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Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG [Abstract] Deployable bar structures are especially useful for emergency buildings. These structures require simplicity and ease of assembly and their performance can be improve by using reciprocal linkage at their bars ends. This reciprocal configuration determines singular constructive conditions that allow all types of cylindrical vaults. This article develops this new system, from a previously theoretical analysis to a test campaign that allows verifying the validity of the proposal. Comparing these results with those resulting from construction systems with straight scissor-like elements or imposed curvature, shows the adequacy of this new proposal, verifying the advantages of the reciprocal joints in cylindrical vaults configurations. This study is part of the research project “Deployable and modular constructions for situations of humanitarian catastrophe”, funded by the Ministry of Economy and Competitiveness of the Kingdom of Spain with reference BIA2016-79459-R. Funding for open access charge: Universidade da Coruña/CISUG

Origami‐based designs refer to the application of the ancient art of origami to solve engineering problems of different nature. Despite being implemented at dimensions that range from the nano to the meter scale, origami‐based designs are always defined by the laws that govern their geometrical properties at any scale. It is thus not surprising to notice that the study of their applications has become of cross‐disciplinary interest. This article aims to review recent origami‐based applications in engineering, design methods and tools, with a focus on research outcomes from 2015 to 2020. First, an introduction to origami history, mathematical background and terminology is given. Origami‐based applications in engineering are reviewed largely in the following fields: biomedical engineering, architecture, robotics, space structures, biomimetic engineering, fold‐cores, and metamaterials. Second, design methods, design tools, and related manufacturing constraints are discussed. Finally, the article concludes with open questions and future challenges.

The future of spaceborne observations is strongly oriented toward miniaturization of payloads without reducing their performances. In this framework telescopes equipped with deployable structures would guarantee either an improvement of the performances or a considerable volume reduction which, due to the limitations on the launcher, translates into a lower cost of in-orbit commissioning. This paper aims at comparing possible mechanism layouts for a deployable space telescope designed for Earth observation in the infrared spectrum. The design considers a classical Cassegrain telescope and aims at packaging the secondary mirror as close as possible to the primary; the trade-off analyses among different technological solutions and configurations are presented. This is a preliminary study performed in the framework of DORA (Deployable Optics for Remote sensing Applications), a project aiming at developing a deployable telescope for minisatellites, and concludes with the assessment of the most feasible layouts which are going to be considered in the next phases of the project.

Composite ultra-thin boom can be folded elastically. Moreover, such booms are able to self-deploy by releasing stored strain energy, which can be applied in deployable antenna, solar sail, and optical telescopes. Surrogate models for imperfection-sensitive quantities of interest and multi-objective optimization are developed for the design of a new N-shape cross-section composite ultra-thin deployable boom. The proposed optimal design method integrates four general steps: (1) design of experiments, wherein the sampling designs of the N boom are created on the basis of the two-factor five-level full factorial design of experiments method; (2) efficient computational analyses of each design sample, wherein the post-buckling behavior of the N boom are analyzed under three different axial directions using nonlinear finite element ABAQUS/Explicit solver; (3) establishing the surrogate models of bending stiffness around the x-and yaxes and torsional stiffness around the z-axis by response surface method (RSM); (4) performing the multi-objective optimization design using modified non-dominated sorting genetic algorithm to realize the optimal design. The bending stiffness around the x-and yaxes and the torsional stiffness around the z-axis are set as the objectives, mass is set as the constraint, and the bonded web height and the central angle of the middle tape spring of the N boom are set as the variables. The typical surrogate modeling method can be applied to different problems in structural and material design.

The 3D deployable frames studied in this work are structures composed of elastic beam elements connected by complex joints. During transformation a controlled snap-through allows the instantaneous stabilization of the structure in an open and in a closed, compact configuration. The mechanics of the transformation is highly nonlinear, since it relies on finite rotations of the structural elements. It is also strongly influenced by geometrical features required for a manufacturing-ready design, such as the finite size of structural elements and sufficient spacing between the beams. These features are generally disregarded in the usual wireframe-based design, but they are taken into account in this work by applying a tailor-made corotational 3D joint finite element, developed to incorporate naturally finite joint size, finite nonlinear joint stiffness and friction effects. The formulation of the proposed joint FE is presented and the performance of the numerical implementation is verified using computational benchmarks. The joint FE is then applied to the numerical investigation of the transformation response of bistable deployable structures from a single module case to large, complex structures. Among other findings, it is shown that the incorporation of finite joint size and beam spacing in the numerical model leads to a different snap-through mechanism that significantly reduces the peak force required for transformation, which could be a basis for future design strategies. Additionally the performance of structures applying the bistable structural pattern on the whole structure or following an entirely modular design (interconnected single modules) is also compared, as a function of the structural size., info:eu-repo/semantics/published

