[pt] Esta dissertação tem por objetivo realizar a caracterização metrológica de scanners ópticos tridimensionais por projeção de luz estruturada com vistas à aplicação em ensaios de coletes balísticos. Técnicas de digitalização tridimensional vêm ganhando popularidade nas últimas décadas, entretanto o recente emprego de equipamentos de digitalização 3D em ensaios de coletes balísticos constitui uma nova aplicação para estes equipamentos, em especial na caracterização dos traumas originados pelos impactos de projéteis, o que motivou a realização do estudo. A metodologia empregada fundamentou-se nas pesquisas bibliográfica, documental, experimental e de laboratório que tiveram por objetivo coletar dados utilizando scanner por projeção de luz estruturada no contexto de ensaios de coletes balísticos e compará-los com valores de referência. Foram sugeridos processos de alinhamento, segmentação, filtragem e estabelecimento de planos de referência que se mostraram adequados ao tratamento das nuvens de pontos obtidas nos ensaios de coletes balísticos. Os resultados confirmaram os erros sistemáticos relatados na literatura para equipamentos de digitalização por luz estruturada e possibilitaram uma estimativa da incerteza de medição para o equipamento em questão. Concluiuse que os valores críticos de medição de traumas são corretamente medidos pelo instrumento de digitalização 3D e por meio da utilização do método sugerido para tratamento de nuvens de pontos neste contexto. / [en] This dissertation aims at performing the metrological characterization of three-dimensional optical scanners by structured light projection for application in ballistic vest tests. Three-dimensional scanning techniques have been gaining popularity in recent decades, however the recent use of 3D scanning equipment in ballistic vests testing is a new application for these devices, especially in the characterization of traumas caused by projectile impacts, which motivated the realization of the study. The methodology used was based on bibliographic, documentary, experimental and laboratory research aimed at collecting data using a structured light projection scanner in the context of ballistic vests tests and comparing them with reference values. Procedures for alignment, segmentation, filtering and establishment of reference planes were suggested, which proved to be adequate for the treatment of point clouds obtained from ballistic vest tests. The results confirmed the systematic errors reported in the literature for structured light scanning equipment and made it possible to estimate the measurement uncertainty for the equipment in question. It was concluded that the critical trauma measurement values are correctly measured by the 3D scanning instrument and by using the suggested method for treating point clouds in this context.

Ce manuscrit de thèse porte sur l’élaboration de nouveaux matériaux pour la protection balistique grâce à l’apport du procédé de frittage flash. Il s’agit, en effet, d’associer deux composés possédant des températures de frittage éloignées, tels que l’alumine et l’aluminium, matériaux de référence utilisés dans la protection balistique.La première voie testée était un assemblage bi-matériau, réalisé par frittage d’une poudre d’aluminium sur un plot d’alumine préalablement fritté. Cette étude a permis d’observer la formation de la liaison alumine/aluminium par microscopie électronique à balayage et en transmission et d’optimiser les paramètres d’assemblage pour l’obtention d’un bi-matériau possédant une forte cohésion interfaciale. Des outils de caractérisation adaptés (diffraction des rayons X et indentation Vickers) ont mis en évidence des contraintes résiduelles dans la céramique qui résultent de la différence de coefficients de dilatation thermique entre les deux composés lors du refroidissement du bi-matériau. Ces assemblages ont également fait l’objet d’essais statiques (essais de traction indirects) et d’essais dynamiques (tirs balistiques). Ces essais ont démontré la très grandec ohésion des assemblages et ont permis de valider la pertinence de l’étude de matériaux de protection balistique par des essais statiques, qui sont plus faciles à mettre en oeuvre.L’autre voie envisagée était de fritter en une seule étape un matériau à gradient de composition, de l’alumine pure à l'aluminium pur avec une interphase constituée de mélanges alumine/aluminium. D’un point de vue technique, le frittage flash a démontré sa capacité à générer un gradient de température de plusieurs centaines de degrés à l’intérieur d’un échantillon de quelques millimètres de haut, grâce à l'utilisation d'un moulede forme spécifique. Malheureusement, la mauvaise mouillabilité de l’alumine par l’aluminium n’a pas permis d’abaisser la température de frittage des mélanges alumine/aluminium par rapport à l’alumine pure. Elle a au contraire conduit à augmenter la température de frittage des mélanges de ~200 °C, empêchant l’élaboration du matériau à gradient de composition. Cette voie a tout de même permis l’élaboration de composites denses (>99 %) à matrice d'alumine avec de faibles quantités d'aluminium, de l'ordre de 5 % en masse. / This dissertation describes the synthesis of new components for ballistic protection with the assistance of flash sintering. Indeed, the objective is to associate two compounds showing very different sintering temperatures – such as alumina and aluminum, two reference materials for ballistic protection applications.The first synthesis method tested was the elaboration of a bi-material via the sintering of aluminump owder on alumina bulks. This study permitted to observe the formation of the alumina/aluminum bonding by scanning and transmission electron microscopy and to optimize the assembly parameters in order to obtain a bimaterials howing a strong interfacial cohesion. Adapted characterization techniques (X-rays diffraction and Vickers indentation) revealed residual stresses inside the ceramic that stemmed from the difference of thermal expansion coefficients between the two compounds during the cooling of the bi-material. Moreover, these assemblies have been tested with static (indirect tensile) tests and dynamic (ballistic) tests. These tests evincedthe very strong cohesion of the assemblies and permitted to confirm the relevance of static tests, which are easierto set up, for the evaluation of materials for ballistic protection.The other synthesis method considered was the one step sintering of a material displaying a gradient of composition, from pure alumina to pure aluminum with an interphase constituted by alumina/aluminum combinations. From a technical point of view, the flash sintering process proved capable of generating a thermal gradient of several hundreds of degrees inside a sample a few millimeters high, thanks to the use of a specific shape die. Unfortunately, the limited wetting of alumina by aluminum prevents the sintering of the alumina/aluminum mixtures from temperatures being lower than that of pure alumina. On the contrary, this limited wetting leads to an increase in the sintering temperature of the composites of ~200 °C and prevents the preparation of a material showing a composition gradient. Nevertheless, this method permits the synthesis of dense alumina composites (<99 %) containing ~5 wt.% aluminum.