Thin cylindrical shell structures may provide an interesting breakthrough for deployable structures for small satellites. Its bi-stable behaviour allows two different stable configurations: coiled and deployed. Several projects worldwide are using tape springs for satellites and for the SEAM project, at KTH, 1 meter long tape springs will be used for booms. This thesis investigates the energy stored inside the tape spring according to its layup configuration and the different fiber orientations. With a thickness around 0.3 mm and a length of one meter, the booms will deploy sensors with a quite low deployment speed in order to minimize the shick load during the deployment phase. A Matlab code is written to compare the stored strain energy. Another aim is to find an adequate layout all along the tape spring, it means change the fiber orientation to decrease the energy released, but also generating main manufacturing issue.

The developing world often relies on low-water crossings on unpaved roads in place of bridges for vehicle river crossings and impoverished communities suffer disproportionately more from road shut-downs. This project defines a modular and deployable bridge solution to combat low-water crossing hazards in undeveloped road systems in year-round conditions using Systems Engineering and related methodologies to architect the solution.

The purpose of this research is to develop fundamentals of compliant mechanisms in deployable space systems. The scope was limited to creating methods for thick origami, developing compliant deployable solar arrays, and developing methods for stowing and deploying the arrays. The research on actuation methods was focused on a one-time deployment of the array. Concepts for both passive and active actuation were considered. The primary objective of this work was to develop approaches to accommodate thickness in origami-based deployable arrays with a high ratio of deployed-to-stowed diameter. The HanaFlex design was derived from the origami flasher model and is developed as a deployable solar array for large arrays (150 kW or greater) and CubeSat arrays (60 W). The origami folding concept enables compact stowage of the array, which would be deployed from a hexagonal prism into a flat array with about a 10-times increase in deployed diameter as compared to stowed diameter. The work on the origami pattern for the solar array was also applied to the folding of 80-100 m2 solar sails for two NASA CubeSat missions, NEA-Scout and Lunar Flashlight. The CubeSat program is a promising avenue to put the solar array or solar sails into space for testing and proving their functionality. The deployable array concept is easily scalable, although application to CubeSats changes some of the design constraints. The thickness-to-diameter ratio is larger, making the issues of thickness more pronounced. Methods of actuation are also limited on CubeSats because of the rigorous size and weight constraints. This dissertation also includes the development of a compact, self-deploying array based on a tapered map fold design. The tapered map fold was modified by applying an elastic membrane to one side of the array and adequately spacing the panels adjacent to valley folds. Through this approach, the array can be folded into a fully dense stowed volume. Potential applications for the array include a collapsible solar array for military or backpacking applications. Additional compliant mechanism design was done in support of the HanaFlex array. This included a serpentine flexure to attach the array to the perimeter truss for deployment, and a bistable mechanism that may be used in the deployment of the array or sail.

The ancient art of ‘origami’ has recently become the source of inspiration for engineers to create structures that can unfold from a compact state to a fully deployed one. For instance, researchers have currently adopted origami designs in various engineering disciplines, including aerospace engineering, robotics, biomedical engineering, and architecture. In particular, architects have been interested in designing origami-inspired rigid walled structures that can be deployed as disaster-relief shelters. This type of design has three main advantages: transportability, constructability, and rigidity. Although there has been increased interests in deployable structures, limited research has been conducted on evaluating their structural performance, specifically the mechanical performance of the hinges that allow for the rotation of the rigid panels. To address the limitation, this thesis proposes a novel design of hinge connections for rigid origami structures. The hinges utilize snap fit connections to allow for the structure to achieve and maintain a locked state once unfolded without the need for any additional connections. Prototypes of the hinge design were fabricated using a 3D printer and their flexural strength was experimentally and computationally studied. It was concluded that the design could resist typical flexural loads for residential structures, and future research should be performed to minimize deflection.