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG [Abstract] Deployable structures are an ideal solution for emergency buildings because of their lightness and compactness, allowing them to be transported to wherever they are needed. Generally the most frequent solutions use Scissor-like-Elements (SLE), but in this case the use of bundle modules is proposed. These systems were developed by Pérez Piñero, but have hardly been used since then. The article analyses the problems they present, as well as their advantages in reducing the number of bars and linkages required, which allows for the design of simpler and more economical structures. The geometrical and mechanical conditions of the linkages for triangular and square modules are analysed, as well as the typologies that may arise. A calculation method is also developed to analyse this type of structure. Finally, the performance of a flat grid is analysed in an analytical and experimental way using reciprocal links at its ends. Both theoretical calculations and experimental tests allow us to demonstrate the viability and efficiency of this new type of structure. This study is part of the research project “Deployable and modular constructions for situations of humanitarian catastrophe”, funded by the Ministry of Economy and Competitiveness of the Kingdom of Spain with reference BIA2016-79459-R

Gossamer structures for innovative space applications, such as solar sails, require technology that allows their controlled and thereby safe deployment. Before employing such technology for a dedicated science mission, it is desirable, if not necessary, to demonstrate its reliability with a Technology Readiness Level (TRL) of six or higher. The aim of the work presented here is to provide reliable technology that enables the controlled deployment and verification of its functionality with various laboratory tests, thereby qualifying the hardware for a first demonstration in low Earth orbit (LEO). The development was made in the Gossamer-1 project of the German Aerospace Center (DLR). This paper provides an overview of the Gossamer-1 mission and hardware development. The system is designed based on the requirements of a technology demonstration mission. The design rests on a crossed boom configuration with triangular sail segments. Employing engineering models, all aspects of the deployment were tested under ambient environment. Several components were also subjected to environmental qualification testing. An innovative stowing and deployment strategy for a controlled deployment, as well as the designs of the bus system, mechanisms and electronics are described. The tests conducted provide insights into the deployment process and allow a mechanical characterization of that deployment process, in particular the measurement of the deployment forces. Deployment on system level could be successfully demonstrated to be robust and controllable. The deployment technology is on TRL four approaching level five, with a qualification model for environmental testing currently being built.

The attention to rainwater evacuation and to the structure protection against meteorological agents has given rise to a set of proposals of pantograph-based deployable structures on rectangular plant, in which these structures define limes and roof planes of sufficient slope. This work starts on the resolution of the layout of deployable structures with a broken guideline, guaranteeing the correct kinematic functioning through the construction of models. Polygonal guidelines, compound curves and also combinations of curves and straight lines are studied. The stabilization problems of the solution in the deployed state are analyzed, incorporating the textile cover and bracing cables. Finally, a set of proposals with different intrados and extrados surfaces and another group of them in which the deployment directions do not follow the two plan axis, are developed and analysed too., La atención a la evacuación del agua de lluvia y a la protección de la estructura ante los agentes meteorológicos ha dado lugar a un conjunto de propuestas de estructuras desplegables de aspas sobre planta rectangular en las que estas estructuras definen limas y faldones de pendiente suficiente. El trabajo parte de la resolución del trazado de estructuras desplegables de aspas planas simétricas y base cuadrangular con directriz quebrada, garantizándose el correcto funcionamiento cinemático mediante la construcción de modelos. Se estudian desplegables con directrices poligonales, curvas compuestas y también combinaciones de curvas y rectas. Se repasan los problemas de estabilización de la solución en el estado desplegado, incorporando la cobertura textil y cables de arriostramiento. Finalmente se desarrollan y analizan geométrica y cinemáticamente una serie de propuestas con superficies de intradós y extradós diferentes y otro grupo de ellas en las que los sentidos de despliegue no siguen los ejes del recinto a cubrir.

