New concepts in deployable beam structures

The design of deployable structures involves a complicated tradeoff of packaging efficiency, the overall mechanism associated with deploying and latching beam joints, and the requirements and complexity of the beam deployer/repacker. Three longeron deployable beams, controllable geometry beams, and hybrid deployable/erectable beam concepts are evaluated

On the incompressibility of cylindrical origami patterns

The art and science of folding intricate three-dimensional structures out of paper has occupied artists, designers, engineers, and mathematicians for decades, culminating in the design of deployable structures and mechanical metamaterials. Here we investigate the axial compressibility of origami cylinders, i.e., cylindrical structures folded from rectangular sheets of paper. We prove, using geometric arguments, that a general fold pattern only allows for a finite number of \emph{isometric} cylindrical embeddings. Therefore, compressibility of such structures requires either stretching the material or deforming the folds. Our result considerably restricts the space of constructions that must be searched when designing new types of origami-based rigid-foldable deployable structures and metamaterials

Structural/thermal considerations for design of large space platform structures

A method is described for placing a large, STS-compatible platform on orbit utilizing a construction method employing both deployable and erectable structures. A multifunctional mechanism is used for deployable structures and an on-orbit assembly is used for erectable structures. Also analyses are discussed which assess the thermal distortion of a simple open truss and a more complex truss

Deployable Arches Based on Regular Polygon Geometry

This paper discusses a deployable-arch-structure design that is built using articulated bars, commonly called a scissor-system, and is based on the regular polygon geometry. The deployed-arch shape can be determined by inscribing regular polygon geometry in a circle. It is defined by the: a. number of bars required, b. position of the pivots, c. pivot-point distances, d. bar length, and e. open-geometry angle of the arches. The goal is a deployable half dome made up of semi-arches. Traditional arch construction depends on external structures to provide stability until the keystone is set, which then allows the supports to removed. Deployable structures avoid the need for these external supports greatly simplifying the assembly process and deployment time.Postprint (published version

Deployable structures in the built environment

The occurrence of natural disasters has been on the increase for the last decade. One of the most prominent incidences has been the occurrence of floods which has been experienced in developing and developed countries. This has been the experience of Turkey and the United Kingdom. The world has also experienced hurricanes and earthquakes in the recent times. Global temperature change has been blamed for many of these natural disaster occurrences. Man-made disaster incidences have also been recorded such as wars, chemical plant explosions, building failure/collapse and have been on the increase. The consequences of these occurrences have resulted in the loss of lives and properties, displaced communities/stranded communities and also economic stagnation. It is therefore imperative that there should be structures or ways to mitigate the loss of general infrastructures especially housing. These structures should be readily available and meet the temporary needs of the community. Deployable structures are known to be light-weight in nature and characteristic reduced time frame to deploy in its predetermined configuration

Joint for deployable structures

A joint is described for connecting a pair of beams to pivot them between positions in alignment or beside one another, which is of light weight and which operates in a controlled manner. The joint includes a pair of fittings and at least one center link having opposite ends pivotally connected to opposite fittings and having axes that pass through centerplates of the fittings. A control link having opposite ends pivotally connected to the different fittings controls their relative orientations, and a toggle assemly holds the fittings in the deployed configuration wherein they are aligned. The fittings have stops that lie on one side of the centerplane opposite the toggle assembly

Recent advances in structural technology for large deployable and erectable spacecraft

Ultra-low mass deployable and erectable truss structure designs for spacecraft are identified using computerized structural sizing techniques. Extremely slender strut proportions are shown to characterize minimum mass spacecraft which are designed for shuttle transport to orbit. Discrete element effects using a recently developed buckling theory for periodic lattice type structures are presented. An analysis of fabrication imperfection effects on the surface accuracy of four different antenna reflector structures is summarized. The tetrahedral truss has the greatest potential of the structures examined for application to accurate or large reflectors. A deployable module which can be efficiently transported is identified and shown to have significant potential for application to future antenna requirements. Investigations of erectable structure assembly are reviewed

Clevis joint for deployable space structures

This invention relates generally to pin clevis joints, and more particularly, to zero play pin clevis joints for connecting structural members of a deployable space structure. A joint includes a pin, a tang, and a shackle. The pin is tapered at the same angle as the bores extending through the projections of the shackle and the tang. A spring washer biases the tang onto the tapered sidewall of the pin. The invention solves the free play problem associated with deployable space structures by using a tapered pin which is held in tapered holes by the spring washers

Design considerations for joints in deployable space truss structures

All of the structures considered for the Control of Flexible Structures (COFS) flight experiments are deployable truss structures and their response will be dominated by the structural response of the joints. To prepare for these experiments some fundamental research work is being conducted in the Structures and Dynamics Division at LaRC which will provide insight into structurally efficient and predictable deployable truss joints. This work involves generic studies of the static and dynamic response of joints as well as the development of analytical models which can be used to predict the response of a large multijointed truss. In addition to the generic joint studies, the research effort encompasses the design and fabrication of a 20-meter long deployable truss beam for laboratory evaluation of its structural characteristics and correlation with developed prediction methods. The experimental results have indicated the importance of attention to detail in the design and fabrication of joints for deployable truss structures. The dimensional relations and material considerations for efficient pin-clevis joints have been outlined. Results of tests on the near-center latch are discussed

Deployable structures classification : a review

Deployable structures have the capacity to transform and predictably adopt multiple predetermined configurations, moving through known paths, while deploying in a controlled and safe way. These characteristics introduce benefits when considering issues such as ease of transportation, erection and the overall sustainability of the structure by means of high material efficiency, modularisation and maximum use of natural energy resources. The aim of this article is to provide a critical review of existing attempts at classifying deployable structures identifying connections between different families through their mechanical and structural behaviours. The classifications selected consider theoretical and applied deployable structures, not focusing on a single application of deployable structures but including those ranging from spatial applications, to temporary and disaster relief structure, through to medical applications, providing coherence where terminology varies between applications. In order to gain a consistent understanding, tree diagrams were created for the review/classification to allow drawing commonalities and establishing differences between authors. A chronological approach was adopted, using key review work as focal points for the timeline, complemented by smaller more specific pieces of work. This enabled the identification of common features and divergences between the different authors, bringing to the conclusion that a clear, comprehensive, consistent and unified classification of deployable structures is currently missing within the field