Architecture / Mimarlık

Permanent URI for this collectionhttps://hdl.handle.net/11147/24

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Author: search.filters.author.Akgün, Yenal

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Now showing 1 - 10 of 12
  • Book Part
    Scherengestänge als elemente adaptiver morphologien
    (Birkhäuser, 2020) Akgün, Yenal; Maden, Feray; Gür, Şebnem; Kiper, Gökhan; Korkmaz, Koray; Aktaş, Engin; Yar Uncu, Müjde
    Zu allen Zeiten haben Menschen versucht, flexible Gebäude zu bauen, die sich ständig verändernden Anforderungen und Umweltbedingungen anpassen. Die Einbeziehung von Bewegung in die Architektur ist der Versuch, auf veränderliche Umstände mit neuen Lösungen zu reagieren. Das Konzept der Bewegung ist in der Tat nicht neu für die Architektur. Die Wurzeln gehen bis in die Antike zurück. Einfache, mit flexiblen Außenhäuten gebaute Nomadenzelte können als das erste Beispiel für adaptive Strukturen angesehen werden, die zum Schutz vor extremen Umweltbedingungen dienten.1 Die zum Abdecken des Daches im Colosseum von Rom verwendeten Leinwandbahnen sind ein weiteres Beispiel. Sie bildeten Markisen, die nicht nur Sonnenschutz boten, sondern für die Zuschauer durch ihr Durchhängen zur Mitte hin auch eine Brise einfingen.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 5
    Loop Based Classification of Planar Scissor Linkages
    (Springer, 2022) Kiper, Gökhan; Korkmaz, Koray; Gür, Şebnem; Yar Uncu, Müjde; Maden, Feray; Akgün, Yenal; Karagöz, Cevahir
    Scissor linkages have been used for several applications since ancient Greeks and Romans. In addition to simple scissor linkages with straight rods, linkages with angulated elements have been introduced in the last decades. In the related literature, two methods have been used to design scissor linkages, one of which is based on scissor elements, and the other is based on assembling loops. This study presents a systematic classification of scissor linkages as assemblies of rhombus, kite, dart, parallelogram and anti-parallelogram loops using frieze patterns and long-short diagonal connections. After the loops are replicated along a curve as a pattern, the linkages are obtained by selection of proper common link sections for adjacent loops. The resulting linkages are analyzed for their motions and they are classified as realizing scaling deployable, angular deployable or transformable motion. Some of the linkages obtained are novel. Totally 10 scalable deployable, 1 angular deployable and 8 transformable scissor linkages are listed. Designers in architecture and engineering can use this list of linkages as a library of scissor linkage topologies.
  • Conference Object
    Citation - WoS: 1
    Citation - Scopus: 2
    Structural Comparison of Scissor-Hinge Linkages
    (CRC Press, 2019) Maden, Feray; Akgün, Yenal; Yücetürk, Kutay; Aktaş, Engin; Yar Uncu, Müjde; Mitropoulou, C.
    Deployable structures can deploy from a compact to an expanded configuration by changing their sizes. The behaviors of these structures depend on some parameters such as geometric shape, member sizes and kinematic properties. To provide the deployment, not only the arrangements of structural members but also some restrictions must be considered. Moreover, contiguous members of the structures must let the large rotations to provide the transformation between different geometric forms from fully folded to fully deployed configurations. These requirements have an important impact on the fundamental properties of the structures related with structural performance, such as stiffness and strength. In this paper, stiffness of different scissor-hinge linkages are analyzed and compared. These linkages cover the same span with almost the same geometry and have the unit elements with same size and same weight. However, the geometry of unit elements is different from each other. The paper investigates the effect of this difference on the stiffness of whole system. © 2019 Taylor & Francis Group, London.
  • Article
    Citation - WoS: 19
    Citation - Scopus: 20
    A Critical Review on Classification and Terminology of Scissor Structures
    (Int. Association for Shell and Spatial Structures, 2019) Maden, Feray; Akgün, Yenal; Kiper, Gökhan; Gür, Şebnem; Yar, Müjde; Korkmaz, Koray
    When the existing literature on the research of scissor structures is thoroughly investigated, it is seen that different researchers use different terminologies and classifications especially for the definition of the primary units and the motion type. Some of the studies define the whole geometry based on the geometric properties of the primary scissor units and the unit lines while some other studies define it according to the loops. All these studies use different names for similar elements. This article aims to review the literature on the classification and terminology of scissor structures and represent the state of art on the studies. Tables are represented showing all approaches in the literature. In addition, the article criticizes the missing points of each terminology and definition, and proposes some new terminology. In order to arrive at this aim, different definitions of the primary scissor units and motion types used in key studies in the literature are investigated thoroughly. With several examples, it is demonstrated that naming the scissor units according to the resulting motion type might be misleading and it is better to specify the motion type for the whole structure. A classification for transformation of planar curves is presented.
  • Book Part
    Scissor Linkages in the Design of Adaptive Morphologies
    (Walter de Gruyter GmbH, 2019) Akgün, Yenal; Maden, Feray; Gür, Şebnem; Kiper, Gökhan; Korkmaz, Koray; Aktaş, Engin; Yar Uncu, Müjde
    Scissor linkages are capable of forming various expandable structures. Architects can benefit from this type of linkage especially for designing adaptive, movable, transformable shell structures and deployable beam-like structures. Product designers may benefit as well. The two different methods described here convey the basic design approaches. The unit-based method is very effective for obtaining primary geometries like a dome, arch, circle or line, using serial multiplications and arrays of one of the scissor unit types presented here. The loop assembly method is more convenient when a final form, be it straight or free-form, is the main point of departure. In this case, unlike in the unit-based method, it is not necessary to opt for a specific scissor unit type and its dimensional constraints from the beginning. Designers can choose a type and number of loops and then define the scissor units following the loop sides. Since deployability is guaranteed by applying this method, the architect is free to choose the loop type most suitable for the functional needs and aesthetic concerns of the specific design. With the loop assembly method all loop alternatives can be assembled to scissor structures, their possible motions can be tested and evaluated in a short time, whereas the unit-based method is limited to a single type of motion that a specific unit can provide.