International audience; Tensegrity systems are a class of reticulated space structures composed of compressed bars maintained in equilibrium by a network of tensioned cables. Their stiffness depends both on elements’ mechanical properties and their internal self-stress state. Taking advantage of their structural properties, we respond to the challenge of accessibility for everybody to the sea with a new concept of modular lightweight and deployable platforms. Variable configurations are developed to fit ecologically into the marine environment thanks to the transparency of double layer tensegrity structures. Moreover, allowing practical assembly and disassembly is considered in the design to respect the coastal law. Through a numerical study, we demonstrate in this paper the capability of this solution under various representative load cases and support conditions.After the structural and design optimization of elements constrained by weight and stiffness, we detail the design of the nodes, which are the key components ensuring geometry and foldability of the structure. Finally, on-site setting and interfacing with ground supports is experimented in marine conditions to proof the feasibility of this concept.

In civil engineering, there is an occasional need to assure an additional support for a structure due to the loss of the load carrying capacity (e.g., as a result of natural disasters or aging) or for a lightweight structure to support temporary objects (e.g., tents, big advertisement banners, temporary antenna masts). In the present study, the authors propose deployable tensegrity columns to be used in such cases. This paper is aimed at answering the question: Which tensegrity column would be the best for the specified application? Four tensegrity columns are analyzed in various deployment configurations to find the answer to this question. Computer simulations are performed in the finite element (FE) and multibody dynamics (MBD) software to provide quantitative and qualitative results. The applied methods are validated by comparing self-stress states at various steps of the analysis. The most important part of the article is the comparative table, which contains quantitative results obtained from the performed analyses, which can be used to indicate the structures that are most appropriate for certain applications. The results may also be used as a starting point for research in other fields of science like robotics or mechatronics. This paper is focused on obtaining full data for building scaled models for laboratory tests in the future.

This paper produces a design for a minimal mass, deployable support structure for a solar panel covering of water canals. The results are based upon the minimal mass properties of tensegrity structures. The efficient structure is a tensegrity system which has an optimal complexity (i.e. an optimal number of members) for minimal mass. This optimal complexity is derived in this paper, along with deployable schemes which are useful for construction, repairs, for Sun following, and for servicing. It is shown that the minimal structure naturally has deployable features so that extra mass is not needed to add the multifunctional features. The design of bridge structures with tensegrity architecture will show an optimal complexity depending only on material choices and external loads. The minimization problem considers a distributed load (from weight of solar panels and wind loads), subject to buckling and yielding constraints. The result is shown to be a Class 1 Tensegrity substructure (support structure only below the deck). These structures, composed of axially-loaded members (tension and compressive elements), can be easily deployable and have many port-able applications for small spans. The focus of this paper is an application of these minimal mass tensegrity concepts to design shading devices to prevent or reduce evaporation loss, while generating electric power with solar panels as the cover. While the economics of the proposed designs are far from finalized, this paper shows a technical solution that uses the smallest material resources, and shows the technical feasibility of the concept.

A research line in architecture and interior design has been focused for years on the selection of materials with properties specifically tailored for light, thermal and acoustic comforts. An adaptive origami-based structure is here proposed in order to overcome the limited capability of a single material to adjust its response to environmental changes. Such structure is highly flexible, with applications ranging from indoor to outdoor environments. We focus on building facades, to show some results relevant to a small-scale prototype aimed to provide shading to the sunlight.

This study describes the main regularities for the construction of deployable metal shells of a cylindrical type. The comparative analysis of the efficiency of compact folding methods of thin metal shells of cylindrical and conical types, capable of maintaining the initial load-carrying capacity after unfolding without applying the additional strengthening methods, is presented. The range of possible parameters of long-length structures, constructed on the basis of rigid deployable pressurized shells, is characterized. The paper gives the qualitative and quantitative evaluation of basic functional characteristics of folding inflatable metal structures of cylindrical and conical types under the action of a complex of characteristic external loads, close to the maximum allowable ones. The result of experimental operability confirmation of the proposed structures' configurations is presented.

This paper discusses what has been found and what will be found using conceptual “origami” models to develop deployable space structures. The study covers the following: (i) one-dimensional structural elements, which are axially buckled inflatable tubes; (ii) two-dimensional elements, which are deployable membranes, such as solar arrays and solar sails; and (iii) deployable elements in nature. The study clarifies what design considerations are necessary to adapt the basic concepts to actual space structural hardware, and several limitations of origami models are discussed. Regarding the last subject, this study envisions future space structures using conceptual origami models that imitate three-dimensional deployable structures in nature, such as flowers and insect wings.

