Materials have typically been selected based on the familiarities and past experiences of a limited number of designers with a limited number of materials. Problems arise when the designer is unfamiliar with new or improved materials, or production processes more efficient and economical than past choices. Proper utilization of complete materials and processing information would require acquisition, understanding, and manipulation of huge amounts of data, including dependencies among variables and "what-if" situations. The problem of materials selection has been addressed with a variety of techniques, from simple broad-based heuristics as guidelines for selection, to elaborate expert system technologies for specific selection situations. However, most materials selection methodologies concentrate only on material properties, leaving other decision criteria with secondary importance. Factors such as component service environment, design features, and feasible manufacturing methods directly influence the material choice, but are seldom addressed in systematic materials selection procedures. This research addresses the problem of developing a systematic materials selection procedure that can be integrated with standard materials data bases. The three-phase methodology developed utilizes a group technology code and cluster analysis method for the selection. The first phase is of go/no go nature, and utilizes the possible service environment requirements of ferromagnetism and chemical corrosion resistance to eliminate materials from candidacy. In the second phase, a cluster analysis is performed on key design and manufacturing attributes captured in a group technology code for remaining materials. The final phase of the methodology is user-driven, in which further analysis of the output of the cluster analysis can be performed for more specific or subjective attributes. / Master of Science

Pour rendre les véhicules électriques plus attractifs, les recherches actuelles se portent sur l'augmentation de l'autonomie de la batterie. Deux méthodes existent pour le réaliser : travailler sur les technologies de batterie ou alléger le véhicule. Une voie classique d'allègement est de remplacer les matériaux des pièces existantes par d'autres matériaux plus légers. Dans le cas des alliages d'aluminium, les matériaux de remplacement possibles sont les polymères ou les alliages de magnésium. Dans cette étude, l'alliage de magnésium commercial AZ91 a été modifié par ajout d'éléments d'alliages supplémentaires. Des échantillons d'alliages modifiés coulés sable ont été étudiés pour en comparer la microstructure et les comportements mécaniques et face à la corrosion. Des observations de coupes métallographiques avec analyse quantitative d'image ont été couplées avec de la microanalyse X , de la diffraction des rayons X et avec de l'analyse thermique , pour analyser les changements de microstructure et de séquence de précipitation dues aux ajouts. La réponse aux traitements thermiques a aussi été quantifiée. Des essais mécaniques ont été réalisés pour classer les différents alliages de magnésium selon leurs performances. Enfin, l'AZ91D est connu pour son bon comportement en corrosion par rapport aux autres alliages de magnésium. L'influence des ajouts d'éléments sur la performance en corrosion a également été étudiée par des méthodes conventionnelles d'électrochimie et par des essais industriels. / To make electric vehicles more attractive, researches to increase the autonomy of electric vehicles are underway on the battery technology and on the lightening of many vehicle parts. For the second approach, one way is to replace aluminum by magnesium without loosing mechanical and corrosion resistance performance. The AZ91 commercial alloy was modified with additional elements to meet the mechanical requirements for the power electronic casings. Sand casting samples were studied for the comparison of microstructure and properties. First, metallographic observations were performed with an optical microscope and a SEM combined with microanalysis (epma) coupled with quantitative image analysis, then the solidification sequence was analysed using thermal analysis in order to identify the changes in microstructure when alloying. Combined with DTA, X-ray diffraction and micro probe analysis, these techniques are useful to understand the solidification sequence of the complex alloys and their response to heat treatments. Tensile and hardness tests were then performed in order to quantify the mechanical strength of the different samples. Fractographic observations were also done to characterize the rupture of the specimens. AZ91D is known for its good corrosion resistance. Corrosion behaviour of modified alloys was assessed by electrochemical and non-electrochemical methods.

