Depuis ses débuts, la conception des convertisseurs électromécaniques se limitait à l'optimisation, par l'électrotechnicien, de la conversion d'énergie électrique en énergie mécanique. Cette énergie, alors fournie sous la forme quasi exclusive d'un mouvement à un seul degré de liberté, le plus souvent rotatif, devait ensuite être adaptée, par les mécaniciens, aux besoins du système à actionner. Aujourd'hui, grâce aux évolutions récentes dans des domaines aussi variés que l'électronique de puissance, l'informatique ou encore la conception et la fabrication assistées par ordinateur, il est devenu possible de concevoir de nouveaux actionneurs directement en fonction des besoins des applications auxquelles ils sont destinés. Ainsi, des actionneurs pouvant posséder plusieurs degrés de liberté, tant en rotation qu'en translation, ont été développés. Dans ce contexte, cette thèse poursuit deux objectifs. Le premier est de proposer une démarche de conception intégrant au mieux les aspects électriques et mécaniques de systèmes électromécaniques tels que ces nouveaux actionneurs. Plus largement, elle a pour vocation de s'appliquer à tous types de problèmes multidisciplinaires où la prise en compte des différentes disciplines et de leurs interactions est indispensable pour assurer les performances globales du produit final. Plus particulièrement, elle est adaptée aux cas de recherches qui, contrairement aux cas de développements, font parfois intervenir des concepts mal maîtrisés. Le second objectif est d'appliquer cette démarche à la conception d'un actionneur électrique dont le rotor, de forme sphérique, est actionné avec un débattement illimité selon deux des trois degrés de liberté qu'il possède en rotation. Suivant les différentes étapes constituant cette démarche, divers concepts de solution sont d'abord générés, tant pour les aspects électriques d'actionnement que pour les aspects mécaniques de guidage. Ces concepts sont ensuite caractérisés, via une série de modélisations et d'expérimentations, avant d'être combinés en vue de produire une solution globale, dimensionnée, fabriquée et validée sur un banc d'essai. / From the outset, the design of electromechanical converters was limited to the optimization, by electrical engineers, of the conversion of electrical energy to mechanical energy. The latter was at that time nearly exclusively provided under the form of single degree of freedom motion, more often rotary, and had to be adapted, by mechanical engineers, to the needs of the system to be actuated. Today, thanks to recent evolutions in fields as various as power electronics, computer capabilities or computer-aided design and manufacturing (CAD-CAM), it has become possible to design new actuators by taking directly into account the needs of the applications they are intended for. As a result, actuators with several degrees of freedom, both in rotation and in translation, have been developed. Within this context, this thesis pursues two objectives. The first consists in proposing a new design method integrating as best as possible the electrical and mechanical aspects of electromechanical systems such as these new actuators. More broadly, its vocation is to be applicable to all multidisciplinary problems where taking into account each discipline and their interactions are necessary to ensure the global performances of the final product. More particularly, this method is adapted to the case of researches that, contrary to the case of other developments, sometimes includes badly mastered concepts. The second aim is to apply this approach to the design of an electrical motor with a spherical rotor actuated, with an unlimited angular range, along two of the three degrees of freedom it possesses in rotation. Following the basic steps involved in this approach, various solution concepts were first generated both for the electrical actuation aspects and the mechanical guiding aspects. These concepts were then characterized, via a number of modeling and experimentation phases, before being combined in order to obtain a global solution, which was then sized, manufactured and validated on a test bench.

In this study analysis and design procedures of partially compliant mechanisms using two degree of freedom mechanism model are developed. The flexible segments are modeled as revolute joints with torsional springs. While one freedom is controlled by the input to the mechanism, the motion of the parts are governed both by the kinematics and the force balance. The procedure developed for the analysis of such mechanisms is shown on two different mechanisms: a five link mechanism with crank input and slider output (five-bar mechanism) / a five link mechanism with crank input and rocker output. Design charts are prepared according to output-link oscillation and dimensionless design parameters

