A novel active material for controllable, high work density applications was designed, fabricated, analyzed, and tested. This active material uses a lens-shaped element to implement simple shear motion with gas pressure actuation. The lens element is a bladder-filled Kevlar fabric embedded in a polyurethane matrix. The polyurethane’s hyperelastic material parameters were found by experiment and estimated by numerical analysis. The Ogden material constant set found shows good agreement within the shear actuator’s working range. A fabricated, single-element shear actuator reached 34.2% free shear strain when pressurized to 1.03 MPa. A unitary shear actuator was modeled as were single-acting and dual-acting shear actuator arrays so that solitary and multi-cell behaviors were estimated. Actuator work performance and power from nonlinear finite element analysis found conventional work density is 0.2289 MJ/m3 and 0.2482 MJ/m3, for the singleacting and double-acting shear actuator, respectively. Scientific work densities are 0.0758 MJ/m3 and 0.0375 MJ/m3, for single-acting and double-acting shear actuators, respectively. Calculation shows the volumetric power for a single-acting shear actuator is 0.4578 MW/m3 and 0.4964 MW/m3 for the double-acting shear actuator. Finally, a nastic actuator is applied to twist a generic structural beam. The nasticmaterial actuated structure has an advantage over conventional actuator systems. Work per unit volume for nastic materials is 2280~8471% higher than conventional, discrete actuators that use electric motors. When compared by work per unit mass, this nastic actuator is 2592~13900% better than conventional actuator because nastic actuator is made from lighter materials and it distributes the actuation throughout the structure, which eliminates connecting components. The nastic actuator’s volumetric power is 2217~8602% higher than conventional actuators. Finally, the nastic actuator is 2656~14269% higher than conventional actuators for power per unit mass.

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Hospital environments are ranked as one of the most stressful contemporary work environments for their employees, and this especially concerns nurses (Nejati et al. 2016). One of the core problems comprises the notion that the current technology adopted in hospitals does not support the mobile nature of medical work and the complex work environment, in which people and information are distributed (Bardram 2003). The employment of inadequate technology and the strenuous access to information results in a decrease in efficiency regarding the fulfilment of medical tasks, and puts a strain on the attention of the medical personnel. This thesis proposes a solution to the aforementioned problems through the design of ambient displays, that inform the medical personnel with the health statuses of patients whilst requiring minimal allocation of attention. The ambient displays concede a hierarchy of information, where the most essential information encompasses an overview of patients’ vital signs. Data regarding the vital signs are measured by biometric sensors and are embodied by shape-changing interfaces, of which the ambient displays consist. User-authentication permits the medical personnel to access a deeper layer within the hierarchy of information, entailing clinical data such as patient EMRs, after gesture-based interaction with the ambient display. The additional clinical information is retrieved on the user’s PDA, and can subsequently be viewed in more detail, or modified at any place within the hospital.In this thesis, prototypes of shape-changing interfaces were designed and evaluated in a hospital environment. The evaluation was focused on the interaction design and user-experience of the shape-changing interface, the capabilities of the ambient displays to inform users through peripheral awareness, as well as the remote communication between patient and healthcare professional through biometric data. The evaluations indicated that the required attention allocated for the acquisition of information from the shape-changing interface was minimal. The interaction with the ambient display, as well as with the PDA when accessing additional clinical data, was deemed intuitive, yet comprised a short learning curve. Furthermore, the evaluations in situ pointed out that for optimised communication through the ambient displays, an overview of the health statuses of approximately eight patients should be displayed, and placed in the corridors of the hospital ward.