Cette thèse suit une démarche « materials-by-design » avec pour objectif le développement d'une méthode de conception dédiée aux panneaux sandwichs architecturés pour l'obtention de propriétés multifonctionnelles. Cette méthode s'appuie sur l'utilisation d'un algorithme génétique permettant simultanément une sélection de matériaux (variables discrètes) et un pré-dimensionnement du panneau (variables continues). Trois architectures de cœur ont été étudiées : les mousses, les nids-d'abeilles hexagonaux et les treillis tétraédriques. Dans cette thèse, on définit deux approches différentes de sélection des matériaux. Dans un premier temps, les matériaux architecturés sont considérés comme des matériaux existants, dont les propriétés sont référencées dans une base de données fermée. Cette approche est appelée optimisation par « voie réelle ». Afin d'ouvrir les possibilités en termes de sélection de matériaux, la deuxième approche considère une description semi-continue des matériaux architecturés et est appelée optimisation par « voie virtuelle ». Le matériau cœur est décrit par un matériau constitutif (variable discrète) et par une ou plusieurs variables géométriques continues représentant l'architecture. Utilisant ces deux approches, différentes propriétés d'emploi des panneaux sandwichs sont évaluées : rigidité et résistance en flexion, atténuation acoustique, résistance et isolation thermique, et enfin résistance aux chocs impulsionnels. Chaque fonction est optimisée à masse minimale par optimisation bi-objectifs. Différents cas d'optimisation tri-objectifs sont également présentés afin d'évaluer la compatibilité entre propriétés. En effet, la forme de la surface de compromis obtenue donne une indication sur la compatibilité entre les différents critères. Cette étape d'optimisation permet également l'identification des paramètres de conception optimaux. Dans le cas d'une optimisation par « voie virtuelle », une comparaison directe entre architectures est aussi possible. Cependant, la démarche d'optimisation mise en place est complexe car globale et travaillant avec des variables mixtes. Deux méthodes mixtes, couplant l'algorithme génétique avec d'autres approches, sont proposées pour permettre un accroissement de la complexité de l'analyse tout en garantissant une complexité raisonnable de l'optimisation. / The present thesis aims at developing a design method dedicated to the optimization of architectured sandwich panels for multifunctional properties following a “materials-by-design” approach. This method is based on a genetic algorithm which enables to deal with materials selection (discrete variables) and geometrical dimensioning (continuous variables) simultaneously. Three core architectures have been investigated: foams, hexagonal honeycombs and tetrahedral truss structures. In this thesis, two main paths for material selection are defined. In the first one, architectured materials are considered as existing materials with properties referenced in a closed materials database. This is called the “real path” optimization. In order to expand the range of possibilities in terms of materials selection, a semi-continuous description of the architectured materials is considered in the second path, which is called “virtual path” optimization. The core material is described by a constitutive material (discrete variable) and a set of continuous geometrical variables representing the architecture. Using these two aforementioned approaches, several working properties of sandwich panels have been evaluated: flexural stiffness and strength, acoustic damping, thermal resistance and insulation, and finally blast mitigation. Bi-objective optimizations were performed in order to optimize each property in a minimal weight design. Some tri-objective cases are also presented, thus assessing the compatibility between different specifications. Indeed, this is achieved by relating trade-off surface shape to the compatibility between specifications. The optimization results also help identify the optimal design regarding the different criteria. Using the “virtual path” approach, a direct comparison between the different core architectures is achievable. Nevertheless, by being global and dealing with mixed variables, the obtained optimization process is complex. Two mixed methods where genetic algorithm is coupled with other approaches are proposed in order to increase the analysis complexity while providing a reasonable optimization complexity.

