Multi-material-design (MMD) is commonly realized through the combination of thin sheet metal and fibre reinforced plastics (FRP). To maximize the high lightweight potential of the material groups within a multi-material system as good as possible, a material-adapted and particularly fibre adjusted joining technology must be applied. The present paper focuses on two novel joining technologies, the Flow Drill Joining (FDJ) method and Spin-Blind-Riveting (SBR), which were developed for joining heavy-duty metal/composite hybrids. Tests were carried out with material combinations which are significant for lightweight constructions such as aluminium (AA5083) and carbon fibre-reinforced polyamide in sheet thickness of 1.8 mm. The mechanical testing and manufacturing of those multi-material joints was investigated.

Multi-material-design (MMD) is commonly realized through the combination of thin sheet metal and fibre reinforced plastics (FRP). To maximize the high lightweight potential of the material groups within a multi-material system as good as possible, a material-adapted and particularly fibre adjusted joining technology must be applied. The present paper focuses on two novel joining technologies, the Flow Drill Joining (FDJ) method and Spin-Blind-Riveting (SBR), which were developed for joining heavy-duty metal/composite hybrids. Tests were carried out with material combinations which are significant for lightweight constructions such as aluminium (AA5083) and carbon fibre-reinforced polyamide in sheet thickness of 1.8 mm. The mechanical testing and manufacturing of those multi-material joints was investigated.

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.

Micro-Powder Injection Moulding (Micro-PIM) technology is one of the key technologies that permit to fit with the increasing demands for smaller parts associated to miniaturization and functionalization in different application fields. The thesis focuses first on the elaboration and characterization of polymer-powder mixtures based on 316L stainless steel powders, and then on the identification of physical and material parameters related to the sintering stage and to the numerical simulations of the sintering process. Mixtures formulation with new binder systems based on different polymeric components have been developed for 316L stainless steel powders (5 µm and 16 µm). The characterization of the resulting mixtures for each group is carried out using mixing torque tests and viscosity tests. The mixture associated to the formulation comprising polypropylene + paraffin wax + stearic acid is well adapted for both powders and has been retained in the subsequent tests, due to the low value of the mixing torque and shear viscosity. The critical powder volume loading with 316L stainless steel powder (5 µm) according to the retained formulation has been established to 68% using four different methods. Micro mono-material injection (with 316L stainless steel mélange) and bi-material injection (with 316L stainless steel mélange and Cu mélange) are properly investigated. Homogeneity tests are observed for mixtures before and after injection. A physical model well suited for sintering stage is proposed for the simulation of sintering stage. The identification of physical parameters associated to proposed model are defined from the sintering stages in considering 316L stainless steel (5 µm)mixtures with various powder volume loadings (62%, 64% and 66%). Beam-bending tests and free sintering tests and thermo-Mechanical-Analyses (TMA) have also investigated. Three sintering stages corresponding to heating rates at 5 °C/min, 10 °C/min and 15 °C/min are used during both beam-bending tests and free sintering tests. On basis of the results obtained from dilatometry measurements, the shear viscosity module G, the bulk viscosity module K and the sintering stress σs are identified using Matlab® software. Afterwards, the sintering model is implemented in the Abaqus® finite element code, and appropriate finite elements have been used for the support and micro-specimens, respectively. The physical material parameters resulting from the identification experiments are used to establish the proper 316L stainless steel mixture, in combination with G, K and σs parameters. Finally, the sintering stages up to 1200 °C with three heating rates (5 °C/min, 10 °C/min and 15 °C/min) are also simulated corresponding to the four micro-specimen types (powder volume loading of 62%, 64% and 66%). The simulated shrinkages and relative densities of the sintered micro-specimens are compared to the experimental results indicating a proper agreement

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.

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.

Bei dem 3D-Multimaterialdruck handelt es sich um ein Verfahren, mit dem es erstmals möglich ist, mehrere Materialien mit unterschiedlichen Eigenschaften in einem Arbeitsgang zu verdrucken. Um die geometrischen und physikalischen Beschränkungen aufzubrechen, wurde an der Professur Elektrischen Energiewandlungssysteme und Antriebe ein Verfahren entwickelt, mit dem es möglich wird, ganze elektromagnetische Energiewandler in einem Arbeitsgang herzustellen. Gleichzeitig lassen sich völlig neue Bauformen von Maschinen realisieren. Durch den Austausch von konventionellen Isolationsmaterialien durch Keramikisolation, werden die thermischen Eigenschaften von Elektromotoren signifikant verbessert.

In diesem Beitrag werden die magnetischen Eigenschaften von ferromagnetischen Proben, welche mittels des neuen 3D-Multimaterialdruckverfahrens (3DMMD) hergestellt wurden, mit herkömmlichen Magnetkreismaterialien verglichen. Dazu wird zunächst die Technologie des Druckverfahrens sowie das Messprinzip und der Versuchsstand beschrieben. Im Weiteren wird ein Überblick über die Materialentwicklung gegeben und die Messergebnisse diskutiert. Es folgt die Betrachtung relevanter Einflüsse bei der Herstellung von Magnetkreisen sowie der Vergleich der Messergebnisse verschiedener Materialien. / In this paper, the magnetic properties of ferromagnetic samples produced using the new 3D multi-material printing process (3DMMD) are compared with conventional magnetic circuit materials. First the technology of the printing process as well as the measuring principle and the test bench are described. Furthermore, an overview of the material development is given and the measurement results are discussed. This is followed by the consideration of relevant influences in the production of magnetic circuits and the comparison of the measurement results of different materials.

