The purpose of this research is the development of design concepts and models of large-angle, compliant, multistable, revolute joints. This research presents evidence of the capability of these models and concepts by presenting a case study in which the miniaturization of revolute joints are examined. Previous attempts at multistable revolute joints can be categorized into two categories: compliant and non-compliant mechanisms. Non-compliant multistable revolute joints are typified by a combination of pin-in-slot joints, springs, and detents. Due to factors inherit in design, noncompliant joints often succumb to friction, wear, and undesirable motion, that leads to a decline in performance. Compliant multistable joints, such as those discussed in this work, negate these issues by allowing deflection in one or more of their members. However, compliant mechanisms have challenges associated with large-angle revolutions, stress concentration, and, historically, they perform poorly in compression. The literature has been lacking information on the fabrication of compliant multistable revolute joints having more than two stable positions. This work develops a truly multistable compliant revolute joint that is capable of multiple stable positions, the multistable compliant rolling-contact element(CORE). A CORE is a contact-aided complaint mechanism that eliminates friction and wear by allowing two surfaces to roll on each other. Furthermore, the contact eliminates problems such as poor performance in compression, typically associated with compliant mechanisms. The device uses minima in potential energy to achieve multi-stability, through one of six mechanisms. The use of minima in the potential energy eliminates the need for detents and other fatigue prone devices. Multistability may be achieved by placing the CORE flexure into tension or using flexible segments attached to the foci; or by changing the initial curvature of the flexure, curvature of the CORE surface, cross sectional area of the flexure (both protagonistically or antagonistically), or material properties. The stability methods are evaluated via a Pugh scoring matrix and the most promising concept, stability through tension in the CORE flexures, examined further. The utility of mathematical models, developed in this work, that predict stress, strain, and activation force, are demonstrated via a case study. This work also demonstrates that the device is capable of large angle deflections (360) and that the provided models permit efficient engineering design with COREs.

Thin structures exist as one dimensional slender objects (hairs, tendrils, telephone cords, etc.) and two dimensional thin sheets (tree leaves, Mobius bands, eggshells, etc.). Geometric and material nonlinearities can conspire together to create complex phenomena in thin structures. This dissertation studies snap-through, multi-stability, and localization in thin rods and sheets through a combination of experiments and numerics. The first work experimentally explores the multi-stability and bifurcations of buckled elastic strips subject to clamping and lateral end translations, and compares these results with numerical continuation of a perfectly anisotropic Kirchhoff rod model. It is shown that this naive Kirchhoff rod model works surprisingly well as an organizing framework for thin bands with various widths. Thin sheets prefer to bend rather than to stretch because of the high cost of stretching energy. Knowing the bending response of thin sheets can aid in simulating deformations such as creasing. The second work introduces an exact pure bending linkage mechanism for potential use in a bend tester that measures the moment-curvature relationship of soft sheets and filaments. Mechanical rotary pleating is a bending-deformation-dominant process that deforms nonwoven materials into zigzag filter structures. The third work studies what combinations of processing and material parameters lead to successful rotary pleating. The rotary pleating process is formulated as a multi-point variable-arc-length boundary value problem for an inextensible rod, with a moment-curvature constitutive law, such as might be measured by a bend tester, as input. Through parametric studies, this work generates pleatability surfaces that may help avoid pleating failure in the real pleating process. Creased thin sheets are generally bistable. The final work of this dissertation studies bistability of creased thin disks under the removal of singularities. A hole is cut in the disk and, through numerical continuation of an inextensible strip model, this work studies how the crease stiffness, crease angle, and hole geometry affect the bistability. / Doctor of Philosophy / Thin structures are those that have at least one dimension smaller than the other dimensions, such as hairs, telephone cords, and tree leaves, to name just a few. They can generate rich mechanical behaviors (e.g., snapping, crumpling) and complex shapes. A simple example is to rotate the two ends of a thin strip that has been deformed into an arch. Snapping will happen at a certain rotation angle. The first work studies snapping behaviors of thin bands subject to rotations and displacements at the two ends. This work employs a mechanical model based on force and moment balance