Flexible foams have unique properties that make them well-suited to several engineering systems. They are often used in impact-related applications because of their superior energy absorption performance. Many multifunctional materials are also derived from flexible foams due to their high customizability, which allows them to satisfy a wide range of performance requirements. Though flexible foams have high potential in these and other classes of material applications, their success relies on the proper characterization of their complex behavior. This thesis promotes the application of flexible foams by characterizing their electromechanical response through both experimental and theoretical approaches. One study in this thesis theoretically determines material indices that minimize a foam's mass and cost while meeting particular energy absorption requirements. These novel indices are combined with a common Ashby approach to facilitate materials selection of energy-absorbing foam components. Another study uses a particular multifunctional nanocomposite foam to experimentally determine deviations in its voltage response while under a cyclic impacting regime; specifically, factors of transient effects, environmental conditions (humidity and temperature), and permanent material degradation are investigated. Results presented in this thesis promote the application of flexible foams to various forms of impact-absorbing sports equipment (specifically football helmet pads and gait-sensing shoe insoles), but are also useful in various other engineering designs.

Metal on metal wear at high sliding speeds and high contact pressures results in the melting of one or both of the sliding solid bodies due to heat generated at the contact interface. Understanding the influence of sliding speeds, contact pressures and material properties on wear rates is important in developing predictive models for designing more efficient and effective engineering system components. Typical engineering applications subjected to these extreme conditions include ultrahigh speed machining, rocket sleds, large caliber cannon, and electromagnetic launchers. Sliding speeds on the order of 1,000 m/s and contact pressures in excess of 100 MPa are common in these applications and difficult to replicate in a laboratory environment. A unique wedge experiment using a minor caliber electromagnetic launcher has been developed and implemented to characterize wear deposition of a 6061-T6 aluminum sliding body on several different guider materials of varying mechanical and thermal properties at sliding speeds from 0 – 1,200 m/s and contact pressures from 100 – 225 MPa. Optical microscopy and 3D profilometry were used to characterize and quantify the slider wear. Three distinct wear regions, plasticity dominated, severe plastic deformation and melt lubrication were observed. Test results provided evidence that the aluminum slider contact interface was molten. Modeling of the experimental wear data showed a dependence on pressure and velocity and guider material properties, density and specific heat. A predictive wear model was developed for the melt lubrication region as a tool for designing components subjected to similar operating conditions.

O presente estudo trata de temas relacionados à seleção de materiais e ao design de produto frente às questões ambientais. Percebe-se atualmente a tendência de desenvolvimento de produtos insustentáveis, como é o caso dos multi-materiais. Apesar das vantagens técnicas, esses produtos são causadores de impactos ambientais negativos, já que apresentam dificuldades de reciclagem, decorrentes da complexidade na separação dos seus materiais. Na presente pesquisa discute-se, através de revisão bibliográfica e de estudos práticos, a necessidade de desenvolvimento de soluções a curto prazo para esse problema. O objetivo consiste em estudar a reciclagem de produtos multi-materiais, sem separação prévia, visando a utilização do material resultante em novas aplicações com valor agregado. O estudo divide-se em: (I) Revisão Bibliográfica, (II) Estudo Prático A e (III) Estudo Prático B. Na revisão bibliográfica apresenta-se o contexto teórico e científico a respeito dos temas centrais para posterior discussão dos resultados obtidos nas etapas práticas. O Estudo Prático A envolve a reciclagem de escovas de dente multi-materiais através de micronização. Posteriormente o material resultante foi caracterizado por microscopia eletrônica de varredura (MEV), teste de densidade, ensaio de tração e análise térmica dinâmico-mecânico (DMA). Apresentou-se ainda a seleção de potenciais áreas de aplicação para o novo material reciclado, por meio de Mapas de Propriedades de Materiais e teste de viabilidade da aplicação selecionada. No Estudo Prático B utilizam-se duas amostras com granulometrias distintas, para avaliar a influência do tamanho das partículas do material reciclado. Na etapa de caracterização, além dos ensaios conduzidos no Estudo A, realizou-se ainda distribuição granulométrica, ensaio de dureza, calorimetria exploratória diferencial (DSC) e análise termogravimétrica (TGA). Os resultados demonstraram a viabilidade técnica de se promover a