The advent of finite element methods has changed the tire industry's design process over the past three decades. Analyses, previously impractical using analytical methods and physically limited by experimental methods, can now be performed using computational methods. This decreases the cost and time associated with bringing a new design to the marketplace; however some physical testing is still required to validate the models. The design, fabrication, installation, and operation of a tire, suspension, and chassis test fixture (TiSCTeF) is detailed as part of this study. This fixture will support the validation of effective, parametric finite element models currently under development, as well as the design and testing of suspension and chassis components for the Virginia Tech Formula SAE team. The fixture is designed to use the Formula SAE race car as the test platform. Initially, the fixture is capable of performing static load-deflection and free-rolling tire tests. Provision has been made in the design for incremental upgrades to support cornering tests and additional instrumentation. An initial load-deflection test has proven that the fixture is capable of creating reproducible data sets. Specific recommendations are made concerning the improvement of data quality for future tests. This study also presents a process for analyzing existing tire cornering data and eliminating anomalies to improve the effectiveness of normalization techniques found in the literature. The process is shown to collapse tire cornering data, which is partially ill- conditioned, onto master curves that consistently display the effect of inclination angle and tire inflation pressure on tire response. / Master of Science

Tire testing has been one of the important aspects of the tire industry because it helps identify the tire behavior which further helps in improving the design of tires. It also helps automotive manufacturers choose the best tire for their automobiles. Indoor tire testing helps in relating the data better because of greater repeatability of the testing setup as compared to outdoor testing. This study focusses on modifying a rolling resistance machine to make it capable of force and moment and cleat testing along with the standard rolling resistance test. Additionally, the design of a mechanical loading mechanism (used to apply normal force on the tire) in place of the previous one using dead weights is also discussed. This study also talks about the structural and vibrational finite element analysis of a tire testing machine. Since the machine was designed to conduct different tire tests, different structural requirements of the tire positioning mechanism pertaining to each test were taken into consideration, and the structure was analyzed for maximum forces and moments acting on the assembly. Cleat testing subjects the tire as well as the structure to an impulse force which calls for the vibrational analysis of the assembly to avoid the structure from resonating. The design was modified to get it easily manufactured and assembled. These design changes and the aspects taken into consideration have also been discussed. / Master of Science

La force mentale est l'un des concepts les plus utilisés en psychologie du sport pour expliquer l'excellence. La force mentale est considérée comme une ressource psychologique qui permet aux athlètes d'améliorer ou de maintenir leurs performances lorsqu'ils sont sous pression. Depuis les deux dernières décennies, l'intérêt croissant pour la force mentale a engendré un grand nombre de définitions et de modèles. Cette diversité de perspectives a entraîné une certaine imprécision quant à ce qui la caractérise, si bien qu'aucun consensus n'a encore été établi. Un cadre conceptuel intégrateur et plus parcimonieux s'avère nécessaire pour l'avancement des connaissances dans ce secteur de recherche. Cette thèse de doctorat vise donc à offrir une meilleure compréhension de la force mentale dans le contexte sportif. Pour ce faire, deux articles scientifiques soutiennent cette démarche. L'Article 1 présente une recension critique de la littérature qui a pour but de documenter, analyser et synthétiser les travaux empiriques portant sur la définition de la force mentale dans le sport au cours des 20 dernières années. En s'appuyant sur la littérature existante, un nouveau modèle est proposé. L'Article 2 porte sur la validation de ce modèle dans le cadre de deux études menées auprès d'athlètes qui pratiquent une discipline sportive d'endurance. La première étude, réalisée à partir d'un devis corrélationnel, consiste à valider le modèle auprès de 649 coureurs de différents niveaux compétitifs (c.-à-d. novices à expérimentés). La seconde étude, de nature expérimentale, vise à appuyer les résultats de cette première étude en testant le modèle lors d'une épreuve cycliste in situ auprès de 74 athlètes expérimentés (c.-à-d. cyclistes). Les résultats de l'Article 1 ont permis de clarifier les enjeux conceptuels à propos de la nature de la force mentale, puis de regrouper les informations pour identifier ses composantes clés. Ces composantes ont servi à concevoir un nouveau modèle multidimensionnel, nommément le modèle Efficacité-Maîtrise de soi-Objectif (EMO). Selon le modèle EMO, la force mentale est définie à partir de trois ressources psychologiques, soit les objectifs ambitieux, la perception d'efficacité personnelle et la maîtrise de soi. Ces ressources agissent par quatre mécanismes psychologiques - attention, effort, persévérance, stratégies - lorsque les athlètes font face à un stresseur qui met en péril l'atteinte de leurs objectifs. Les résultats des deux études présentées dans l'Article 2 soutiennent le modèle EMO. Ils révèlent que les athlètes ayant des ressources élevées de force mentale avant une activité d'endurance seraient plus enclins à déployer leurs mécanismes pendant l'activité. Ainsi, ils atteindraient des niveaux de performance en lien avec les objectifs qu'ils se sont fixés au préalable. Cette thèse propose un cadre conceptuel mettant en lumière les ressources essentielles de la force mentale tout en expliquant son influence sur la performance dans des situations adverses. Cette recherche présente une nouvelle façon de définir, d'opérationnaliser et de valider la force mentale, ce qui mène à diverses considérations théoriques, méthodologiques et pratiques. Des pistes de recherche futures sont présentées, ainsi que des stratégies à l'intention des entraîneurs, des parents et des consultants en performance mentale pour soutenir les athlètes dans l'optimisation de leur force mentale. / Mental toughness has been recognized as among the most prevailing concepts in sports psychology to explain athletic performance. Mental toughness is considered a psychological resource that allows athletes to improve or maintain performance in challenging situations. Given its widespread interest over the past two decades, multiple models and definitions have been proposed. This diversity of perspectives has led to a certain confusion regarding its conceptualization, such that no consensus has been reached. Henceforth, a more parsimonious conceptual framework is needed to advance knowledge in this research domain. In this line, this doctoral dissertation intends to provide a better understanding of mental toughness in sport. Two scientific articles constitute this dissertation. Article 1 presents a critical review whose aims are to document, analyze, and synthesize empirical findings on the conceptualization of mental toughness in sport over the past 20 years. Based on this literature search, a new model is proposed. The purpose of Article 2 is to test this model in endurance sports within the confines of two studies. The first study (i.e., cross-sectional), consists of validating the model among 649 competitive runners of various levels (i.e., novice to experienced). The second study (i.e., experimental) aims to extend the results of the first study by testing the model during an in-situ sport-specific cycling performance with 74 trained athletes (i.e., cyclists). In Article 1, we critically addressed the conceptual ambiguities surrounding the nature of mental toughness and identified its most central components, based on existing models and definitions. These findings led to the elaboration of a new multidimensional framework, namely the Goal-Expectancy-Self-Control model (GES). The GES model posits that mental toughness is characterized by three psychological resources: challenging goals, self-efficacy, and self-control. According to this model, mental toughness ressources operate through four psychological mechanisms -- attention, effort, perseverance, strategies -- when athletes encounter a stressor that puts goal attainment at risk. The results of the two studies presented in Article 2 generally support the GES model. They reveal that athletes pursuing challenging goals, that perceive high self-control, and that feel highly confident before an endurance activity are more likely to deploy their four mechanisms during the activity. In turn, they achieve higher levels of performance, in line with their initial goals. This dissertation proposes a conceptual framework that highlights the most essential resources of mental toughness and explains their influence on performance in pressurized contexts. This research presents a new way of defining, operationalizing, and validating mental toughness, which has important theoretical, methodological, and practical implications. Future research directions are presented, as well as strategies for coaches, parents, and mental performance consultants to support athletes in optimizing their mental toughness.