on a spatial curve to solve the shapes of thin strips and capture the rich snapping behaviors. It is much harder to stretch a thin sheet than to bend it, which can be easily seen by deforming a piece of paper. The physics behind this is that stretching requires more energy than bending in thin objects. Knowing the bending response of thin sheets can aid in simulating deformations of thin structures. The second work introduces a new pure bending mechanism that can subject a sheet to pure bending and measure its bending response through a moment-curvature relationship. Thin sheets find broad applications in engineering. Mechanical pleating is a long-standing technique that deforms thin sheets into zigzag filter structures, but the mechanics behind it is unclear. The third work studies a rotary pleating process and aims to answer a basic question: What combinations of processing and material parameters lead to successful pleating? This work employs a one-dimensional model of an inextensible rod, with a moment-curvature constitutive law as input. The moment-curvature relationship of pleating materials can be measured by the pure bending mechanism developed in the second work. Thin sheets with prescribed crease patterns can create complicated and targeted shapes, such as origami (paper folding) and kirigami (paper cutting). A simple creased thin sheet is bistable: A stable configuration can be obtained by inverting the crease, which leads to a conical vertex/singularity. The fourth work of this dissertation finds that the bistability of creased thin sheets will be destroyed if a large hole is made around the vertex. This work studies the loss of bistability of creases under removal of singularities by quantifying how the hole size, hole geometry, and other factors such as the crease angle and crease stiffness affect the bistability.

This thesis is about expanded narrative, a new field of experimental narrative practices that are not represented by single subjects or by categories such as ‘interactive’. It is defined by works that present a challenge to the form, fiction or nonfiction, in terms of the content, structure, style of writing or audience engagement. Extending the cognitive term ‘perceptual multistability’, that refers to switching between interpretations experienced when we look at an ambiguous figures, such as, the Necker cube, this thesis develops the position that expanded narrative practices and specifically locative narrative, a genera of expanded narrative, hold the potential to prompt the experiential effects of multi-stability. The metaphor of multi-stability introduced here stands in for three aspects of experience: language, perception and belief. While ambiguity and misperceptions have been recognised in the literature of experiential narrative practices, further exposition is required. The thesis asks what are the conditions in which the qualities of the metaphor of multi-stability may be prompted and what framework usefully articulates the parameters of experience? Drawing upon the writings of the philosopher William James, subsequent pragmatists, cognitive neuroscience and narratology, it explores how a radical empiricist perspective can form the basis of a non-foundational experiential framework that questions the status of knowledge and the problems of translation between experience and narrative interpretation. It suggests that the subjective classification of imagined and perceptual objects can be affected by the relations between the narrative form, the environment and the participant’s beliefs. The major contributions of the thesis are (1) the development of the Jamesian experiential framework that sets up cross-disciplinary parameters for the thematics of experience to engage with the ontological and epistemological challenges of evaluating and designing for multistability presents; (2) a relational approach to interpretation and coding participants’ feedback of locative narratives; (3) that is employed in the development of a collection of speculative strategies for evoking the effect of the metaphor of multi-stability, based on the development of four published locative narrative apps and ten prototypes. While highly contingent, participant introspective accounts of experience are central here to the methodology, the process of serial hypothesis forming and the iterative development of prototypes and locative narrative case studies. This research does not attempt to draw causal connections from science to that of narrative experience or vice versa. The thesis first considers the field of expanded narrative and the semantic and pragmatic framings of the term narrative and narratological framings of language as multi-stable. It goes on to examine the antecedent and coexistent practices of locative narrative. The epistemological implications for misperception, the function of representation and intentionality in perception are examined in relation to the environmentally situated perceptual, interpretative, aesthetic and emotional dimensions of experience. This research contributes to research in narrative and creative practices. It extends the form of locative narrative with the concept of multi-stability that has a wider application with the field of expanded narrative, creative practice and narratology.