reciclagem de escovas de dente multi-materiais por meio do processo de reciclagem mecânica tradicional sem separação prévia. O material reciclado apresentou potencial para ser utilizado na fabricação de laminado sintético para produção de calçados e componentes. Na avaliação da influência do tamanho das partículas, constatou-se que não houve influência significativa no material resultante. Destaca-se ainda como contribuição e tecnológica deste estudo a proposição de uma alternativa tecnicamente viável para a reciclagem de produtos teoricamente “não-recicláveis”, contribuindo com a redução da geração de resíduos sólidos. / This study deals with issues related to product design and material selection, facing the environmental issues. Developments in design and materials usage unleashed the tendency of developing unsustainable products, as the multi-materials. These products cause severe negative environmental impacts, since its recycling is difficulted by the complexity in separating the materials. In this context, it is argued, through literature review and practical studies, the need of developing short-term solutions to this problem. The objective is to study multi-material products recycling, without previous sorting, aiming the use of the resulting material in applications with added value. The research is divided in three parts: (I) Bibliographic Review, (II) Practical Study A and (III) Practical Study B. Bibliographic Review presents the scientific and theoretic context regarding the central themes for later discussion of the results obtained in the practical parts. Practical Study A involves the reprocessing of multi-material toothbrushes through micronization. Subsequently, the resulting material is characterized by scanning electron microscopy (SEM), density test, tensile test and dynamic mechanical analysis (DMA). It is also presented the selection of potential areas of application for the new recycled material through Materials Properties Charts and a viability test of the selected application. In Practical Study B, two samples of different particle sizes were used to evaluate the influence of the recycled material’s particle sizes. In the characterization stage, in addition to the tests conducted in Study A, granulometric distribution, hardness test, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were also performed. The results demonstrated the technical feasibility of reprocessing multi-material toothbrushes through the traditional mechanical recycling process, without previous sorting. The recycled material presented potential for application in synthetic laminates for shoes and components production. Regarding the particles size influence, it was found that there was no significant influence in the resulted material. There is also the technological contribution which is the proposition of an alternative for the recycling of theoretically "non-recyclable" products, contributing to the reduction of solid waste generation.

As ferramentas computacionais utilizadas em diferentes áreas de pesquisa têm como vantagem sobre análises e ensaios reais a possibilidade de analisar sistemas em diferentes condições de forma mais ágil e com menor consumo de tempo e recursos. A modelagem óptica de dispositivos fotovoltaicos é bastante difundida. Existem diferentes trabalhos na área, com diferentes escopos e graus de detalhamento, que permitem a análise e melhor compreensão das diferentes etapas da conversão da radiação em energia elétrica, expandindo as possibilidades de otimização. No presente trabalho foi desenvolvida, em uma etapa inicial, uma metodologia computacional para análise óptica de módulos fotovoltaicos, para então, em uma segunda etapa, serem realizados estudos do desempenho de diferentes materiais inseridos no conjunto de camadas que compõe os módulos, através da metodologia. O modelo óptico que embasa o método tem como foco os módulos de silício monocristalino. Esses módulos agregam de três a quatro camadas transparentes sobre as células fotovoltaicas. Ao incidir nesse conjunto de camadas radiação é submetida a diferentes eventos de extinção, como função do comprimento de onda da radiação e ângulo de incidência, que devem ser previstos em um modelo de forma a obter-se resultados válidos de transmissividade. A metodologia propõe a realização de uma análise aprofundada dos fenômenos ópticos que ocorrem mediante a incidência de radiação em um módulo fotovoltaico de modo a auxiliar na análise da adequação e desempenho de diferentes materiais ao sistema óptico formado. A otimização da transmissão de radiação em um módulo fotovoltaico tem uma influência direta e significativa sobre a eficiência de tais dispositivos, justificando sua importância. A validação do modelo foi realizada através da literatura, em partes, e apresentou coerência com os resultados de referência. Foram produzidos na segunda etapa estudos de desempenho de materiais ou propriedades isoladamente. No primeiro estudo foram analisados três materiais para aplicação como filme de passivação sobre a célula, sendo eles Si3N4, SiO2, e TiO2; o filme de Si3N4 apresentou o melhor desempenho. O segundo estudo, de avaliação da influência do índice de refração