<p>This research is concerned with CFD modelling of thermal energy storage tanks containing water with submerged phase change materials (PCM). Under appropriate operating conditions, the energy density of this hybrid system can be significantly increased (two to five times) relative to a system containing water only. However, due to low thermal conductivity of phase change materials, the geometry and configurations of the PCM capsules in the tank should be optimized. This research focused on the assessment of flat plate PCM modules submerged in a rectangular water tank. The encapsulation of the PCM within the slender flat plates resulted in a large PCM surface area and a reduction in the internal heat transfer resistance. The water was heated by coils placed at the bottom of the tank. The resulting natural convection currents acted to transfer heat from the hot coils to the PCM modules which were treated as isothermal at the PCM melt temperature. It is concluded that the charge rate of the system increases to 2.8 times by increasing the PCM volume percentage from 2.5% to 15%. However for PCM volume percentages of more than 15%, the area of the PCM became much more than the area of the coil (around 15 times) in a way that the charge rate of the system started to be controlled by the coil. In this stage, the charge rate of the system remained constant, and adding modules to the system only increased the heat capacity of the system. Therefore the charge rate of the system could only increase if the coil surface area was increased. The heat transfer coefficients of the PCM modules and coil tubes were higher than those evaluated by the experimental correlations for natural convection. This was due to the recirculation of the flow in the tank “pumping effect” created by the coil for PCM modules and by the PCM modules for the coil. It was also concluded that superheating of the PCM surface temperature decreases the heat transfer rate to the PCM significantly, and the charge rate of the system varies linearly with the temperature difference between the PCM modules and the coil.</p> / Master of Applied Science (MASc)

Total ankle replacement (TAR) implants are an effective option to restore the range of motion of the ankle joint for arthritic patients. An effective tool for analyzing these implants’ mechanical performance and longevity in-silico is finite element analysis (FEA). ABAQUS FEA was used to statically analyze the von Mises stress and contact pressure on the articulating surface of the bearing component in two newly installed fixed-bearing total ankle replacement implants (the Wright Medical INBONE II and the Exactech Vantage). This bearing component rotates on the talar component to induce primary ankle joint motion of plantarflexion and dorsiflexion. The stress response was analyzed on this bearing component since it is made of the least strong material in the implant assembly (ultra-high molecular weight polyethylene (UHMWPE). This bearing component commonly fails and is the cause for surgeon revisions. Six different FEA models for various gait percentages during stance (10%, 20%, 30%, 40%, 50%, and 60%) were created. They varied in magnitude of the compressive load and the ankle dorsiflexion/plantarflexion angle. This study captured the variation in stress magnitudes based on the portion of the stance phase. The results indicated that the stress distribution on the articulating surface increased as compressive load increased, and the largest magnitudes occurred at high dorsiflexion angles (15-30°). The von Mises stress and contact pressure tended to occur in regions where the thickness of the bearing was the least. Additionally, high contact pressures were examined in areas near the talar component's edge or at the bearing's edges. To the author’s knowledge, this is the first study available to the research community that analyzes the Vantage implant with FEA. This study lays an essential foundation for future researchers in presenting a thorough literature review of TAR and for a simple model setup to capture the stress distributions of two TAR implants. This study provides valuable information that can be beneficial to medical company designers and orthopedic surgeons in understanding the stress response of TAR patients.

Hitachi Energy, one of the largest transformer manufacturers in the world, has a factory based in the small town of Ludvika, Sweden. Here, all of the production is carried out, from order to delivery, and the key to reaching the rest of the world lies within the Swedish railway network. Utilizing specialized railway wagons, Hitachi Energy transports the transformers to the industrial ports for further export to the rest of the world. To ensure safe transportation, with loads exceeding 400 tons, transportation consoles made for this exact purpose are used to carry the transformer's weight and keep them in place during transportation. However, with their current solution having stayed the same for many years, they now aspire to a new solution for the transportation consoles to fulfill both the physical and human-centered demands better. In this master's thesis, in industrial design engineering, a new solution for transportation consoles is being developed. To ensure the quality of the project, a design process with four stages - a learning phase, an ideation phase, a development phase, and a delivery phase - has been used. Three research questions have been in focus during the project:  What are the needs and requirements for the new transportation console? How can we identify both user needs and product requirements for the new transportation consoles through an industrial design engineering approach? How would a completely new solution for transportation consoles be designed and used in detail?  Several industrial design methods have been utilized in these phases to gain a broad knowledge of the problem and generate ideas. A product cycle analysis was conducted based on interviews and observations to better understand the product. When the knowledge was gathered, several brainstorming methods, scamper, and virtual prototyping were used to generate several new solutions and ideas. To test and develop the concepts in detail, computer-aided engineering has been used, with computer-aided design to virtually prototype the concepts and finite element analysis to verify them. The learning phase showed the need for a more user-friendly solution and how a slimmer console profile could improve the workers' overall experience. Multiple concepts of solving these problems in different ways were found in the ideation phase. After design reviews with the stakeholders and consultation with the supervisors, a final concept, Arc, for a new transportation console was chosen to continue with into the two later stages of the process. Arc's foundation lies within a human-centered design and the people interacting with it weekly. It has several advantages compared to the previous design, with its adjustability and slim design facilitating the workload and enabling easier transportation. Analyses of its durability against external accelerations have been conducted, leaning towards a promising outcome. However, further testing and verifications are needed to ensure its durability before use.

