Ideas for ways to use textiles and other materials as body coverings, or as a form of apparel decoration, as well as protection, continued to evolve throughout history. More complex ideas and outcomes developed with the advent of weaving, and rectangular shapes were draped in folds, tied, or wrapped around the body. An accepted practice in the apparel industry is seeking inspiration for ideas from a variety of people, places, and things. This practice of seeking inspiration from the environment leads to the question of whether copying is inherent within the apparel industry. History of costume research and study indicate that it is generally accepted that people wear differing apparel for each season of the year, with some repeat, or copying, in the same season in subsequent years. The terms counterfeiting, knocking-off, and copying are often used interchangeably, but further exploration of the terms show they are not the same. Counterfeiting has become, and remains a hot topic in the apparel industry, particularly in product development. Some designers have begun to challenge and demand their work be protected in some manner such as copyrights, trademarks, or patents. Questions and concerns abound among product developers. This study was exploratory in nature, seeking a definition, and identifying a specific point in the product development process, when a certain activity (i.e., copying) is more likely to be performed. Therefore, qualitative methods were used to achieve the objectives of the research. This research took a cross-sectional approach within a qualitative design study when selecting the participants. The cross-sections for the participants of this study were those participants in positions of direct influence on apparel product development. Analyzing the perceptions of the participants from the cross-sections in detail, inferences were made about the industry definition and method of copying, time of occurrence, and those most likely involved in decision making. The instrument for the study was an online survey with open-ended questions and fixed-response questions. Of the 20 participants, 11 accessed the survey with 10 choosing to participate. While some degree of similarity was observed in several of the definitions of copying, such as taking existing products to create new products, there was distinction when participants used phrases such as copying 'without changing anything' to 'copying the idea and concept.' Participants' definition of knocking-off can be summarized as a copy with variation in price point. Participants noted that the process of counterfeiting was an unauthorized or illegal copy of a product and often included copying labels or logos. Key reasons for copying products were reported as following trends and speed to market. / Ph. D.

Lors de la phase de certification d’un turbomoteur, le motoriste doit démontrer que la perte d’une pale de rotor ne conduit pas au "Knocking-Off", c’est à dire à la rupture en cascade des pales suiveuses. Cette démonstration est faite en général par un essai au banc coûteux car partiellement destructif. Grâce à l’amélioration des moyens de calcul, il devient possible de simuler la réponse transitoire de la structure soumise à ce type de chargement très complexe. En tant que point d’entrée sur la simulation, la connaissance du comportement des matériaux est primordiale. Or, peu d’études sont publiées sur le comportement dynamique des superalliages à base nickel monocristallins et, de surcroît, à des températures élevées de l’ordre de 1000°C. Pour prédire efficacement les conséquences d’impacts sur des pales de turbines, des travaux expérimentaux et numériques ont été réalisés sur un monocristal couramment utilisé par Turbomeca. Des essais de compression dynamique à haute température sur barres de Hopkinson permettent d’estimer le seuil de plasticité et l’écrouissage du matériau en fonction de l’orientation du cristal, de la vitesse de déformation et de la température. Les paramètres d’une loi visco-plastique anisotrope sont identifiés pour modéliser efficacement le comportement macroscopique du MC2 sous des chargements intenses et fortement multi-axiaux. Une campagne d’essais balistiques au banc de Safran Snecma a été réalisée sur des plaques et des pales monocristallines à hautes températures. Afin de prendre en compte la fragmentation des profils dans les calculs de perte de pale, un critère en déformation plastique dépendante du taux de triaxialité des contraintes est calibré puis validé par confrontation aux essais de tirs sur plaques. Des mesures de stéréo-corrélation postmortem et des enregistrements à la caméra rapide permettent de valider les simulations. Une pratique de modélisation de la perte d’une pale avec l’outil LS-Dyna a été établie et appliquée à un cas industriel de perte de pale en service. Enfin, en vue de justifier le découplage temporel entre les dommages primaires, liés aux impacts directs sur les premières pales suiveuses, et secondaires, liés aux effets de l’excentration, une approche de dynamique d’ensemble de ligne d’arbre a été développée puis validée. / During the certification process of a turbo engine, the engine manufacturer has to demonstrate that the loss of a rotor blade does not lead to the "knocking-off" phenomenon, in other words to the cascading failure of the successive blades. Generally, this demonstration is carried out through a costly rig test driving to the partial destruction of the engine. Thanks to the improvement of computational resources, it is now possible to simulate the transient response of the structure subjected to this complex loading. The knowledge of material behavior turns out to be the essential starting point for the simulation. However, only a few studies have been published on the dynamic behavior of nickel-based single crystal superalloys at high temperature reaching 1000°C. With a view to efficiently predicting the consequences of impacts on turbine blades, experimental and numerical works have been conducted on a single crystal frequently used by Turbomeca. High-temperature dynamic compressive tests on Split Hopkinson Pressure Bars (SHPB) have enabled to estimate the material plasticity level and hardening, depending on the crystal orientation, strain rate and temperature. The parameters of a viscoplastic anisotropic law have been identified to effectively model the MC2 macroscopic behavior under highly intense and multiaxial loading. At Safran Snecma Villaroche, ballistic tests have been undertaken on both single crystal plates and blades under high temperatures. In order to consider the fragmentation of profiles in blade-off simulations, a plastic strain criterion depending on stress triaxiality has been calibrated and validated by comparison with the impacts on blades. Post-mortem digital images correlation measurements and high-speed camera recordings have confirmed these simulations. Using LS-Dyna solver, a blade-off modeling strategy has been created and applied to an actual blade-off industrial case. Finally, a rotordynamics approach has been developed and validated with the aim of separately analyzing the primary damage, caused by direct impacts on the first following blades, and the secondary damage due to the effects of unbalance on a flexible rotor.