No description available.

<p>The design of vehicle components for crashworthiness is one of the most challenging problems in the automotive industry. The safety of the occupants during a crash event relies on the energy absorption capability of vehicle structures. Therefore, the body components of a vehicle are required to be lightweight and highly integrated structures. Moreover, reducing vehicle weight is another crucial design requirement since fuel economy is directly related to the mass of a vehicle. In order to address these requirements, various design concepts for vehicle bodies have been proposed using high-strength steel and different aluminum alloys. However, the price factor has always been an obstacle to completely replace regular body steels with more advanced alloys. To this end, the integration of numerical simulation and structural optimization techniques has been widely practiced addressing these requirements. Advancements in nonlinear structural design have shown the promising potential to generate innovative, safe, and lightweight vehicle structures. In addition, the implementation of structural optimization techniques has the capability to shorten the design cycle time for new models. A reduced design cycle time can provide the automakers with an opportunity to stay ahead of their competitors. During the last few decades, enormous structural optimization methods were proposed. A vast majority of these methods use mathematical programming for optimization, a method that relies on availability sensitivity analysis of objective functions. Thus, due to the necessity of sensitivity analyses, these methods remain limited to linear (or partially nonlinear) material models under static loading conditions. In other words, these methods are no able to capture all non-linearities involved in multi-body crash simulation. As an alternative solution, heuristic approaches, which do need sensitivity analyses, have been developed to address structural optimization problems for crashworthiness. The Hybrid Cellular Automaton (HCA), as a bio-inspired algorithm, is a well-practiced heuristic method that has shown promising capabilities in the structural design for vehicle components. The HCA has been continuously developed during the last two decades and designated to solve specific structural design applications. Despite all advancements, some fundamental aspects of the algorithm are still not adequately addressed in the literature. For instance, the HCA numerically implemented as a closed-loop control system. The local controllers, which dictate the design variable updates, need parameter tuning to efficiently solve different sets of problems. Previous studies suggest that one can identify some default values for the controllers. However, still, there is no well-organized strategy to tune these parameters, and proper tuning still relies on the designer’s experience.</p> <p> </p> <p> Moreover, structures with multiple materials have now become one of the perceived necessities for the automotive industry to address vehicle design requirements such as weight, safety, and cost. However, structural design methods for crashworthiness, including the HCA, are mainly applied to binary structural design problems. Furthermore, the conventional methods for the design of multi-material structures do not fully utilize the capabilities of premium materials. In other words, the development of a well-established method for the design of multi-material structures and capable of considering the cost of the materials, bonding between different materials (especially categorical materials), and manufacturing considering is still an open problem. Lastly, the HCA algorithm relies only on one hyper-parameter, the mass fraction, to synthesize structures. For a given problem, the HCA only provides one design option directed by the mass constraint. In other words, the HCA cannot tailor the dynamic response of the structure, namely, intrusion and deceleration profiles.</p> <p> </p> <p>The main objective of this dissertation is to develop new methodologies to design structures for crashworthiness applications. These methods are built upon the HCA algorithm. The first contribution is about introducing s self-tuning scheme for the controller of the algorithm. The proposed strategy eliminates the need to manually tune the controller for different problems and improve the computational performance and numerical stability. The second contribution of this dissertation is to develop a systematic approach to design multi-material crashworthy structures. To this end, the HCA algorithm is integrated with an ordered multi-material SIMP (Solid Isotropic Material with Penalization) interpolation. The proposed multi-material HCA (MMHCA) framework is a computationally efficient method since no additional design variables are introduced. The MMHCA can synthesize multi-material structures subjected to volume fraction constraints. In addition, an elemental bonding method is introduced to simulate the laser welding applied to multi-material structures. The effect of the bonding strength on the final topology designs is studied using numerical simulations. In the last step, after obtaining the multi-material designs, the HCA is implemented to remove the desired number of bonding elements and reduce the weld length.</p> <p> </p> <p>The third contribution of this dissertation is to introduce a new Cluster-based Structural Optimization method (CBSO) for the design of multi-material structures. This contribution introduces a new Cluster Validity Index with manufacturing considerations referred to as CVI_m. The proposed index can characterize the quality of the cluster in structural design considering volume fraction, size, interface as a measure of manufacturability. This multi-material structural design approach comprises three main steps: generating the conceptual design using adaptive HCA algorithm, clustering of the design domain using Multi-objective Genetic Algorithm (MOGA) optimization. In the third step, MOGA optimization is used to choose categorical materials in order to optimize the crash indicators (e.g., peak intrusion, peak contact force, load uniformity) or the cost of the raw materials. The effectiveness of the algorithm is investigated using numerical examples.</p>