do encapsulante na transmissividade do sistema, demonstrou que a variação desse parâmetro tem muito pouca influência. No terceiro estudo foi analisado o potencial dos materiais PDMS e TiO2 como filmes anti-reflexo sobre vidro. O PDMS gerou melhores resultados de transmissividade. Por fim um estudo de desempenho de um conjunto de materiais frente à mudança do espectro incidente foi realizado. Foi utilizado até então o espectro de referência, que foi então comparado a um espectro médio de um dia de equinócio da cidade de Porto Alegre. O desempenho do sistema foi em torno de 3% inferior em incidência normal. / Computational tools raise the possibility of studying and understanding systems under different conditions in a faster and less resource and time consuming way. The optical modeling of photovoltaic devices is a very developed issue, and paperworks and projects in different scopes e levels of detail were produced, providing a better understanding of the different steps of converting light into electricity, expanding optimization possibilities. For this project a computational methodology was developed, as an initial step, for the optical assessment of the transmission of radiation in photovoltaic modules. In a second step, studies were performed using the method as a tool for analyzing the system formed by the layers covering the cells embedded in modules. The optical model describes monocristalline silicon modules, which are constituted by three to four layers covering the cell. Once it penetrates the set of layers, incident light suffers different extinction phenomena, which are predicted in this model in order to generate valid results. It’s a function of wavelength and incidence angle of the incoming radiation. The model presented aims to deeply analyse and understand the optical phenomena light undergoes through its way from the external environment to the interior of the cell, supporting the process of observing the performance and adequacy of different materials as the referred layers. Optimizing transmission of radiation in a photovoltaic device plays a main role in increasing the efficiency of the energy conversion process, which is why it’s so important. The model was validated by literature in parts, and showed coherence within reference results. Studies were produced in a second step of this work, using the method, concerning optical issues, for the thin film on top of the cell, the refractive index of the encapsulating material, and the optical effect of coating the outer glass surface. In the first study Si3N4, SiO2 and TiO2 were analyzed; the Si3N4 film produced the best results. The second study, concerning encapsulant’s refractive index, demonstrates this parameter has a very weak influence in the system’s transmission. The third one observed the performance of two materials, PDMS and TiO2, as AR coating,. The PDMS film produced a better effect. At last, the best performance set of layers was analyzed under a representative spectral distribution of an equinox day of the city of Porto Alegre, considering so far it was used the standard. The transmission suffered a slight decrease, around 3%.

Les méthodes de sélection de matériaux monolithiques peuvent conduire à des impasses lorsque les exigences fonctionnelles sont très élevées ou contradictoires. Le passage aux multimatériaux peut alors être envisagé. L’objectif de la thèse est de proposer une méthode de conception de multimatériaux à architecture fixée, avec en perspective une application à la conception de conduites offshore pour le génie pétrolier. Seuls les multimatériaux à architecture multicouche sont considérés et la méthode de conception est redéfinie comme une méthode de sélection des constituants du multimatériau et de dimensionnement. Une adaptation des étapes classiques de sélection des matériaux conduit à présenter la méthode en détail sur des exemples simples. Les techniques de programmation par satisfaction de contraintes s’avèrent nécessaires pour la résolution de cas réels de conception multimatériaux. L’application à la conception de conduites offshore permet de valider la méthode et de démontrer sa pertinence. / When the design requirements are either too stringent or are conflicting, no monolithic material solution exists. In such cases the selection of a multimaterial could be considered. The primary aim of this thesis is to provide a methodology for designing multi-materials with a prescribed arrangement of the constituent materials. The second objective is to apply this new methodology to the design of a submarine pipeline. From amongst the huge variety of multi-material arrangements available, this study focusses on multilayered stackings and therefore the design methodology becomes a method for selecting the materials of the stack and sizing the layers. This original approach is presented in detail using basic examples in order to match the steps of classical methods for selecting engineering materials. The constraints programming techniques were very useful for solving real multimaterial design problems. Applying this new method to the design of a submarine pipeline permits its validation and provides proof of its relevance.

