Koray Korkmaz

A review of planar scissor structural mechanisms: geometric principles and design methods

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.

Design of a 2-DOF 8R Linkage for Transformable Hypar Structure

Double curved geometries including hyperbolicparaboloids (hypars) have become a trend in contemporary architecture. However, most of the constructed architectural examples of the hypars are static and cannot offer any form variability. In this paper, a 2-DOF 8 R linkage mechanism is introduced to buildtransformable hypar structures. It is inspired from the basic design principles of Bennett linkage. By its distinctive connection details and additional links, this novel mechanism can change its form fromplanar geometries to various hypars. The paper begins with the brief summary of the applications of hypar structures in architecture. Secondly, main principles and deficiencies of the Bennett linkage are presented. According to these deficiencies, structural synthesis of the novel mechanism is considered. Finally, advantages and potential uses of the proposed novel mechanism are explained.

Kinematic Design of a Reconfigurable Deployable Canopy

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 assembly 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.

A Novel Transformable Structural Mechanism for Doubly Ruled Hypar Surfaces

A novel structural mechanism (SM) that is capable of transforming itself into various hyperbolic paraboloid (hypar) geometries is introduced in this paper. Composed of straight bars and novel joint types, the SM is designed based on the ruled surface generation method. Thus, the paper first investigates the geometrical properties and morphology of the hypar surface. Second, it constructs the SM and discusses its transformation capability with respect to its kinematic properties. Then, it presents a parametric model not only to analyze the geometry and possible configurations of the SM but also to prepare a model for the structural analysis. Finally, a transformable shelter structure is proposed as an architectural application of the SM and its feasibility is tested based on the structural analysis conducted in different configurations of the structure. According to the results of the structural analysis, the strength, and the stiffness of the structure are discussed in detail.

Evaluation of structural irregularities based on architectural design considerations in Turkey

Purpose – The purpose of this research is to show significant points which can be used in the architectural design process by investigating the basic principles of earthquake resistant design (ERD) in a deductive format and to contribute to the architectural perception in ERD.Design/methodology/approach – First, the structural irregularity types are examined depending on the rules defined in the Turkish Earthquake Code, 2007 (TEC). Then, architectural design failures related to earthquake resistance of buildings under earthquake loading are visualized and solution suggestions in literature are described in detail by supported drawings.Findings – The problems causing structural irregularities are investigated deeply with given solutions in literature. It is obtained that the significant factors affecting the earthquake performance of structures are: architectural form, structural configuration, slenderness ratio, the location and rate of floor openings, projection rates and symmetry, rigidity and strength ...

A Novel Planar Scissor Structure Transforming Between Concave And Convex Configurations

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.

A new approach to the generation of retractable plate structures based on one-uniform tessellations

Retractable plate structure (RPS) is a family of structures that is a set of cover plates connected by revolute joints. There exists wide range of possibilities related with these structures in architecture. Configuring the suitable shape of rigid plates that are able to be enclosed without any gaps or overlaps in both closed and open configurations and eliminating the possibility of contact between the plates during the deployment have been the most important issues in RPS design process. Many researchers have tried to find the most suitable shape by using kinematical or empirical analysis so far. This study presents a novel approach to find the suitable shape of the plates and their assembly order without any kinematical or empirical analysis. This approach is benefited from the one-uniform mathematical tessellation technique that gives the possibilities of tiling a plate using regular polygons without any gaps or overlaps. In the light of this technique, the shape of the plates is determined as regular polygons and two conditions are introduced to form RPS in which regular polygonal plates are connected by only revolute joints. It should be noted that these plates are not allowed to become overlapped during deployment and form gaps in closed configuration. Additionally, this study aims to reach a single degreeof-freedom (DoF) RPS. It presents a systematic method to convert multi-DoF RPS into single DoF RPS by using the similarity between graph theory and the duality of tessellation. [DOI: 10.1115/1.4036570]

Synthesis of scalable planar scissor linkages with anti-parallelogram loops

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.