Mechanical Engineering / Makina Mühendisliği

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

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The Architectural Application of Altmann Linkage as a Light Shelf
(Yaşar Üniversitesi, 2020) Atarer, Fulya; Kazanasmaz, Zehra Tuğçe; Korkmaz, Koray; Kiper, Gökhan
Daylight and its penetration in a room are significant concerns in architectural design. Light shelves are necessary to control daylight on fenestration. In the literature, there are many daylight controller systems such as light shelves. This paper presents the possibility of using Altmann linkage as the basis of constructing such a light shelf in rectangular form. It is basically a horizontal or inclined device, having high reflectance on the upper surface to control and redistribute daylight, placed above the eye-level in the fenestration system. The performance of a light shelf varies according to its dimensions, distance to window sill, distance to window head, its rotation angle and orientation in terms of daylight efficiency and visual comfort. It is also used to provide shading. This system can be internal or external and being static or movable. A light shelf presents its maximum efficiency in south facing façades receiving higher direct sun incident angles in medium latitudes of northern hemisphere. The aim of this study is to explain the design process of an adaptable Altmann light shelf including dimensioning the links in a rectangular form, calculating rotation angles, modelling this device in Relux to test its daylight performance. Regarding the Altmann geometries, three variations are set while changing its distance to window sill. The aim is to test illuminance and uniformity. Relux calculates illuminance and uniformity at four significant dates and three chosen hours for each one, to obtain the best design.
Citation - WoS: 18
Citation - Scopus: 19
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.
Citation - Scopus: 9
Design Alternatives of Network of Altmann Linkages
(WITPress, 2017-06) Atarer, Fulya; Korkmaz, Koray; Kiper, Gökhan
This paper presents a method of building deployable network assemblies derived from the single degree of freedom (DoF) over constrained Altmann linkage as a basic module. The method is based on assembling linkages with common links and joints or overlapping with extra R or 2R joints. New loops are emerged with overlapping method. The networks created have a single DoF, are over-constrained and have both fully deployed and folded configurations. The computer-aided models (CAD) are used to demonstrate these derived novel mechanisms.
Design of a Reconfigurable Deployable Structure
(2014-11-24) Gürcü, Fulya; Korkmaz, Koray; Kiper, Gökhan
This paper introduces a reconfigurable mechanised structure design composed of planar linkage units. The alternative forms that a linkage can be constructed with the same links and connections are called configurations or assembly modes of the linkage. During its motion, the linkage may pass from one assembly mode to another, which is called reconfiguration or assembly mode change. The reconfigurable structure presented in this paper is a single DOF multi-loop mechanised structure which has more than two configurations. Design and position analysis of the mechanism are implemented in Microsoft Excel environment. The link lengths can be varied in this environment and the structure can be simulated by changing input joint parameters. The mechanised reconfigurable structure can be used as a multifunctional canopy which can take any form in a few minutes for urgent needs after disasters, military purpose or public needs.
Citation - WoS: 6
Citation - Scopus: 5
Design of Anti-Parallelogram Loop Assemblies
(Int. Association for Shell and Spatial Structures, 2019) Gür, Şebnem; Korkmaz, Koray; Kiper, Gökhan
Scissor mechanisms are frequently used for deployable structures and many studies have been conducted on the subject. Most of the studies consider scissor units as modules in the design process. An alternative approach is to utilize loops as the modules for design. In this paper, the design alternatives of single degree-of-freedom planar linkages comprising anti-parallelogram loops using the loop assembly method is presented. First, scissor mechanisms are reviewed. Next, the types of four-bar loops and the resulting linkages in the literature are introduced and those which are yet to be explored, anti-parallelogram being one of them, are identified. Then the loop assembly method and the examples in the literature are reviewed. As a method to form as many alternatives as possible, symmetry operations are proposed. Suitable frieze symmetry groups utilized for obtaining the assemblies are explained and the anti-parallelogram loop patterns are derived. Next, the single degree-of-freedom linkages are obtained from the loop assemblies. Finally, a selection of the resulting linkages with novel properties are presented. This study shows that loop assemblies are efficient in systematic type synthesis of scissor linkages, some types of which could not be foreseen by using units as modules.