After September 11, 2001, government officials and the engineering community have devoted significant time and resources to protect the country from such attacks again. Because highway infrastructure plays such a critical role in the public’s daily life, research has been conducted to determine the resiliency of various bridge components subjected to blast loads. While more tests are needed, it is now time to transfer the research into tools to be used by the design community. The development of Anti-Terrorism Planner for Bridges (ATP-Bridge), a program intended to be used by bridge engineers and planners to investigate blast loads against bridges, is explained in this thesis. The overall project goal was to build a program that can incorporate multiple bridge components while still maintaining a simple, user-friendly interface. This goal was achieved by balancing three core areas: constraining the graphical user interface (GUI) to similar themes across the program, allowing flexibility in the creation of the numerical models, and designing the data structures using object-oriented programming concepts to connect the GUI with the numerical models. An example of a solver (prestressed girder with advanced SDOF analysis model) is also presented to illustrate a fast-running algorithm. The SDOF model incorporates the development of a moment-curvature response curve created by a layer-by-layer analysis, a non-linear static analysis accounting for both geometric non-linearity as well as material non-linearity, and a Newmark-beta-based SDOF analysis. The results of the model return the dynamic response history and the amount of damage. ATP-Bridge is the first software developed that incorporates multiple bridge components into one user-friendly engineering tool for protecting bridge structures against terrorist threats. The software is intended to serve as a synthesis of state-of-the-art knowledge, with future updates made to the program as more research becomes available. In contrast to physical testing and high-fidelity finite element simulations, ATP-Bridge uses less time-consuming, more cost effective numerical models to generate dynamic response data and damage estimates. With this tool, engineers and planners will be able to safeguard the nation’s bridge inventory and, in turn, reinforce the public’s trust. / text

No description available.

Previous research investigating the stability of the ankle joint complex may be categorised into two methodological groups, employing either an actuator to perturb the limb, or a form of standing balance disturbance such as a tilting platform, both of which test the joint in single degree of freedom (DOF). The aim of this thesis was to investigate how we control foot position and stabilise the joint when there is potential for movement in three DOF. A secondary aim of the thesis was to model the intrinsic mechanical properties of the ankle joint complex in three dimensions when coupled movement of the tibio-talar and talo-calcaneal joints are possible. This thesis details (i) the development of a perturbation rig that allows foot movement in single- or three-DOF with associated real-time visual target-matching software, and (ii) the use of the rig to investigate the stabilisation of the ankle joint complex in single- and three-DOF. The experimental procedure used a common task performed in three experimental conditions. Subjects were required to maintain a neutral foot position while developing varying levels of plantar-flexion torque. A perturbation was applied to the foot if subjects were within specified tolerance for both foot position and torque, represented by the visual display. Performance of the task in the first condition required the subject to only match torque as the foot position was fixed, with the perturbation being applied in dorsi-flexion (ie, single-DOF). The second experimental condition allowed the foot to move in the sagittal plane, hence subjects were required to control both torque and foot position in single-DOF, with perturbation applied in dorsi-flexion. The third condition enabled movement in dorsi/plantar-flexion, inversion/eversion and adduction/abduction (three-DOF) in both task and perturbation. Subjects were required to maintain the neutral foot position and the necessary torque level. There were three areas of interest common to each experimental protocol. The muscle strategy used to complete the task was investigated using a combination of surface and fine-wire electromyography on lower leg and thigh muscles. The 500ms period prior to perturbation was investigated to determine if synergies were evident between muscles such as medial and lateral gastrocnemius, soleus and peroneus longus. Two classes of activation strategies for the three-DOF condition emerged from the subject population: differential activation of the triceps surae group, and co-contraction. The former strategy may take advantage of the distinct morphology of the lateral gastrocnemius and peroneus longus muscles to best perform the position-matching component of the 3D task. The results suggest that the ankle joint is mostly stabilised in 3D by the intrinsic mechanical actions of the muscles producing plantar flexion moments. The muscles stabilised the foot in inversion, but not in eversion where there was very little motion. However, the different activation strategies employed may have varied efficacy in contributing to joint stability. This form of active stabilisation means that the previous literature focus on reflexes to stabilise the joint may need to be reassessed. Likewise, it may be appropriate to use the perturbation rig to quantify active ankle joint stability in order to assess the probability of ankle injury, rather than the current clinical measures employed. The reflexive response due to the perturbation was examined in the 200ms following perturbation. Variation in the modulation of monosynaptic reflexes was observed between subjects in various muscles in the higher DOF tasks. This is likely due to the differing activation strategies used to perform the task, and the variability in the kinematic response to perturbation. An attempt was made to calculate the intrinsic mechanical properties of the joint in 3-D using the kinematic and kinetic data during the first 15 ms period of perturbation. The system was modelled as a spring-damper using a constrained non-linear least squares, with stiffness and viscous terms for each axis, and inertial tensor elements as variables in the routine. The effect of increased muscle activation on the displacement of the foot about each of the anatomical axes was to significantly lower the movement of the sub-talar joint.

