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Öğe Advanced energy-based analyses of trusses employing hybrid metaheuristics(Wiley, 2019) Bekdas, Gebrail; Kayabekir, Aylin Ece; Nigdeli, Sinan Melih; Toklu, Yusuf CengizTotal potential optimization using metaheuristic algorithm (TPO/MA) is an alternative method in structural analyses, and it is a black-box application for nonlinear analyses. In the study, an advanced TPO/MA using hybridization of several metaheuristic algorithms is investigated to solve large-scale structural analyses problems. The new generation algorithms considered in the study are flower pollination algorithm (FPA), teaching learning-based optimization, and Jaya algorithm (JA). Also, the proposed methods are compared with methodologies using classic and previously used algorithms such as differential evaluation, particle swarm optimization, and harmony search. Numerical investigations were carried out for structures with four to 150 degrees of freedoms (design variables). It has been seen that in several runs, JA gets trapped into local solutions. For that reason, four different hybrid algorithms using fundamentals of JA and phases of other algorithms, namely, JA using Levy flights, JA using Levy flights and linear distribution, JA with consequent student phase, and JA with probabilistic student phase (JA1SP), are developed. It is observed that among the variants tried, JA1SP is seen to be more effective on approaching to the global optimum without getting trapped in a local solution.Öğe Analysis of Plane-Stress Systems via Total Potential Optimization Method Considering Nonlinear Behavior(Asce-Amer Soc Civil Engineers, 2020) Toklu, Yusuf Cengiz; Kayabekir, Aylin Ece; Bekdas, Gebrail; Nigdeli, Sinan Melih; Yucel, MeldaAs an alternative structural analysis method, total potential optimization using metaheuristic algorithms (TPO/MAs) has been demonstrated to be very effective, especially in nonlinear cases, for trusses and trusslike systems such as tensegric structures and cable networks. A recent study showed that TPO/MAs also can be applied successfully to plane-stress problems with linear constitutive equations. The present study enlarged the application area of TPO/MAs to the analysis of plates for plane-stress cases with nonlinear stress-strain equations. A relevant formulation was developed and used to solve five problems. Because TPO/MAs can be applied by using different metaheuristic algorithms, a number of them, some hybrid, were used, and they were compared among themselves and with finite-element solutions. The final example was a tunnel problem with 150 nodes, i.e., with 265 unknowns. This problem also was solved via hybrid algorithms. Several proposals for future research are listed. (c) 2020 American Society of Civil Engineers.Öğe A Novel Hybrid Harmony Search Approach for the Analysis of Plane Stress Systems via Total Potential Optimization(MDPI, 2020) Toklu, Yusuf Cengiz; Kayabekir, Aylin Ece; Bekdaş, Gebrail; Niğdeli, Sinan MelihBy finding the minimum total potential energy of a structural system with a defined degree of freedoms assigned as design variables, it is possible to find the equilibrium condition of the deformed system. This method, called total potential optimization using metaheuristic algorithms (TPO/MA), has been verified on truss and truss-like structures, such as cable systems and tensegric structures. Harmony Search (HS) algorithm methods perfectly found the analysis results of the previous structure types. In this study, TPO/MA is presented for analysis of plates for plane stress members to solve general types of problems. Due to the complex nature of the system, a novel hybrid Harmony Search (HHS) approach was proposed. HHS is the hybridization of local search phases of HS and the global search phase of the Flower Pollination Algorithm (FPA). The results found via HHS were verified with the finite element method (FEM). When compared with classical HS, HHS provides smaller total potential energy values, and needs less iterations than other new generation metaheuristic algorithms.Öğe Tranfer function amplitude minimization for structures with tuned mass dampers considering soil-structure interaction(Elsevier Sci Ltd, 2019) Bekdas, Gebrail; Kayabekir, Aylin Ece; Nigdeli, Sinan Melih; Toklu, Yusuf CengizThe optimum tuned mass damper (TMD) parameters rely on the superstructure's natural frequency, which, in turn, depends on the soil condition under the structure. Thus, the consideration of soil conditions in determination of the optimum TMD parameters is necessary. In this study, a methodology is proposed for the determination of TMD parameters considering soil-structure interaction. The objective function in the study is the acceleration transfer function. For the stochastic optimization problem, several metaheuristic algorithms, namely harmony search, flower pollination algorithm, teaching, learning based optimization, Jaya algorithm and two new versions of it are employed. Numerical experiments on methodology are presented for a 40-story structure considering soil-structure interaction. It is shown through applications that, especially for soft soils, the use of TMDs is an effective way to damp structural vibrations resulting from seismic sources and consideration of the base stiffness is effective on the optimum TMD parameters. Comparisons among the results obtained through different metaheuristic algorithms are also given.