Elastik Konsol Kirişlerin Büyük Deformasyon Analizi

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2015Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2015Bu çalışma kapsamında elastik konsol bir kirişin statik analizi Euler-Bernoulli eşitlikleri kullanılarak yinelemeli bir yöntemle yapılmıştır. Bu amaçla kiriş eşit uzunlukta parçalara bölünmüş ve ötelenmelerin hesabında, bu parçalar üzerindeki dönmelerin doğrusal değiştiği kabulü yapılmıştır. Başlangıçta kirişe verilen yükün kirişte oluşturduğu şekil değiştirmeler belirlenmiş, şekil değiştirmiş kirişe tekrar aynı yükler etki ettirilerek şekil değiştirmeler doğrusal olmayan şekilde tekrar belirlenmiştir. Bu işlem şekil değiştirme sonuçları yeteri kadar birbirine yaklaştığında bitirilerek kirişin gerçek şekil değiştirmesi bulunmuştur. Yineleme işlemi Ms Excel programlarında yapılmıştır.In the context of this study, structural analysis of an elastic cantilever has been conducted using an iterative method based on Euler-Bernouilli equations. For this purpose, the beam has been considered to be divided into elements of equal length and the rotational angles have been assumed to be linearly changing over these elements in computing the elastic curve. At the beginning, the deformations caused by the loads acting on the structure is determined, and then by application of the loads on the deformed system, the new deflections are re-calculated. This procedure is repeated until stabilization of deflections and rotations. The iterative process has been conducted using MS Excel

Dönmeye Karşı Kontrol Altına Alınmış Basit Mesnetli Çubukların Stoke Dönüşümü Yardımıyla Burkulma Analizi

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2015Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2015Bu çalışmada eksenel yüklenmiş basit mesnetli bir kirişin burkulma yüklerinin tespiti için yerel bir analitik yöntem geliştirilmiştir. Ayrıca kiriş uçlarından dönmeye karşı engelleyici yaylar ile sabitlenmiştir. Çalışmada Euler-Bernoulli kiriş teorisi kullanılmıştır. İlk olarak literatürde çok iyi bilinen Euler-Bernoulli kiriş teorisinin denklemi eksenel yükler altında verilmiştir. Analitik genel çözümlerin elde edilmesi için yer değiştirme fonksiyonu Fourier sinüs serisi seçilmiştir. Fourier sinüs serisinin seçilmesinin kirişin basit mesnetli olması ile bir ilgisi bulunmamaktadır. Literatürdeki çalışmalarda basit mesnetli kirişlerin sınır koşullarını sağladığı için genellikle Fourier sinus serileri kullanılmaktadır. Mesnetlerde dönmeye karşı yaylar kullanıldığı için; sınır koşullarında serbestlik sağlaması bakımından Stoke dönüşümü uygulanmıştır. Bu dönüşümün yapılmasının temel amacı yay sabitlerine verilecek değerlerde esneklik sağlamasıdır.This paper presents an analytical method for buckling analysis of simply supported beam with rotational restraints at both ends. Euler Bernoulli theory is used. The lateral displacement function is sellected by a Fourier sine series. Stokes’ transformation is applied to boundary conditions in order to construct the coefficient matrix. This application gives more flexibility for buckling analysis of beams with different boundary conditions. Comparisons are performed to validate present analytical method

The state of the art development of AHP (1979-2017): A literature review with a social network analysis

Although many papers describe the evolution of the analytic hierarchy process (AHP), most adopt a subjective approach. This paper examines the pattern of development of the AHP research field using social network analysis and scientometrics, and identifies its intellectual structure. The objectives are: (i) to trace the pattern of development of AHP research; (ii) to identify the patterns of collaboration among authors; (iii) to identify the most important papers underpinning the development of AHP; and (iv) to discover recent areas of interest. We analyse two types of networks: social networks, that is, co-authorship networks, and cognitive mapping or the network of disciplines affected by AHP. Our analyses are based on 8441 papers published between 1979 and 2017, retrieved from the ISI Web of Science database. To provide a longitudinal perspective on the pattern of evolution of AHP, we analyse these two types of networks during the three periods 1979?1990, 1991?2001 and 2002?2017. We provide some basic statistics on AHP journals and researchers, review the main topics and applications of integrated AHPs and provide direction for future research by highlighting some open questions

The state of the art development of AHP (1979-2017): a literature review with a social network analysis

Although many papers describe the evolution of the analytic hierarchy process (AHP), most adopt a subjective approach. This paper examines the pattern of development of the AHP research field using social network analysis and scientometrics, and identifies its intellectual structure. The objectives are: (i) to trace the pattern of development of AHP research; (ii) to identify the patterns of collaboration among authors; (iii) to identify the most important papers underpinning the development of AHP; and (iv) to discover recent areas of interest. We analyse two types of networks: social networks, that is, co-authorship networks, and cognitive mapping or the network of disciplines affected by AHP. Our analyses are based on 8441 papers published between 1979 and 2017, retrieved from the ISI Web of Science database. To provide a longitudinal perspective on the pattern of evolution of AHP, we analyse these two types of networks during the three periods 1979–1990, 1991–2001 and 2002–2017. We provide some basic statistics on AHP journals and researchers, review the main topics and applications of integrated AHPs and provide direction for future research by highlighting some open questions

Computation of Nonunique Solutions for Trusses Undergoing Large Deflections

Determination of nonunique configurations of structures is a problem which cannot be treated readily using classical methods of analysis. In the literature, these kinds of problems are tackled for some simple problems, like trusses with a small number of joints and members, and with specially designed approaches. The recent method of analysis called Total Potential Optimization using Metaheuristic Algorithms (TPO/MA), on the other hand, provides an efficient tool for dealing with these kinds of problems, practically without recourse to any special arrangement. In this analysis, using Harmony Search as the metaheuristic algorithm, large truss structures with linear elastic members are investigated under large deflections as to the existence of more than one solution. The results have shown that for the two examples investigated, a tower truss with 25 members and a dome truss with 24 members, nonunique configurations do exist at quite unexpected levels of loads, and that only one of them can be found with normal applications of the well-known Finite Element method