Most deployable structures, such as operable roofs and masts, move over one degree of freedom. This paper describes a structure that involves loosely coupled movement over several degrees of freedom. Analysis models of these structures are typically inaccurate. A source of inaccuracy is joint friction. Static and kinetic friction are studied experimentally and analytically. Simulations have been modified to account for these effects, and two methods are used to quantify friction effects. Friction has a significant effect on the movement of the tensegrity structure. Of two candidate parameters, cable tension and interior cable angle, cable angle is the factor that best characterizes friction effects. Values of static and kinetic friction coefficients are not significantly different in this context, and this leads to a reduction in the complexity of the friction model for simulation. Including friction effects in analysis decreases the difference between simulations and tests. Lastly, strut elements of the tensegrity structure are most critically affected by friction. (C) 2017 American Society of Civil Engineers.

International audience; This study focuses on deployable systems actuated by shape memory alloys in the perspective of designing adaptive sun shading devices for building facades. We first set the context of smart materials for adaptive facades and underline the remarkable characteristics of shape memory alloys for mechanical ac-tuation purposes. After outlining the constraints on the integration of this material into deployable structures, we introduce three different prototypes actuated by shape memory alloy wires. They have been fabricated and tests have been carried out on two of them. Finally, we present some perspectives on the use of these actuators for solar shading systems in façade engineering.

Accepted: 2013-07-23, 資料番号: SA1004508000

A closed-loop overconstrained spatial mechanism composed of six hinge-jointed bars, which has three planes of symmetry in any position, is called a threefold-symmetric Bricard linkage. In this paper a kinematic analysis of these linkages is presented. It is pointed out that for particular parameter values, kinematic bifurcation of the linkages can occur. Features of the kinematic bifurcation are discussed in detail. The applicability of threefold-symmetric Bricard linkages and of their alternative forms to deployable structures is investigated. In addition, by using the theory of kinematic bifurcation, a snap-through phenomenon appearing in a deployable hexagonal ring is explained. © 2004 Elsevier Ltd. All rights reserved.

Tensegrity structures are spatial systems composed of tension and compression components in a self-equilibrated prestress stable state. Although the concept is over 60 years old, few tensegrity-based structures have been used for engineering purposes. Tensegrity-ring modules are deployable modules composed of a single strut circuit that, when combined, create a hollow rope. The "hollow-rope" concept was shown to be a viable system for a tensegrity footbridge. This paper focuses on the deployment of pentagonal ring modules for a deployable footbridge application. The deployment sequence of a module is controlled by adjusting cable lengths (cable actuation). The geometric study of the deployment for a single module identified the path space allowing deployment without strut contact. Additionally, a deployment path that reduces the number of actuated cables was found. The number of actuated cables is further reduced by employing continuous cables. A first-generation prototype was used to verify both findings experimentally. The structural response during both unfolding and folding is studied numerically using the dynamic relaxation method. The deployment-analysis algorithm applies cable-length changes first to create finite mechanisms allowing deployment and then to find new equilibrium configurations. Therefore, the actuation-step size is identified as the most critical parameter for a successful deployment analysis. Finally, it is shown that the deployability of the footbridge does not affect its element sizing because stresses during deployment are lower than in-service values. DOI:10.1061/(ASCE)ST.1943-541X.0000491. (C) 2012 American Society of Civil Engineers.

Tensegrities are spatial, reticulated and lightweight structures that are increasingly investigated as structural solutions for active and deployable structures. Tensegrity systems are composed only of axially loaded elements and this provides opportunities for actuation and deployment through changing element lengths. In cable-based actuation strategies, the deficiency of having to control too many cable elements can be overcome by connecting several cables. However, clustering active cables significantly changes the mechanics of classical tensegrity structures. Challenges emerge for structural analysis, control and actuation. In this paper, a modified dynamic relaxation (DR) algorithm is presented for static analysis and form-finding. The method is extended to accommodate clustered tensegrity structures. The applicability of the modified DR to this type of structure is demonstrated. Furthermore, the performance of the proposed method is compared with that of a transient stiffness method. Results obtained from two numerical examples show that the values predicted by the DR method are in a good agreement with those generated by the transient stiffness method. Finally it is shown that the DR method scales up to larger structures more efficiently. (C) 2010 Elsevier Ltd. All rights reserved.