O interior automotivo, um produto que atualmente faz parte da vida da grande maioria dos habitantes do planeta, é projetado para favorecer a percepção de conforto, luxo, domínio e emoções agradáveis. No entanto deve-se questionar se é possível que os materiais aplicados nesses ambientes, como tecidos poliméricos, couro, espumas, vidros, podem influenciar o bem-estar dos passageiros do automóvel. Desta forma, a presente pesquisa visa avaliar, com o olhar do design para o bem-estar associado ao design de produto, quais as noções subjetivas de conforto, desconforto, emoções e bem-estar próprios das interações das pessoas com os materiais e componentes dos interiores automotivos. Para isso foram aplicados questionários qualitativos e quantitativos com um grupo de 200 estudantes universitários de engenharia, psicologia e design da cidade de Porto Alegre. Ainda foram medidas as distribuições de temperatura e pressão existentes na interface de um assento automotivo durante sua posição sentada, com o auxílio de sensores de medição de pressão e um termovisor infravermelho a fim de verificar a relação desses dados com as respostas obtidas nos questionários. Os participantes dessa pesquisa julgaram os interiores dos veículos populares como sendo limpos, de boa aparência, luxuosos e fáceis de dirigir, contribuindo para sua percepção de conforto. Por outro lado, foi observado um desconforto leve e baixa pressão no contato do corpo com os assentos. As emoções vividas nesses habitáculos foram consideradas como mais agradáveis do que desagradáveis, contudo os ocupantes dos veículos não acreditavam que isso contribuía para o seu bem-estar, mesmo quando julgaram suas vidas de moderadamente a muito satisfatórias durante a realização da pesquisa. Concluiu-se com os dados levantados, que o projeto de interiores de veículos populares apenas favorece o conforto, reduz o desconforto e contribui para emoções agradáveis porém não necessariamente, colabora para o bem-estar de seus ocupantes. Assim, para auxiliar os designers de ambientes reduzidos, foi sugerida uma proposta metodológica, como ferramenta de aplicação e avaliação em projeto das variáveis relacionadas ao conforto, desconforto, emoções e bem-estar. / The automotive interior, a product that is currently part of the life of the great majority of the inhabitants of the planet, is designed to foster the perception of comfort, luxury, domain and pleasant emotions. However one must question whether it is possible that the materials used in these environments, such as polymeric fabrics, leather, foam and glass can influence the well-being of drivers and passengers of these cars. Thus, this research aims to evaluate, with the look of the design for well-being associated with product design, which are subjective notions of comfort, discomfort, emotions and well-being of people during their own interactions with materials and components used in automotive interiors. With this aim, it was applied qualitative and quantitative questionnaires with a group of 200 university students from engineering, psychology and design of the city of Porto Alegre. Even it was measured pressure and temperature distributions existing at the interface of an automotive seat during the seated position with the aid of pressure measurement sensors and infrared imager in order to investigate the relationship of these data with the responses from the questionnaires. It was concluded that the participants of this study judged the interior of popular vehicles as clean, good-looking, luxurious, easy to drive, contributing to their perception of comfort. On the other hand, there was a mild discomfort and low pressure body contact with the seats. The emotions experienced in these cases were considered more pleasant than unpleasant, but the occupants did not believe that this contributed to their well-being, even when they thought their lives as moderately to very satisfactory during the research. It was concluded with the data collected that, the interior design of popular vehicles only favours comfort, reduces discomfort and contributes to pleasant emotions but not necessarily contributes to the well-being of its occupants. Therefore, to help designers of reduced environments, a methodology has been suggested as a tool for implementation and evaluation of design variables related to comfort, discomfort, emotions and well - being.