Citation - WoS: 1
Citation - Scopus: 1
Design of Demountable Reciprocal Frames With New Geometric Properties
(Int. Association for Shell and Spatial Structures, 2022-09) Özen, Gülçin; Kiper, Gökhan; Korkmaz, Koray
This study aims to develop missing geometric knowledge for demountable reciprocal frames (RF). While designing a demountable RF, one should know the initial, in-process and final form of the RF. These processes require some specific geometric knowledge. There are some deficiencies about geometric properties in the previous studies about demountable RFs. In this study, the positions and the orientations of the nexors are found by using the Denavit-Hartenberg parameters. This information gives where the joints are placed, how they are oriented and take position according to one another. Besides, the influence of engagement length on the fan height and the base edge are analyzed. Thereby one will be able to find out how much space the RF covers with the known base edge. With the geometric knowledge obtained from this study, demountable RFs having different engagement lengths can be produced with the same nexors.
Citation - WoS: 6
Citation - Scopus: 8
The Effect of Spatial Interventions on Historic Buildings' Indoor Climate (case Study: Tire Necip Paşa Library, Izmir-Turkey)
(Elsevier Ltd., 2017) Coşkun, Turgay; Gülhan, Özcan; Şahin, Cem Doğan; Durmuş Arsan, Zeynep; Gökçen Akkurt, Gülden
The indoor climate of historic libraries should meet rigorous requirements related to human thermal comfort and conservation of books, manuscripts and cultural proper-ties. Paper based collections in historic libraries can be deteriorated chemically, mechanically and biologically because of inadequate indoor climate conditions. In this paper, Necip Paşa Library, the historic library located in Tire-Izmir, Turkey, was selected as a case study. The chemical, mechanical and biological degradation risks on the manuscripts were evaluated based on the indoor climate parameters measured for one year period. The Library, consisting of a main hall, a manuscript zone and an entrance hall, was modelled via the dynamic simulation software, Design Builder. Calibration of the model was conducted with respect to the measured indoor temperature and relative humidity values. The portico/Revak at the south facade of Library was converted into the entrance hall by wooden framed windows in 1930. To be able to see the effect of that intervention on the indoor climate (correspondingly on degradation risk of the manuscripts), a new model, namely semi-open model, was created and simulated. A remarkable change has not been observed on chemical degradation risk when the results of semi-open and existing library models were compared, while mechanical and biological degradation risks were less in semi-open model.
Citation - WoS: 6
Citation - Scopus: 9
Impact of Climate Change on Indoor Environment of Historic Libraries in Mediterranean Climate Zone
(Inderscience Enterprises, 2019) Turhan, Cihan; Durmuş Arsan, Zeynep; Gökçen Akkurt, Gülden
Most historic library buildings house valuable paper-based collections that are kept in unconditioned environments. This vulnerable cultural heritage is expected to be highly affected by climate change in the future. In this study, indoor microclimate of an unconditioned historic library, Necip Pasa Library (Izmir, Turkey) is analysed for existing conditions and future climate data. The measured and predicted indoor microclimate data from 'present' till 2080s are used to determine possible chemical degredation risk on library collection and human comfort. Comparison of periodic results of future climate data indicates an increase in temperature that could cause both an increase in chemical degredation risk on the library collection and a decline in thermal comfort conditions. Mitigation of climate change effects on library collection and human comfort requires taking some actions such as adding light and adaptive mechanical solutions.