A concept for a mobile shelter is proposed, based on the geometry and kinematic behaviour of foldable plate structures. The folding pattern and the associated design parameters are discussed, along with their influence on the geometry and the kinematic behaviour. It is shown that the transition can be made from a foldable plate structure to a foldable bar structure, while retaining an identical kinematic behaviour. This is done by introducing custom-built joints for connecting the bars which allow the system to deploy in the desired way, maintaining the same D.O.F (degree of freedom) as the plate system. For the structure to be employable as a fully-fledged temporary space enclosure, a lightweight textile membrane is incorporated beforehand and deployed along with the bar structure.

In this work we investigated the stability behavior and the folding capability of an ultrathin tubular composite boom with C-cross section to be used in nanosatellites applications. A nonlinear buckling analysis was performed using the Riks method, adopting a perturbed finite element model to study the influence of the unavoidable geometrical variations of the boom thickness, arising from the composite manufacturing processes, on the stability behavior of the tubular structure. The effect of several levels of geometrical imperfection on the buckling behavior was analyzed. The minimum coil radius that can be used for a safe storage the boom was determined by quasi-static explicit analysis. The boom folding process was considered as formed by two sequential steps, the flattening and the coiling. The stress fields associated with both steps were investigated.

Transformable structures facilitate reuse of components and structures by increasing the speed and ease of erection and lowering the stacking volume during transportation. Thanks to its unique ability to use structural members under different curvatures and return bent elements to their initial straight or planar geometry, active bending has the potential to expand the existing morphology of transformable structures. This paper discusses the development of such structural and kinematical systems on a theoretical level. First we will give a review of the existing systems for transformable and active-bending structures. By combining these, we have developed new kinematical systems of which three were selected for the scope of this paper: deployable grids, active bending kit-of- parts systems and pliable textile hybrids. These will be discussed in more detail and applied on a first design case, illustrating the potential applicability in a real case. The kinematical study shows the potential of active bending intransformable structures. Using elastic deformations lowers the complexity of the structures and can be actively used in the structural transformation. However, questions about the structural behaviour and technical detailing remain for future research.

The aim of the GOSSAMER-1 mission is an in-orbit deployment of versatile ultra-lightweight deployable sail hardware as a feasibility demonstration. The presented work focuses on the design and manufacturing of the sail membrane for GOSSAMER-1. The work has reached a preliminary design status which shall be presented in this paper. It includes mechanical analysis as well as a description of manufacturing strategies at the department of System Conditioning at the DLR Institute of Space Systems in Bremen.

In the search for producing a low ecological footprint, a lightweight and high-performing technology, bending-active approach has been proposed to be appropriate for kinetic and transformable structures. While traditional deployable structures base their transformability on their hinges topology, pliable structures are based on the elastic deformation of elements. This paper will focus on the feasibility and serviceability of timber pliable bending-active structures by presenting two systems based on rigid couplings of coplanar flat planks. We discuss then their potential in simplifying manufacturing and assembling processes of kinetic systems by the enhancement of the elastic properties of the material, and efficient yet simple fabrication. This paper will present a topological classification of a variety of pliable structures based on rigid couplings. Furthermore it will discuss the implementation in architectural scale of one of the derived systems in a deployable fast-erected pavilion.

Thin-walled composite deployable structures are an attractive solution for many aerospace missions, especially when large configurations are required. This paper investigates the feasibility of coiling an ultra-thin composite boom into a small deployment system. Detailed simulation of the coiling process of a C-section boom made from a two-ply laminate of carbon fiber reinforced plastic was performed using non-linear explicit dynamic analysis. A complete description of the analysis parameters that control the numerical stability of the simulation, and of the boundary conditions and loads adopted to perform the folding process are reported within this paper. The simulation is divided into two consecutive stages: the flattening of the boom, and the coiling inside the deployment device. The accuracy of the results is verified using energy balance assessments, and the structural strength of the boom is evaluated via three specific failure criteria. A parametric analysis of geometrical parameters was carried out in order to find out the slot configuration allowing the boom to fold without reaching its failure.

Recently, responsive building skins have gained importance in the world of architectural engineering. A lot of research has been done on control systems required to obtain responsive façades, but the real challenge today is the development of a new generation of components and structures which are able to give the building envelope the required transformability. The scope of this paper is to analyse to what extent deployable scissor structures are appropriate for use in a responsive building skin. The parameters analysed in this research are the type of transformation, the type of deployment and the morphology. Of course, a lot of other aspects have an influence on the applicability of scissors structures in the building envelope, but these fall out of the scope of this paper. The result of the analysis is a first impression on the behaviour of scissor structures in the building envelope and possible applications, based on their shape and transformation characteristics. This paper can be considered as a starting point for further development of deployable scissor structures for responsive building skins.

