surfaces of which are subjected to uniform, linear and parabolic load distributions.