Cette thèse s’intéresse au rapport entre la forme et la géométrie d’un objet. Elle s’articule autour de 3 chapitres. Dans le premier, nous utilisons des "polymères électro-actifs", des systèmes capables de se déformer dans le plan lorsqu’ils sont soumis à un champ électrique,pour mimer une sorte de croissance biologique. Nous avons regardé comment une croissance inhomogène pouvait déclencher une instabilité de flambage dans une plaque électro-active.Nous avons ensuite cherché à contrôler de manière locale la croissance, dans l’espoir d’obtenir des objets capables de changer de forme sur commande. Dans le deuxième chapitre, nous nous avons étudié un problème inverse : au lieu de chercher à donner une nouvelle forme naturelle à l’objet, nous le forçons à adopter une forme qui ne lui est pas naturelle. Nous avons aplati des coques élastiques hémisphériques. La transformation d’une sphère en plan n’étant pas isométrique, cette opération crée des contraintes dans l’objet. Il se produit alors une instabilité mécanique que nous avons étudiée. Enfin, nous nous sommes penchés sur le problème des "lentilles de contact" en nous demandant si l’on pouvait coller l’une sur l’autre deux portions de sphères ayant des courbures différentes. Ici encore, la différence de courbure de Gauss entre les deux surfaces conduit à des motifs d’instabilités dans la coque élastique / From a general point of view, my thesis deals with the links between the geometry and the shape of an object. It is composed of three main chapters. In the first one, we use "electro-active polymers", systems that undergo planar expansion when submitted to an electric field, to mimic a kind of biological growth. We looked at how an inhomogeneous growth can trigger buckling instability in this electro-active plate. We then tried to control locally this growth, hoping to create objects that can change shape on command. In the second chapter, we studied the opposite problem: instead of giving it a new natural shape, we force the object in adopting a non natural shape. We squashed hemispherical elastic caps. Changing a sphere into a plane is not an isometrical transformation, this operation thus creates strains in the object. We studied the mecanical instability hence produced. Finally we focused on the "contact lens" problem by wondering if it is possible to stick two spherical caps having different curvature. Here again, the mismatch of Gaussian curvature leads to patterns of instability in the elastic shell

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Au milieu des espaces collectifs et publics, les afficheurs cylindriques informent les utilisateurs autour d'eux. Nous questionnons l'utilité et l'utilisabilité de la symétrie dynamique de révolution pour les afficheurs cylindriques à changement de forme. Nous présentons CairnFORM, un prototype d'afficheur cylindrique capable de changer de symétrie de révolution à l'aide d'une pile modulaire d'anneaux extensibles illuminés. Nous montrons que la symétrie de révolution est utilisable pour informer les utilisateurs par physicalisation des données : nous observons avec un CairnFORM à 10 anneaux qu'un histogramme à anneaux physiques est plus efficace pour une tâche d'intervalle et une tâche de comparaison plutôt que pour une tâche d'ordonnancement. Nous montrons que le changement de symétrie de révolution est utilisable pour notifier sans déranger les utilisateurs par interaction périphérique : nous observons avec un CairnFORM à 1 anneau que le changement de diamètre d'un anneau avec une vitesse exponentielle est perçu plus souvent et plus calmement en périphérie de l'attention plutôt qu'avec une vitesse constante ou logarithmique. Nous montrons que les afficheurs cylindriques à symétrie dynamique de révolution offrent une expérience utilisateur sur la durée supérieure aux afficheurs planaires : après deux mois en contexte d'usage sur un lieu de travail, nous observons que CairnFORM est aussi pragmatique mais plus hédonique qu'un écran plat. Nous étudions un cas d'usage pour les afficheurs sur le lieu de travail, c'est-à-dire aider les employés à décaler le chargement de batterie des ordinateurs portables vers les heures de pic de production locale d'énergie renouvelable. / In the middle of public and collective spaces, cylindrical displays inform users around them.We question the utility and the usability of dynamic revolution symmetry for shape-changing cylindrical displays. We present CairnFORM, a prototype of cylindrical display that can change its revolution symmetry using a modular stack of expandable illuminated rings.We show that revolution symmetry is usable for informing users through data physicalization: We observe with a 10-ring CairnFORM that a physical ring chart is more efficient for a range task and for a compare task rather than for an order task. We show that revolution symmetry change is usable for unobtrusively notifying users through peripheral interaction: We observe with a 1-ring CairnFORM that a ring diameter change with exponential speed is perceived more often and calmer in the periphery of attention rather than with a constant speed or a logarithmic speed.We show that cylindrical displays with dynamic revolution symmetry offer a greater user experience over time than planar displays: After two months in context of use in a workplace, we observe that CairnFORM is as pragmatic as a flat screen but more hedonic than a flat screen. We study a use case for displays in the workplace: Helping employees to shift laptop battery charge to peak hours of local renewable energy production.