This paper explores the possibilities of transformable structures in architectural and structural engineering. Key aspects concerning the design, analysis and construction of mobile, as well as adaptable constructions, are explained. The transformation of such structures, intended to meet changing require¬ments, is done by using mechanisms (deployable/foldable) or reconfig¬urable components (demountable kit-of-parts). Transformable structures can adapt their shape or function according to changing circumstances (Fig. 1 & 2), to meet rapidly evolving needs, induced by a society which - progressively - embraces the concept of sustainable design. This is further supported by the understanding that structures are not designed in an end state, but in a transition state, hence 'transformable structures'. Based on how this transformation is realised, two groups of structures can be distinguished. The transformation of the structure is primarily done by either: (i) incorporating a kinematic mechanism, enabling the structure to deploy from a compact configuration (e.g. for transport) to a larger, expanded state in which it can fulfil its architectural function (e.g. providing shelter) or, (ii) by designing and realising the structure as a kit-of-parts system (cfr. Meccano construction toy) with dry, reversible connections between the constitutive components, enabling design for disassembly, whereby all components can be reconfigured, replaced or re-used. The former systems are primarily aimed at the field of temporary construction, in which lightweight, deployable structures are of great use, while the latter are primarily aimed at allowing a structure to be adapted gradually over time. The paper explores the possibilities and limits of both systems, including topics such as geometric design, kinematic behaviour, structural analysis, design- and analysis software and sustainable design. Conclusions are drawn on the current state-of-the-art and suggestions are made for future research. This paper servesas an introduction to the other papers participating in the special session on 'Transformable Structures' at the HPSM 2012 Conference.

Non-static structures that can adapt their shape, or which can be quickly and easily deployed to perform their architectural function and removed afterwards without damaging sensitive sites, are well-equipped to meet the demands of a rapidly changing society which embraces the concept of sustainable design. Generally, mobile deployable structures are capable of transforming from a small, closed or stowed configuration to a much larger, open or deployed configuration. In architecture, the main applications are temporary lightweight structures such as emergency shelters or exhibition and recreational structures. For these purposes deployable scissor structures are most effective. They consist of beam elements connected by pivot joints, allowing them to be folded into a compact bundle for storage or transport. Subsequently, they are deployed, demonstrating a huge volume expansion. This process can be reversed, allowing reuse. In this paper an innovative kit-of-parts system is developed for deployable scissor structures. A new multi-configurational Universal Scissor Component (USC) is geometrically designed to create scissor structures in a generic way. The designed USC – single and unique – is used to compose different configurations. The structures can be disassembled and the USC can then be reconfigured, enabling reuse (cfr. the toy construction system Meccano). The component’s uniformity favours mass-production, implying a cost benefit. Moreover, the diversity in possible structural forms invites multiple uses.

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. (C) 2010 Elsevier Ltd. All rights reserved.

Reciprocal Frames are an interesting but almost unknown class of structures, based on the assemblage of straight one dimensional elements into spatial structures. They differ from truss structures because elements are joined by contact at intermediate and end points, and they can reach stability without the need of pins. RF aroused lively interest in scientists since antiquity, as the studies of Leonardo da Vinci, Villers de Honnecourt and Sebastiano Serlio confirm, and the interest has increased recently as an effect of the realizations of many timber reciprocal structures all around the world. The research illustrated in the paper concerns the study of the mechanical behavior of such structures, starting from the kinematic and static determinacy of plane configurations, with the aim to understand the basic properties of these structures. In spite of their apparent simplicity, the mechanics of RF is very complex, involving contact and friction problems, and frequently the geometry itself of two dimensional RF leads to complex analyses. The concept of reciprocity, in fact, make the position of each element determinate by the position of all the other ones, so that large configurations cannot be obtained simply adding new elements to smaller configurations. While recent applications in architecture seem to emphasize the simplicity and the naiveness of this kind of construction, trough timber construction, for instance, or for buildings with a specific social role, as museums or small theaters, we are firmly convinced that RF can be of interest when approached in more technological way. Our research is then specifically oriented to Deployable RE, in which a high tech construction can improve consistently the performances, allowing the design of innovative structures. An promising application of DRF are historical buildings and archeological sites, when the level of damage makes hard to recover the original functionality, so that reversible and non-invasive intervention are required