O presente estudo trata de temas relacionados à seleção de materiais e ao design de produto frente às questões ambientais. Percebe-se atualmente a tendência de desenvolvimento de produtos insustentáveis, como é o caso dos multi-materiais. Apesar das vantagens técnicas, esses produtos são causadores de impactos ambientais negativos, já que apresentam dificuldades de reciclagem, decorrentes da complexidade na separação dos seus materiais. Na presente pesquisa discute-se, através de revisão bibliográfica e de estudos práticos, a necessidade de desenvolvimento de soluções a curto prazo para esse problema. O objetivo consiste em estudar a reciclagem de produtos multi-materiais, sem separação prévia, visando a utilização do material resultante em novas aplicações com valor agregado. O estudo divide-se em: (I) Revisão Bibliográfica, (II) Estudo Prático A e (III) Estudo Prático B. Na revisão bibliográfica apresenta-se o contexto teórico e científico a respeito dos temas centrais para posterior discussão dos resultados obtidos nas etapas práticas. O Estudo Prático A envolve a reciclagem de escovas de dente multi-materiais através de micronização. Posteriormente o material resultante foi caracterizado por microscopia eletrônica de varredura (MEV), teste de densidade, ensaio de tração e análise térmica dinâmico-mecânico (DMA). Apresentou-se ainda a seleção de potenciais áreas de aplicação para o novo material reciclado, por meio de Mapas de Propriedades de Materiais e teste de viabilidade da aplicação selecionada. No Estudo Prático B utilizam-se duas amostras com granulometrias distintas, para avaliar a influência do tamanho das partículas do material reciclado. Na etapa de caracterização, além dos ensaios conduzidos no Estudo A, realizou-se ainda distribuição granulométrica, ensaio de dureza, calorimetria exploratória diferencial (DSC) e análise termogravimétrica (TGA). Os resultados demonstraram a viabilidade técnica de se promover a reciclagem de escovas de dente multi-materiais por meio do processo de reciclagem mecânica tradicional sem separação prévia. O material reciclado apresentou potencial para ser utilizado na fabricação de laminado sintético para produção de calçados e componentes. Na avaliação da influência do tamanho das partículas, constatou-se que não houve influência significativa no material resultante. Destaca-se ainda como contribuição e tecnológica deste estudo a proposição de uma alternativa tecnicamente viável para a reciclagem de produtos teoricamente “não-recicláveis”, contribuindo com a redução da geração de resíduos sólidos. / This study deals with issues related to product design and material selection, facing the environmental issues. Developments in design and materials usage unleashed the tendency of developing unsustainable products, as the multi-materials. These products cause severe negative environmental impacts, since its recycling is difficulted by the complexity in separating the materials. In this context, it is argued, through literature review and practical studies, the need of developing short-term solutions to this problem. The objective is to study multi-material products recycling, without previous sorting, aiming the use of the resulting material in applications with added value. The research is divided in three parts: (I) Bibliographic Review, (II) Practical Study A and (III) Practical Study B. Bibliographic Review presents the scientific and theoretic context regarding the central themes for later discussion of the results obtained in the practical parts. Practical Study A involves the reprocessing of multi-material toothbrushes through micronization. Subsequently, the resulting material is characterized by scanning electron microscopy (SEM), density test, tensile test and dynamic mechanical analysis (DMA). It is also presented the selection of potential areas of application for the new recycled material through Materials Properties Charts and a viability test of the selected application. In Practical Study B, two samples of different particle sizes were used to evaluate the influence of the recycled material’s particle sizes. In the characterization stage, in addition to the tests conducted in Study A, granulometric distribution, hardness test, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were also performed. The results demonstrated the technical feasibility of reprocessing multi-material toothbrushes through the traditional mechanical recycling process, without previous sorting. The recycled material presented potential for application in synthetic laminates for shoes and components production. Regarding the particles size influence, it was found that there was no significant influence in the resulted material. There is also the technological contribution which is the proposition of an alternative for the recycling of theoretically "non-recyclable" products, contributing to the reduction of solid waste generation.