Mechanical Engineering / Makina Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/4129

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Scopus Q: search.filters.scopusQuartile.Q1Subject: search.filters.subject.Deployable structures

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  • 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.
  • Article
    Design, Prototyping and Tests of a Rollable Ramp for Temporary Use
    (Springer, 2021) Doğan Kumtepe, Elvan; Kiper, Gökhan
    Portable ramps, used generally by wheelchair users, offer temporary solution to increase accessibility and mobility. Preferably these ramps should be compact and lightweight for ease of handling and storage. Different types of portable ramps in the market that are used by wheelchair users are generally made of aluminum and require several improvements, especially in terms of lightweight and compactness. Based on wheelchair users’ inclinations a compact and lightweight rollable ramp is designed in this study. A parametric model of the links of the ramp are derived and the rolled geometry is optimized using convex hull and smallest enclosing circle algorithms. The side bars of the links are designed and manufactured from aluminum and the load-bearing panels are manufactured from sandwich composite structures with honeycomb core. Strength calculations are performed analytically and also with finite-element analysis. After the design is finalized, a prototype is manufactured. The designed ramp is 15.4% more compact and has 18.9% less weight compared to the best rival product available in the market. Load tests and functional tests are performed with voluntary wheelchair users. Several positive feedbacks are received from the participants about the ramp being practical, easy to use and store, lightweight, advantage of the anti-slip surface.
  • Article
    Citation - WoS: 59
    Citation - Scopus: 66
    A Novel Concept of Convertible Roofs With High Transformability Consisting of Planar Scissor-Hinge Structures
    (Elsevier Ltd., 2010) Akgün, Yenal; Gantes, Charis J.; Kalochairetis, Konstantinos E.; Kiper, Gökhan
    In this paper, a new adaptive scissor-hinge structure is introduced, which can be converted by means of actuators between a multitude of curvilinear arch-like shapes, where it can be stabilized and carry loads. The key point of this new structure is the proposed Modified Scissor-Like Element (M-SLE). With the development of this element, it becomes possible to change the geometry of the whole system without changing the dimensions of the struts or the span. The proposed scissor-hinge structure discussed here is planar, but it is also possible to combine structures in groups to create spatial systems. After outlining the differences of the proposed structure with existing designs, the dimensional properties of the M-SLE are introduced. Then, geometric principles and shape limitations of the whole structure are explained. Finally, structural analysis of the structure in different geometric configurations is performed, in order to discuss stiffness limitations associated with the advantage of increased mobility. © 2010 Elsevier Ltd.