Cette thèse porte sur le développement d'outils permettant le recalage d'images d'une surface déformable et la reconstruction tridimensionnelle de surfaces déformables à partir d'images prises par une seule caméra. Les surfaces que nous souhaitons traiter sont typiquement un visage ou une feuille de papier. Ces problématiques sont mal posées lorsque seule l'information présente dans les images est exploitée. Des informations a priori sur les déformations physiquement admissibles de la surface observée doivent être définies. Elles diffèrent en fonction du problème étudié. Par exemple, pour une feuille de papier, la courbure Gaussienne évaluée en chacun de ces points est nulle, cette propriété n'est pas valide pour un visage. Les applications visées sont l'insertion réaliste de logo 2D, de texte et aussi d'objets virtuels 3D dans des vidéos présentant une surface déformable. La première partie de cette thèse est consacrée au recalage d'images par modèles déformables. Après avoir brièvement introduit les notions de base sur les fonctions de déformation et sur leur estimation à partir de données images, nous donnons deux contributions. La première est un algorithme de recalage d'images d'une surface déformable, qui est efficace en terme de temps de calcul. Nous proposons une paramétrisation par primitives des fonctions de déformation permettant alors leur estimation par des algorithmes compositionnels habituellement réservés aux transformations formant un groupe. La deuxième contribution est la modélisation explicite des auto-occultations, en imposant la contraction de la fonction de déformation le long de la frontière d'auto-occultation. La deuxième partie de cette thèse aborde le problème de la reconstruction tridimensionnelle monoculaire de surfaces déformables. Nous nous basons sur le modèle de faible rang : les déformations sont approximées par une combinaison linéaire de modes de déformation inconnus. Nous supposons que ces derniers sont ordonnés par importance en terme d'amplitude de déformation capturée dans les images. Il en résulte une estimation hiérarchique des modes, facilitant l'emploi d'un modèle de caméra perspectif, la sélection automatique du nombre de modes et réduisant certaines ambiguïtés inhérentes au modèle. Nous explorons finalement la capture des déformations d'une surface peu texturée à partir de données issues d'un capteur 3D. L'information présente au niveau des contours de la surface est notamment utilisée. Nous avons implanté les différentes contributions décrites ci-dessous. Elles sont testées et comparées à l'état de l'art sur des données réelles et synthétiques. Les résultats sont présentés tout au long du tapuscrit.

Les entreprises collaborent pour saisir des opportunités, échanger des documents et ressources, cela en suivant des processus métier pouvant évoluer. Les portails collaboratifs sont une solution orientée web à ce besoin de collaboration. Cependant, la conception et la maintenance d'un portail collaboratif métier n'est pas trivial et reste peu accessible aux acteurs de l'entreprise. Cela a comme conséquence la difficulté de maintenir et faire évoluer le portail collaboratif sans que cela ne soit trop coûteux en temps et financièrement. Afin de répondre à cette problématique, une solution consiste à capter les besoins métier de la collaboration dans un modèle, puis générer automatiquement le portail collaboratif correspondant. Le modèle, dans ce cas, doit être accessible aux acteurs métier et expressif décrivant ainsi les aspects les plus complexes d'une collaboration. C'est dans ce contexte que se situent nos travaux. À défaut d'avoir une solution toute faite, nous avons mis en place une approche de conception de portail collaboratif fondée sur l'Ingénierie Dirigée par les Modèles. Pour la description de nos portails, nous avons choisi de privilégier la modélisation des entreprises centrée sur les processus métier comme point de départ. Notre solution repose sur notre métamodèle MACoP (Modeling and Analysis of Collaborative Portal). Dans ce métamodèle nous avons fait cohabiter l'accessibilité et l'expressivité. Cela en proposant de nouveaux concepts permettant ainsi la génération complète des portails collaboratifs. Le métamodèle MACoP est accompagné d'une chaîne de transformations permettant de passer directement d'un modèle MACoP au code Python du portail collaboratif.

