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: 1Citation - Scopus: 1Reconfigurable Polyhedral Mechanisms Using Scissor-Like Elements with Cantellation Transformation Between Dual Geometries(Pergamon-Elsevier Science Ltd, 2025) Liao, Yuan; Kiper, Gokhan; Krishnan, SudarshanDeployable polyhedron mechanisms (DPMs) have garnered significant interest in architecture, aerospace, and robotics, where reconfigurable and space-efficient structures are crucial. This paper presents a tangential design method for DPMs using scissor-like elements (SLEs). Scissor units are placed along the edges of an equilateral polyhedron, tangential to its midsphere. This method enables the mechanisms to transform between a polyhedron and its dual, following the cantellation operation. Using screw theory, the kinematic properties of these mechanisms are analyzed. Results show that the DPMs exhibit 1-degree of freedom (DOF) under normal conditions and gain additional DOFs at multifurcation points, allowing for reconfigurable motion modes. Physical models based on various geometries, including Platonic, Archimedean, Johnson, and Catalan solids, help to validate the method's feasibility. Observations indicate that this method is only applicable to equilateral supporting polyhedra. The transformability and reconfigurability observed in these mechanisms demonstrate the potential of this approach for applications in architecture, aerospace, and robotics.Article Citation - WoS: 1Citation - Scopus: 1Design Alternatives of Light Shelves Using Altmann Linkage(Solarlits, 2024) Atarer, Fulya; Korkmaz, Koray; Kiper, GokhanThis paper proposes a novel new light shelf design with Altmann linkage using its kinetic principles: geometry and rotational angles. As previous studies explain a light shelf's design in two ways: static and movable, the proposed one in this study has the potential to track the path of the sun due to its diagonal movement. The primary purpose is to direct the light shelf to intermediate directions, such as southeast and southwest, by utilizing the geometric properties of the Altmann linkage. The study explains how to dimension the links, calculate rotation angles, and model this device in Relux to test its daylight performance on specific dates in a year. A total of nine variations were analyzed during the three phases of design. They include shelf forms such as a rectangle, two rectangles, two squares, and varying link lengths, which define the distance to the windowsill. The final set of variations with two-square forms moving west and east successfully satisfied with sDA values as 71.52%, 72.99% (w), 75.92% (e); with ASE values as 8.83%, 8.56% (w), and 8.22% (e). This best design of Altmann linkage would be beneficial as an adaptive fa & ccedil;ade module that can direct daylight inside and achieve proper shading throughout the day and year. (c) 2024 The Author(s). Published by solarlits.com. This is an open access article under the CC BY license (https://creativecommons.org/licenses/by/4.0/).Book Part Citation - WoS: 1Citation - Scopus: 1A Historical Review of Polyhedral Linkages(Springer, 2024) Kiper, GökhanPolyhedral linkages are linkages that resemble polyhedral shapes at different configurations. This paper summarizes the necessary geometrical fundamentals of polyhedral geometry and presents a historical and critical review of the polyhedral linkage designs available in the literature. Basic definitions of polyhedral geometry and operations are needed to comprehend and design polyhedral linkages. First, early works on polyhedral linkages are presented, where flexible polyhedra with rigid faces and flexible edges are issued. The final part is reserved to conformal polyhedral linkages, which go through shape transformations while plane, dihedral and solid angles are preserved. Conformal polyhedral linkages are examined in four categories: 1) Jitterbug-like linkages with screwing polygonal links connected to each other with dihedral angle preserving links, 2) polyhedral linkages with planar kinematic chains in radial motion planes, 3) polyhedral linkages with planar kinematic chains on faces, that are connected to each other with dihedral angle preserving links, and 4) other conformal polyhedral linkages. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.Article Citation - WoS: 12Citation - Scopus: 13Mobility Analysis of Tripod Scissor Structures Using Screw Theory(Pergamon-elsevier Science Ltd, 2024) Liao, Yuan; Kiper, Gokhan; Krishnan, SudarshanMechanisms consisting of spatial scissor units have different kinematic behaviors than those of planar scissors. However, their kinematics, especially the mobility analysis, has not received enough attention. Two types of deployable asseblies are analyzed in this paper, namely the translational and mirrored assemblies. Both the assemblies are made of tripod scissor units, and their instantaneous mobility are examined using screw theory. The study starts on the configuration where all the members have the identical deployment angle. Firstly, the geometric property of each assembly was studied. Then, screw-loop equations were developed based on graph theory and closure equations. Finally, the mobility of each assembly was computed using linear algebra. Following the analysis, physical prototypes were constructed to validate the results, and several different motion modes were obtained for the translational assembly. The analysis reveals different kinematic behaviors of the two assemblies. In the given configuration, the translational assemblies have four instantaneous degrees of freedom, while the mirrored assemblies have only a single instantaneous degree of freedom.Article Citation - WoS: 19Citation - Scopus: 20A 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, KorayWhen 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.