Heavy timber construction is emerging as a viable alternative to conventional building materials, such as steel and concrete, for mid- and high rise structures. With the increasing presence of timber structures at or near potential targets comes an increased risk for damage to the structure and more importantly human casualties. The current provisions related to wood in the blast code (CSA, 2012) are limited and based on general understanding of the material behaviour rather than thorough research studies. Also, the standard does not clearly distinguish between the various types of engineered wood products. A study was undertaken to assess the behaviour of cross-laminated timber panels subjected to simulated blast loading using a shock tube apparatus. More specifically, the aim of this study was to investigate the behaviour of CLT panels subjected to static and dynamic loads to determine a dynamic increase factor in order to quantify high strain rate effects on this material. Testing was completed on a total of 18 CLT panels, with panel thicknesses of 105 and 175 mm corresponding to a 3-ply and 5-ply panel, respectively. An average dynamic increase factor of 1.28 on the resistance and no apparent increase in stiffness from static to dynamic loading were observed. Two resistance material predictive models that account for high strain-rate effects and the experimentally observed post-peak residual behavior were developed. A single degree-of-freedom model was validated using full-scale simulated blast load tests, and the predictions were found to match well with the experimental displacement-time histories.

京都大学 / 0048 / 新制・課程博士 / 博士(人間・環境学) / 甲第19794号 / 人博第765号 / 新制||人||184(附属図書館) / 27||人博||765(吉田南総合図書館) / 32830 / 京都大学大学院人間・環境学研究科共生人間学専攻 / (主査)教授 神﨑 素樹, 教授 森谷 敏夫, 教授 石原 昭彦 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DGAM

<p dir="ltr">SC walls have emerged as an advantageous alternative to reinforced concrete (RC) construction for blast resistant structures. SC walls typically consist of shop fabricated steel modules which can be erected on site and filled with concrete, without additional formwork setup or removal. The steel modules typically consist of steel faceplates, tie bars between faceplates, and optional shear studs. SC members offer advantages in strength, ductility, constructability, and construction schedule when compared with RC. The behavior of SC structures have been previously demonstrated and adopted into many building design codes, but there is a knowledge gap on the post-elastic behavior of SC members in two-way bending. The desire to use SC walls for blast resistant design motivates the need to study this behavior for SC walls and slabs. In this study, the behavior of SC panels in two-way bending was evaluated by using analytical, experimental, and numerical methods.</p><p dir="ltr">Structural mechanics was used to develop simple predictions for the static behavior of rectangular, two-way SC panels under a uniform pressure loading. These predictions include the inelastic cross-section flexural capacity, the member static resistance function, the load-mass transformation factor for SDOF analysis, out-of-plane shear demands, and rotation demands. A quick-running SDOF computer algorithm was created to conduct blast load analysis incorporating the nonlinear member behavior predicted by mechanics.</p><p dir="ltr">The two-way bending behavior of a SC panel was experimentally investigated. A SC panel was fabricated and experimentally loaded in two-way bending until flexural failure of the panel was reached. A series of concentrated loads applied to the panel was designed to simulate the yield line pattern of a panel under a uniform applied pressure. The experimental test demonstrated the deformed shape, inelastic capacity, and progression of yield lines throughout a SC panel in two-way bending. A 2D, layered composite shell finite element analysis was benchmarked to the experimental results. The finite element modeled the inelastic flexural behavior of the SC panel, closely matching the capacity, deformed shape, and development of yield lines throughout the panel.</p><p dir="ltr">The finite element modeling approach was used to validate the SDOF predictions of two-way SC panel behavior under static and blast pressure loadings through a parametric study. Detailed comparisons of the two modeling results were made. Iso-damage pressure-impulse diagrams for multiple SC panel geometries were developed.</p>

No description available.

No description available.