An anguilliform swimming robot replicating an idealized motion is a complex marine vehicle necessitating both a theoretical and experimental analysis to completely understand its propulsion characteristics. The ideal anguilliform motion within is theorized to produce ``wakeless'' swimming (Vorus, 2011), a reactive swimming technique that produces thrust by accelerations of the added mass in the vicinity of the body. The net circulation for the unsteady motion is theorized to be eliminated. The robot was designed to replicate the desired, theoretical motion by applying control theory methods. Independent joint control was used due to hardware limitations. The fluid velocity vectors in the propulsive wake downstream of the tethered, swimming robot were measured using Particle Image Velocimetry (PIV). Simultaneously, a load cell measured the thrust (or drag) forces of the robot via a hydrodynamic tether. The measured field velocities and thrust forces were compared to the theoretical predictions for each. The desired, ideal motion was not replicated consistently during PIV testing, producing off-design scenarios. The thrust-computing method for the ideal motion was applied to the actual, recorded motion and compared to the load cell results. The theoretical field velocities were computed differently by accounting for shed vortices due to a different shape than ideal. The theoretical thrust shows trends similar to the measured thrust over time. Similarly promising comparisons are found between the theoretical and measured flow-field velocities with respect to qualitative trends and velocity magnitudes. The initial thrust coefficient prediction was deemed insufficient, and a new one was determined from an iterative process. The off-design cases shed flow structures into the downstream wake of the robot. The first is a residual disturbance of the shed boundary layer, which is to be expected for the ideal case, and dissipates within one motion cycle. The second are larger-order vortices that are being shed at two distinct times during a half-cycle. These qualitative and quantitative comparisons were used to confirm the possibility of the original hypothesis of ``wakeless'' swimming. While the ideal motion could not be tested consistently, the results of the off-design cases agree significantly with the adjusted theoretical computations. This shows that the boundary conditions derived from slender-body constraints and the assumptions of ideal flow theory are sufficient enough to predict the propulsion characteristics of an anguilliform robot undergoing this specific motion.

The focus of this thesis is to explore the automation technology used in the modern entertainment industry. Upon completion of my thesis, I will deliver a working prototype of the chosen technology and present its capabilities in a choreographed show.

This thesis presents a real-time autonomous guidance and control method for a quadrotor in a GPS-denied environment. The quadrotor autonomously seeks a destination while it avoids obstacles whose shape and position are initially unknown. We implement the obstacle avoidance and destination seeking methods using off-the-shelf sensors, including a vision-sensing camera. The vision-sensing camera detects the positions of points on the surface of obstacles. We use this obstacle position data and a potential-field method to generate velocity commands. We present a backstepping controller that uses the velocity commands to generate the quadrotor's control inputs. In indoor experiments, we demonstrate that the guidance and control methods provide the quadrotor with sufficient autonomy to fly point to point, while avoiding obstacles.

This thesis introduces a new methodology for robust form parameter design of complex hull form geometry via constraint programming, automatic differentiation, interval arithmetic, and truncated hierarchical B- splines. To date, there has been no clearly stated methodology for assuring consistency of general (equality and inequality) constraints across an entire geometric form parameter ship hull design space. In contrast, the method to be given here can be used to produce guaranteed narrowing of the design space, such that infeasible portions are eliminated. Furthermore, we can guarantee that any set of form parameters generated by our method will be self consistent. It is for this reason that we use the title feasible form parameter design. In form parameter design, a design space is represented by a tuple of design parameters which are extended in each design space dimension. In this representation, a single feasible design is a consistent set of real valued parameters, one for every component of the design space tuple. Using the methodology to be given here, we pick out designs which consist of consistent parameters, narrowed to any desired precision up to that of the machine, even for equality constraints. Furthermore, the method is developed to enable the generation of complex hull forms using an extension of the basic rules idea to allow for automated generation of rules networks, plus the use of the truncated hierarchical B-splines, a wavelet-adaptive extension of standard B-splines and hierarchical B-splines. The adaptive resolution methods are employed in order to allow an automated program the freedom to generate complex B-spline representations of the geometry in a robust manner across multiple levels of detail. Thus two complementary objectives are pursued: ensuring feasible starting sets of form parameters, and enabling the generation of complex hull form geometry.

Abstract An experimental method was developed that demonstrated the size effects in forming thin sheet metals, and a finite element model was developed to predict the effects demonstrated by the experiment. A universal testing machine (UTM) was used to form aluminum and copper of varying thicknesses (less than 1mm) into a hemispherical dome. A stereolithography additive manufacturing technology was used to fabricate the punch and die from a UV curing resin. There was agreement between the experimental and numerical models. The results showed that geometric size effects were significant for both materials, and these effects increased as the thickness of the sheets decreased. The demonstration presents an inexpensive method of testing small-scale size effects in forming processes, which can be altered easily to produce different shapes and clearances.