Citation - WoS: 7
Citation - Scopus: 7
The Importance of Internal Heat Gains for Building Cooling Design
(Yıldız Teknik Üniversitesi, 2017) Coşkun, Turgay; Turhan, Cihan; Durmuş Arsan, Zeynep; Gökçen Akkurt, Gülden
This paper aims to investigate the effect of internal heat gains on the cooling load of a building. The house occupied by three adult men is selected as the case study for paper. The house is in the third floor of the apartment. The apartment has four flats and it has no insulation around the external walls. The heat dissipation from lighting devices, electrical equipment and the occupants are calculated by using the DesignBuilder v4 Beta release simulation program. The temperature of the house is observed during three weeks by using hobo data loggers and calibration of the measurements is made with respect to weather data file of the flat. Detailed schedule based on time of operation and occupancy is prepared to get more accurate results. Annual energy consumption and cooling load of the house is determined by using the dynamic simulation program.
Citation - WoS: 28
Citation - Scopus: 38
Investigation of Indoor Microclimate of Historic Libraries for Preventive Conservation of Manuscripts. Case Study: Tire Necip Paşa Library, Izmir-Turkey
(Elsevier Ltd., 2017-04) Şahin, Cem Doğan; Çoşkun, Turgay; Durmuş Arsan, Zeynep; Gökçen Akkurt, Gülden
Conservation of library collections requires an interdisciplinary approach. Dealing with the agents of deterioration via curative and preventive conservation methods has become a significant goal with new standards and norms in recent years. Preventive conservation aims indirect physical interventions such as climate control, good housekeeping and pest management. The aim of this study is to assess the degradation potential of indoor climate on valuable manuscripts that date back to 12th century, in a historic library in Tire-İzmir, Turkey. Through the study, first the library, namely Necip Paşa Library was continuously monitored by measurements of thermo-hygrometric parameters for one year. Then, the measured data were evaluated for the risk assessment based on the control classes of ASHRAE Chapter 21 to evaluate the mechanical, chemical and biological degradation risks. Finally, the conservation-oriented measures were proposed in order to keep the manuscripts under the better conditions. Results suggest that introducing a heating, ventilation and air-conditioning system to the building should be considered as the last option since natural hygrothermal behavior of the library gives reasonably sufficient evidences to prevent the manuscripts from degradations to some extent. Therefore, passive solutions should be given higher priorities not to disturb environmental past of the historic library.
Citation - WoS: 9
Citation - Scopus: 10
Kinematic Design of a Reconfigurable Deployable Canopy
(Springer Verlag, 2014-08-27) Kiper, Gökhan; Gürcü, Fulya; Korkmaz, Koray; Söylemez, Eres
A reconfigurable and deployable mechanism is proposed for a canopy which can also be used as a tent or a semi-open structure. The proposed single degree-of-freedom mechanism has four as-sembly modes. The conditions for deployment and reconfiguration of the mechanism are derived. These conditions impose three equality and two inequality constraints on the 11 design parameters of the mechanism. A virtual model of the mechanism is constructed in Excel for design and simulation purposes. A computational case study is presented.
Citation - WoS: 4
Citation - Scopus: 4
Loop Based Classification of Planar Scissor Linkages
(Springer, 2022-03) 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.
Citation - WoS: 56
Citation - Scopus: 64
A Novel Concept of Convertible Roofs With High Transformability Consisting of Planar Scissor-Hinge Structures
(Elsevier Ltd., 2010-09) 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.
A Novel Design Method of Deployable Semi-Regular Tessellated Surfaces With Plano-Spherical Units
(Int. Association for Shell and Spatial Structures, 2022-09) Maral, Mesude Oraj; Korkmaz, Koray; Kiper, Gökhan
The design of movable systems gives an opportunity to create transformable designs which respond to the environmental, functional, cultural, and aesthetical needs of today's architecture. This paper proposes a method for designing a family of deployable structures which can be applied to semi-regular tessellated planar surfaces such as roofs, walls, and shading devices. The generated modular approach and adaptability provides a wide usage area and various combinations for these designs. The regular convex polygon modules are designed as a network of the triangular units. The triangular unit is designed using Bennett's overconstrained plano-spherical linkage topology. The polygonal modules are assembled to each other in one-uniform semi-regular tessellations. The assembly of adjacent regular convex polygons in each tessellation is examined to find a proper solution for no collision during deployment and to properly fit a surface without any gaps or overlaps in the deployed position. The assembly method for creating 1-DoF deployable surfaces and mobility calculations for a unit, the polygonal modules, and the assemblies are computed, and motion studies are demonstrated with CAD models and exemplified for a square module for motion tests in a prototype.