The opportunities of fully foldable structures are well utilized in some industries, but are only rarely applied in the built environment. In the first part of this study, a number of folding typologies are investigated and their (un)favourable properties are related to the built environment. In the second part, the results of the first part are exploited in order to design an adaptable pavilion. The conclusion of the first part of the study is that there are multiple folding typologies which can generate a wide variety of forms. However, there is especially one typology with a high potential to translate the folding patterns into real structures. This folding typology is called non-singular, rigid foldable. The advantage of this typology is that the individual surfaces do not bend during the folding motion, while the degrees of freedom (DOF) are only dependent on geometric characteristics of the folding patterns. The second part of the study uses the results from the first part in order to design an adaptable pavilion. To design this pavilion a variant study is performed with folding patterns which belong to the stable adaptive typology. The variants are compared to each other with respect to their: structural performance, innovative appearance, effective floor space range and ease of transportation as well as deployability. From this study the final variant is studied in more detail and a structural analysis is performed based on the Eurocode for temporary structures. In this non-linear structural analysis, the structure is modelled in various configurations. The resulting design leads to an innovative pavilion which is able to transform in multiple configurations by only moving the support points, while it is stable for every possible state., The opportunities of fully foldable structures are well utilized in some industries, but are only rarely applied in the built environment. In the first part of this study, a number of folding typologies are investigated and their (un)favourable properties are related to the built environment. In the second part, the results of the first part are exploited in order to design an adaptable pavilion.The conclusion of the first part of the study is that there are multiple folding typologies which can generate a wide variety of forms. However, there is especially one typology with a high potential to translate the folding patterns into real structures. This folding typology is called non-singular, rigid foldable. The advantage of this typology is that the individual surfaces do not bend during the folding motion, while the degrees of freedom (DOF) are only dependent on geometric characteristics of the folding patterns.The second part of the study uses the results from the first part in order to design an adaptable pavilion. To design this pavilion a variant study is performed with folding patterns which belong to the stable adaptive typology. The variants are compared to each other with respect to their: structural performance, innovative appearance, effective floor space range and ease of transportation as well as deployability.From this study the final variant is studied in more detail and a structural analysis is performed based on the Eurocode for temporary structures. In this non-linear structural analysis, the structure is modelled in various configurations. The resulting design leads to an innovative pavilion which is able to transform in multiple configurations by only moving the support points, while it is stable for every possible state

By rapidly expanding from a compact, stowed bundle to a functional space enclosure, deployable structures can address temporary needs in a minimum amount of time. Using the intrinsic elastic behaviour of flexible elements — active bending — in the design of transformable or deployable structures leads to a wide range of kinetic concepts. This component transformation can decrease the complexity that often comes with rigid-body mechanisms. This paper presents one principle for deployable bending-active structures, based on the interaction between a deployable grid and a restraining membrane: deployable textile hybrid structures. A case study illustrates the design concept and the deployment and assembly processes that allow multiple structural transformations. The large interdependency of the form and material behaviour of bending-active structures, contrary to conventional form-active structures, requires a specific modelling approach. The approach presented in this paper allows feedback between the parametric input of starting geometry and material characteristics, and the output geometry and internal stress. Working with a high-strain fabric without cutting pattern, balancing the stresses and strains between the bending elements and tensile fabric becomes the prime focus. Although the preliminary results are acceptable in theory, a more detailed structural analysis and real-scale models should validate the assumptions of rapid assembly and the structural behaviour on a realistic and practical level.

Deployable structures belong to a special class of moveable structures that are capable of form and size change. Controlling movement of deployable structures is important for successful deployment, in-service adaptation and safety. In this paper, measurements and control methodologies contribute to the development of an efficient learning strategy and a damage-compensation algorithm for a deployable tensegrity structure. The general motivation of this work is to develop an efficient bio-inspired control framework through real-time measurement, adaptation, and learning. Building on previous work, an enhanced deployment algorithm involves re-use of control commands in order to reduce computation time for mid-span connection. Simulations are integrated into a stochastic search algorithm and combined with case-reuse as well as real-time measurements. Although data collection requires instrumentation, this methodology performs significantly better than without real-time measurements. This paper presents the procedure and generally applicable methodologies to improve deployment paths, to control the shape of a structure through optimization, and to control the structure to adapt after a damage event.