<p>The first force and moment measurements were conducted in the BAM6QT. Three 7-degree half-angle sharp cones were tested, one with base radius of 4.5 in. and two with base radius of 3.5 in. made out of different materials. Models were tested at 0 and 2 degrees angle of attack. Models were tested over a range of burst pressures and Reynolds numbers. Models were fitted onto a strain gauge, 6 component, internal, moment balance. Multiple assemblies were tested that mounted the balance in the BAM6QT. High-speed schlieren video was used to monitor flow conditions and track the movement of the tunnel and model. Three entries were performed in the BAM6QT. The improvement in data quality with each new entry is shown and the startup and running loads from entry 3 are analyzed.</p> <p>Startup loads were measured and are of importance in determining the load range needed to operate in the BAM6QT. Large startup loads up to 40X the running load were identified. Tunnel movement was measured and was used to approximate the inertial loading during startup and the run. The inertial loading was not found to be the cause of the large startup loads. Schlieren video was used to qualitatively review the startup flow. It was found the large startup loads in axial force were plausibly from the high-pressure subsonic flow evacuating the nozzle. For normal force and pitching moment, the startup loads peak at a different time than axial force and appear to be from a shock-shock interaction nearby the model. Trends in startup load with changing model geometry, AoA, and burst pressure were put together to form an empirical estimation for startup loads sharp cones. </p> <p>Running loads were profiled and found to be trending with burst pressure and model geometry similarly to Newtonian flow theory predictions. However, due to the lack of a base pressure measurement, the results are uncorrected for sting effects and differ from Newtonian flow theory by a scalar. A 5.3 Hz oscillation in axial force was identified. The frequency of the oscillation is the same as the frequency of the quasi-steady flow periods caused by the reflection of the expansion fan in the driver tube. Normal force during the running load was found to be measuring positive loads when at 0 degrees angle of attack. Both the axial and normal force phenomena were unexpected and were investigated but both require further research. </p> <p><br></p> <p><br></p> <p><br></p> <p><br></p>

Early in the ship design process, naval architects must often evaluate and compare multiple hull forms for a specific set of requirements. Analytical tools are useful for quick comparisons, but they usually specialize in a specific hull type and are therefore not adequate for comparing dissimilar hull types. Scale model hydrodynamic testing is the traditional evaluation method, and is applicable to most hull forms. Scale model tests are usually performed on the largest model possible in order to achieve the most accurate performance predictions. However, such testing is very resource intensive, and is therefore not a cost effective method of evaluating multiple hull forms. This thesis explores the testing of small scale models. It is hypothesized that although the data acquired by these tests will not be accurate enough for performance predictions, they will be accurate enough to rank the performance of the multiple hull forms being evaluated.

Diploma thesis is focused on structural assessment and strengthening of the reinforced concrete flor slab disturbed by excessive deflection. Thesis included assesment of the existing construction and design method of strengthening of the floor structure with system using prestressing strands without bond.