Deep touch pressure is used to treat sensory processing difficulties by applying a firm touch to the body to stimulate the nervous system and soothe anxiety. I conducted a long-term exploration of deep touch pressure from a first-person perspective, using shape-changing pneumatic actuators, breathing and ECG sensors to investigate whether deep touch pressure can guide users to engage in semi-autonomous interactions with their breathing and encourage greater introspection and body awareness. Based on an initial collaborative material exploration, I designed the breathing garment- a wearable vest used to guide the wearer through deep breathing techniques. The breathing garment presents a new use case of deep touch pressure as a modality for hapticbreathing feedback, which showed potential in supporting interoceptive awareness and relaxation. It allowed me to engage in a dialogue with my body, serving as a constant reminder to turn inwards and attend to my somatic experience. By pushing my torso forward, the actuators were able to engage my entire body while responding to my breath, creating a sense of intimacy, of being safe and taken care of. This work addresses a gap in HCI research around deep touch pressure and biosensing technology concerning the subjective experience of their emotional and cognitive impact. The longterm, felt engagement with different breathing techniques opened up a rich design space around pressure-based actuation in the context of breathing. This rendered a number of experiential qualities and affordances of the shape-changing pneumatic actuators, such as: applying subtle, slowly changing pressure to draw attention to specific body parts, but also disrupting the habitual way of breathing with asynchronous and asymmetric actuation patterns; taking on a leading or following role in the interaction, at times both simultaneously; and acting as a comforting companion or as a communication channel between two people as well as between one person and their soma. / Djuptrycksterapi (Deep Touch Pressure, DTP) används för att behandla personer som har problem med att processa sensoriska upplevelser. Detta genom att applicera ett fast tryck på kroppen för att aktivera nervsystemet och lindra ångest. Jag genomförde en långtidsutforskning av DTP ur ett första-persons-perspektiv, med hjälp av formförändrande tryckluftsaktuatorer, andnings sensorer och EKG-elektroder. Dess syfte var att undersöka ifall DTP kan guida användare till att engageras i semiautonoma interaktioner med sin andning och främja en större introspektion och kroppsmedvetenhet. Baserat på ett initialt samarbete kring undersökning av olika material, designade jag “the breathing garment” - en bärbar väst som guidar användaren genom djupandningstekniker. Andningsvästen visar på en ny användning av DTP som en modalitet av haptisk andningsfeedback, och den möjliggör ett stödjande av interoceptisk medvetenhet och avslappning. Andningsvästen tillät mig att delta i en dialog med min egen kropp, och fungerade som en ständig påminnelse att vända mig inåt och uppmärksamma mina somatiska upplevelser. Genom att trycka min bröstkorg framåt kunde aktuatorerna engagera hela min kropp när de svarade mot min andning, vilket skapade en känsla av intimitet, trygghet och att vara omhändertagen. Detta examensarbete uppmärksammar ett område som tidigare varit outforskat inom HCI av djuptrycksterapi och biosensorteknik kring den subjektiva upplevelsen av dess emotionella och kognitiva påverkan. Det långvariga engagemanget med aktivt upplevande av olika andningstekniker öppnade upp en stor designrymd kring tryckbaserade aktuatorer i en kontext av andning. Det visar på ett flertal experimentella kvaliteter och affordances av de formförändrande tryckluftsaktuatorerna, såsom: att applicera ett gradvis ökande och markant tryck för att dra uppmärksamheten till specifika kroppsdelar, men också för att bryta det vanliga andningsmönstret genom asynkron och asymmetrisk mönsterpåverkan; att ta en ledande eller följande roll i interaktionen, ibland båda samtidigt; och att agera som en tröstande följeslagare, eller som en kommunikationskanal mellan två människor, likväl som mellan en person och hennes soma.