This thesis provides resources that enable the design of novel and compact mechanical devices by providing terminology, engineering models, and design methods in the fields of developable mechanisms and origami-based engineering.The first part of this work presents engineering models to aid in the design of cylindrical developable mechanisms. These models take into account the added spatial restrictions imposed by the developable surface. Equations are provided for the kinematic analysis of cylindrical developable mechanisms. A new classification for developable mechanisms is also presented (intramobile, extramobile, and transmobile) and two graphical methods are provided for determining this classification for single-DOF planar cylindrical developable mechanisms. Characteristics specific to four-bar cylindrical developable mechanisms are also discussed. The second part addresses a key challenge in origami design: how to achieve stability while maintaining the desired folding motion. The origami stability integration method (OSIM) provides an approach for graphically combining various techniques to achieve stability. This thesis presents improvements and additions to the OSIM that allow it to be applied to many different scenarios. Existing stability techniques are also categorized into four groups based on whether they are intrinsic or extrinsic to the origami pattern and whether they exhibit gradual or non-gradual energy storage behaviors. These categorizations can help designers select appropriate techniques for their application. Four case studies are presented which use the OSIM and the technique categorization to conceptualize stability in origami-based devices.

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The 2012 Decadal Survey has stated that there is a critical role for a Venus In-situ Explore (VISE) missions to a variety of important sites, specifically the Tessera terrain. This work aims to answer the Decadal Survey's call by developing a new comprehensive Entry, Descent, Landing, and Locomotion (EDLL) vehicle for in-situ exploration of Venus, especially in the Tessera regions. TANDEM, the Tension Adjustable Network for Deploying Entry Membrane, is a new planetary probe concept in which all of EDLL is achieved by a single multifunctional tensegrity structure. The concept uses same fundamental concept as the ADEPT (Adaptable Deployable Entry and Placement Technology) deployable heat shield but replaces the standard internal structure with the structure from the tensegrity-actuated rover to provide a combined aeroshell and rover design. The tensegrity system implemented by TANDEM reduces the mass of the overall system while enabling surface locomotion and mitigating risk associated with landing in the rough terrain of Venus's Tessera regions, which is otherwise nearly inaccessible to surface missions. TANDEM was compared to other state-of-the-art lander designs for an in-situ mission to Venus. It was shown that TANDEM provides the same scientific experimentation capabilities that were proposed for the VITaL mission, with a combined mass reduction for the aeroshell and lander of 52% (1445 kg), while eliminating the identified risks associated with entry loads and very rough terrain. Additionally, TANDEM provides locomotion when on the surface as well as a host of other maneuvers during entry and descent, which was not present in the VITaL design. Based on its unique multifunctional infrastructure and excellent crashworthiness for impact on rough surfaces, TANDEM presents a robust system to address some of the Decadal Survey's most pressing questions about Venus. / Ph. D.

The cyclic trajectory described here exemplifies a loosely defined, continuously evolving set of questions, results, and methodologies that have emerged during the process of design by making. Through a series of prototypical building components and assemblies this collection presents a design process that began with a top-down program-specific design process that informed the development of a unique building system and enabled a bottom up formal exploration. As the design thesis for the first professional Master of Architecture degree, this exploration surrounds the design, fabrication, and deployment of a series of component-based building assemblies. One example, the SEEDS Pavilion At Hawks Ridge, serves as a remote base of operations for a local youth organization that supports field-based environmental education. The pavilion continues an investigation of user assembled construction and is based on a component group that can be assembled on-site by camp children. Each building component was manufactured using on campus fabrication laboratories and was assembled on-site by a group of supervised SEEDS camp student-volunteers during a two-day design-build workshop at the Hawk's Ridge Preserve in Floyd, Virginia. The form of the structure is derived by the limitation of component number, size, and assembly sequence and represents the conflict between a parametrically derived prescriptive shape and the forms that result from the bottom up exploration of the physical system itself. The component-based construction is made possible by a series of nodal linkage assemblies designed to accommodate variations in on-site conditions using a strategic 'sloppy detail' that enables a high degree of assembly and deployment tolerance. The following collection of sequential images outlines construction of several prototypical components and assemblies and is intended to represent a continuance, not an end, to a long-term effort. / Master of Architecture