  • Article
    Citation - Scopus: 11
    A Novel Planar Scissor Structure Transforming Between Concave and Convex Configurations
    (WITPress, 2017) Yar, Müjde; Korkmaz, Koray; Kiper, Gökhan; Maden, Feray; Akgün, Yenal; Aktaş, Engin
    In this paper, a novel two-dimensional scissor structure that transforms between concave and convex configurations is presented. The structure is designed by a method of assembling kite or anti-kite loops in the flat configuration. Angulated units are generated from the assembled loops. Finally, a new angulated scissor unit is introduced in order to design the novel scissor structure.
  • Conference Object
    Citation - WoS: 3
    Citation - Scopus: 3
    Design of Adaptive Structures by Kinematic Synthesis of Mechanisms
    (CRC Press, 2013) Akgün, Yenal; Maden, Feray; Korkmaz, Koray
    Parallel to the development of material science and computer technologies, adaptive structures and smart building components have become the demand of contemporary architecture. However, in order to design adaptive systems, basic knowledge on kinematic synthesis is needed. This paper introduces the fundamental principles of the kinematic synthesis of mechanisms and expresses the potential structural uses of common mechanisms. For this purpose, main concepts of the mechanisms are introduced and types of kinematic synthesis are explored by the help of innovative examples. In this context, firstly, type synthesis methods are explained. Second step covers the path generation rules, and the final step includes the design of multi-loop and chain mechanisms. During the explanation of the aforementioned principles, innovative adaptive structures which are designed by the authors are introduced as well. These structures are all derived from common planar and spatial mechanisms such as four-bar linkages, Watt mechanisms, scissor systems, Bennett linkages and different multi-loop mechanisms.
  • Conference Object
    Citation - Scopus: 2
    Design of Reconfigurable Doubly-Curved Canopy Structure
    (CRC Press, 2013) Maden, Feray; Korkmaz, Koray; Akgün, Yenal
    In this paper, a new reconfigurable doubly-curved structure has been developed for a canopy roof. The proposed structure can transform itself to various configurations according to the activity and user requirements. It not only changes its shape from a planar geometry to doubly-curved geometries by means of actuators, but also becomes stable and carries loads. The main differences between proposed structure and similar deployable bar structures are that the proposed structure is more flexible with 2DoF and it requires less number of bars and joints. To obtain the doubly-curved geometry, a novel method has been introduced. After discussing the kinematic behavior of the system, a set of structural analyses are performed in three different geometric configurations of the proposed structure.
  • Article
    Citation - WoS: 89
    Citation - Scopus: 118
    A Novel Adaptive Spatial Scissor-Hinge Structural Mechanism for Convertible Roofs
    (Elsevier Ltd., 2011) Akgün, Yenal; Gantes, Charis J.; Sobek, Werner; Korkmaz, Koray; Kalochairetis, Konstantinos E.
    In this paper, a new adaptive deployable spatial scissor-hinge structural mechanism (SSM) is introduced, which can be converted by means of actuators between a multitude of arch-like, dome-like and double curved shapes, where it can be stabilized and carry loads. This novel SSM is a spatial extension of a planar SSM introduced recently that can achieve a wide range of planar geometries. Main differences of the proposed structural mechanism from current deployable structures are the new connection type of the primary units and the proposed modified spatial scissor-like element (MS-SLE). With the development of this new connection detail and the modified element, it becomes possible to change the geometry of the whole system without changing the dimensions of the struts or the span. After presenting some disadvantages of current deployable structures and outlining the main differences of the proposed spatial SSM with existing examples, the dimensional properties of the primary elements are introduced. Then, geometric principles and shape limitations of the whole structure are explained. Finally, structural analyses of a typical structure in two different geometric configurations are performed, in order to discuss stiffness limitations associated with the advantage of increased mobility.
  • Article
    Citation - WoS: 75
    Citation - Scopus: 95
    A Review of Planar Scissor Structural Mechanisms: Geometric Principles and Design Methods
    (Taylor and Francis Ltd., 2011) Maden, Feray; Korkmaz, Koray; Akgün, Yenal
    This study deals with a review of planar scissor structural mechanisms (SSMs) and reports on how they can be easily transformed from a stowed to a deployed configuration. These mechanisms have an important transformation capacity of their extension and rotation properties, and many examples have been proposed that vary in size, type and geometry. Although there are many studies dealing with designing new planar or spatial SSMs and their calculation methods, there is no systematic study demonstrating the basic typologies, geometric principles, design rules and constraints of such SSMs. Further, current calculation methods are based on the inductive approach in which the dimension of one scissor unit (SU) is given, but the span of the whole structure is found later according to the number of SUs that are used to assemble the structure. However, this approach is not convenient for architectural applications, because it requires a deductive approach in which the dimensions and required number of SUs are calculated according to defined span length. On the basis of this concept, this article, first, analyses the geometric design of SSMs systematically in terms of their possible configurations and then develops trigonometric calculation methods for different types of SSMs, using a deductive approach.