Citation - Scopus: 11
A Novel Planar Scissor Structure Transforming Between Concave and Convex Configurations
(WITPress, 2017-06) 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.
Citation - WoS: 23
Citation - Scopus: 26
On the Relation Between Architectural Considerations and Heating Energy Performance of Turkish Residential Buildings in Izmir
(Elsevier Ltd., 2014-04) Kazanasmaz, Zehra Tuğçe; Erlalelitepe Uygun, İlknur; Gökçen Akkurt, Gülden; Turhan, Cihan; Ekmen, Kenan Evren
By considering the energy efficiency legislations among the European Union, Turkey is responsible to provide regulations to comply for the latest European Energy Performance of Buildings Directive 2010/31/EC. New legislation in Turkey requires information about the evaluation of energy performance of existing buildings. This study aimed to determine energy performance of residential buildings in Izmir, regarding significant relationships between their performance and architectural configuration through statistical analysis. The focus was on the heating energy consumption due to Energy Efficiency Law (2007) and Building Energy Performance Regulation (2008), and Standard Assessment Method for Energy Performance of Dwellings (KEP-SDM). This energy performance assessment method was based on Turkish standard TS 825, and European standard EN ISO 13790. It is known that architectural configuration of buildings and design norms have impact on energy performance of buildings. However, emphasis was given on significant values of architectural considerations through certain area-based ratios. The levels of these ratios were matched with the levels of energy consumption. By this, the consideration was to take early-precautions against high energy consumptions in the early design stage and to enhance legislation by adding recommendations of concrete architectural values. These would assist to predict the level of energy performance in the early design phase. Findings would provide feedback information on the residential building stock in İzmir, Turkey.
Radially Expandable Ring-Like Structure With Antiparallelogram Loops
(Azerbaijan Technical University, 2017-09-11) Gür, Şebnem; Korkmaz, Koray; Kiper, Gökhan
As they constitute a substantial percent of deployable structures, scissor mechanisms are widely studied. This being so, new approaches to the design of scissor mechanisms still emerge. Usually design methods consider the scissor elements as modules. Alternatively, it is possible to consider the loops as modules. In this paper, loop assembly method is used such that antiparallelogram loops are placed along a circle, to construct a deployable structure. The research shows that it is possible to construct radially deployable structures with identical antiparallelogram loops with this method. Then kinematic and geometrical properties of the construction are analyzed. It is found out that the links of such a structure turn out to be similar generalised angulated elements. Furthermore, similar loops are used for the construction and deployable rings are obtained.
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.
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.
Citation - WoS: 1
Citation - Scopus: 2
Synthesis of Scalable Planar Scissor Linkages With Anti-Parallelogram Loops
(Springer Verlag, 2019) Gür, Şebnem; Karagöz, Cevahir; Kiper, Gökhan; Korkmaz, Koray
Scissor linkages are commonly used as mechanisms for scaling objects. They constitute a significant portion of deployable structures. Since 1960s many researchers sought to form novel structures using the scissor units. In 1990s Hoberman brought a new perspective to the field when he used the loops, not the units to form linkages. Starting from mid 2000s, other researchers joined into this new approach of design. One of the latest researches presented a design for scaling a circular forms with anti-parallelogram loops. This study shows that an anti-parallelogram loop assembly can also be used for scaling planar curves with variable curvature.