This research presents methods for modeling and optimizing an origami design using compliant mechanisms, improving origami design processes, modeling and analyzing rolling behavior of compliant designs, and an antenna design for SmallSats. A framework for the optimization of the origami Flasher pattern to mitigate issues with rigid-foldability is shown, and several optimization solutions are presented to overcome these issues. An alternative design method is presented which allows designers to more accurately predict the characteristics of a design in the deployed state, and configurations are shown for an example use case. A model for rolled gossamer structures is presented which predicts the relative slippage that adjacent panels will experience, and slippage trends are correlated with key pattern parameters. Finally, a SmallSat antenna design is presented, which stows compactly, incorporates a unique hinge design, utilizes magnets for stabilization in the deployed state, and self-deploys using compliant mechanisms.

Deployable structures are used for many different spacecraft applications like solar arrays, antennas, and booms. They allow spacecraft with large structural components to comply with the volume restrictions of launch platforms. This research optimizes the shape and size of these structural components with both the stowed and deployed configurations in mind. HEEDS, a commercial optimization software, and ABAQUS, a commercial finite element analysis software, are used to evaluate and alter the structure using a single simulation. This makes the design process more efficient than running many different simulations individually. The optimization objectives, design variables, and constraints are chosen to fit the mission requirements of the structure. The structure analyzed in this research is a composite tube with a compressible cross-section wrapped around a cylinder. The change in cross-section reduces the bending stiffness of the tube and allows it to be wrapped without damaging the material. The dimensions controlling cross-section shape and the thickness of the composite layers are the design variables for the optimization. The maximum strain energy stored in the wrapped tube, the minimum volume of the structure, and the minimum weight of the tube are the objectives for the optimization. The strain energy is maximized to get the stiffest possible structure and satisfy the minimum natural frequency constraint. The weight and volume of the tube are minimized because reducing weight and volume is important for any spacecraft structure. Constraints are placed on the design variables and objectives and the Hashin damage criteria are used to ensure wrapping does not cause material failure. Three optimization runs from different initial designs are completed using SHERPA and genetic algorithm optimization methods. The results are compared to determine which optimization method performs best and how the different starting points affect the final results. After the optimized design is found, the full wrapping and deployment simulation is completed to analyze the behavior of the optimized design. / Master of Science / Spacecraft are launched into space using launch vehicles. There is limited room inside the launch vehicle for the spacecraft, but the spacecraft often needs large components like solar panels, antennas, and booms to complete the mission. These components must be designed in a way that allows them to be stowed in a smaller space. This can be accomplished by designing a system that can change the configuration of the component once the spacecraft is in orbit. This is referred to as a deployable structure, and the objective of this research is to create an optimization method for designing this type of structure. This is challenging because both the stowed and deployed configurations must be considered during the optimization. HEEDS, a commercial optimization software, and ABAQUS, a commercial structural analysis software, are used to evaluate and optimize the structure in a single simulation. The optimization objectives, design variables, and constraints are chosen to fit the mission requirements of the structure. The structure examined in this research is a composite tube with a compressible cross-section wrapped around a cylinder. As the tube is wrapped, it flattens, reducing the bending stiffness so the tube can be wrapped without damaging the material. The variables controlling cross-section shape and the thickness of the composite material layers will be altered during the optimization. The maximum strain energy stored in the wrapped tube, the volume of the tube, and the minimum weight of the tube are the objectives for the optimization. The strain energy is maximized to get the stiffest possible tube when it is unwrapped to ensure there is enough stored energy to facilitate the full deployment and to satisfy the minimum natural frequency constraint. The weight and volume of the tube are minimized because reducing weight and volume is important for any spacecraft structure. Constraints are placed on the design variables and objectives and the Hashin damage criteria are used to ensure wrapping does not cause material failure. The Hashin damage criteria use the strength of the material and the stresses on the material to determine if it is likely to fail. Three optimization runs with different starting points are completed for both the SHERPA and genetic algorithm optimization methods. The results are compared to determine which optimization method performs best and how the different starting points affect the final results. After the optimized design is found, the full wrapping and deployment simulation is completed to analyze the behavior of the optimized design.