Curved-line folding is the act of folding paper along a curved crease pattern in order to create a 3D shape, using the combination of folding (plastic deformation) and bending (elastic deformation). Up until now, the use of curved- line folding in architecture has been limited to static applications only, such as metal sculptures or façade panels. However, the elastic deformations that occur when a flat sheet is forced into a curved shape can produce an interesting transformation process. The elastic deformation of one area of the sheet results in the folding and bending of adjacent surface areas as the internal forces and moments are transferred through the curved creases. This paper explains how this behaviour can be used for the design of deployable structures finding their application in the context of adaptive shading. Through the analysis of various crease patterns and the fabrication of small scale models, some important design parameters are defined. This paper demonstrates how the choice of the composition of the crease pattern, the curvature of the creases and the Length-Thickness Ratio affect the resulting kinetic system. The outcome of the analysis is useful for the design of deployable structures based on curved-line folding.

Disaster relief shelters must be transitional, meaning capable of serving an affected community from emergency, to rehabilitation, to reconstruction. Deployable scissor structures are well-suited for this application since they are lightweight, can be compactly packaged, and have a high volume expansion ratio. Their constitutive parts can be reused and reconfigured to facilitate rehabilitation and reconstruction. This paper presents a preliminary concept for a deployable scissor shelter, including its design, analysis, and experimental validation on a full-scale prototype. First, the conceptual design and analysis using a parametric finite element method are presented. Testing of the prototype is then employed to evaluate the deployment process, support conditions and stiffening elements. Experimental data from these studies validates results from the finite element model, suggesting that the modeling tool is effective for the design of transitional shelters. A final design is presented which meets the requirements of the European Standards.

Deployable scissor structures can transform from a compact bundle of elements to a fully expanded configuration. Due to this transformational capacity there is a mutual relation between the geometry, the kinematics and the structural response of the scissor system, resulting in a relatively complex design process. In order to understand how geometrical parameters influence the structural performance, it is beneficial to evaluate these structures at a pre-design stage. To reach this goal, we developed an integrated framework for pre-design evaluation using the parametric finite element tool Karamba in combination with Matlab. By doing so an automatic and immediate preliminary structural evaluation can be established that guides the designer in making efficient geometrical design decisions. This paper evaluates design parameters for deployable scissor arches using this framework. More specifically, the influence of the most important geometrical inputs - scissor type, number of scissor units, structural thickness and height of the arch - on structural performance (i.e. stress, deflection and mass) is determined. Results indicate the sensitivity of the considered parameters and their importance in the design of scissor arches. With this knowledge in an early design stage, the subsequent design optimisation, detailed analysis and realisation are enhanced. © 2014 WIT Press.

In architectural engineering, deployable scissor structures are generally used for mobile and temporary applications. They are characterised by their dual functionality as either kinematic mechanisms (during deployment) or loadbearing skeletal structures (after deployment). It is crucial to realise that there is a direct and mutual relationship between the geometry, the kinematics and the structural response of the scissor system. Due to a relatively complex design process it can be highly beneficial to evaluate these structures at a pre-design stage in terms of their structural performance. In order to do so, new computational methods are introduced. Karamba is a finite element plug-in for Grasshopper, fully embedded in the 3D modelling software Rhinoceros, which calculates interactively the response of three dimensional beam structures. The advantage of this new tool is the compatibility with the parametric environment of Grasshopper. These software tools are still in development, but already show their potential in terms of geometric modelling and structural optimisation. In this research it is shown in which way these evolving computational methods can contribute to the design of deployable scissor structures. By using the proposed methodology of preliminary evaluation, the scissor structures are geometrically and structurally optimised at an early stage, thereby enhancing the overall design process and facilitating further detailed analysis.

The paper describes the results of the deployment testing of the De-Orbit Sail flight hardware, a drag sail for de-orbiting applications, performed by DLR. It addresses in particular the deployment tests of the fullscale sail subsystem and deployment force tests performed on the boom deployment module. For the fullscale sail testing a gravity compensation device is used which is described in detail. It allows observations of the in-plane interaction of the booms with the sail membrane and the central satellite body to which the booms and sails are attached. During the tests issues with the sail deployment tests were encountered which lead to design changes regarding the sail and type of sail attachment.