Les alliages d’aluminium de la série 5xxx et 6xxx sont des matériaux de choix pour la carrosserie automobile. Le panneau extérieur est généralement en alliage 6xxx et le panneau intérieur en 5xxx. Les deux sont assemblés par sertissage. Le sertissage consiste à replier la tôle extérieure sur la tôle de renfort. Ce procédé peut conduire à des états de surfaces insatisfaisants pour la tôle externe. Ce travail porte sur la caractérisation de la pliabilité des alliages 6xxx. L’influence du taux de manganèse et du temps de traitement thermique de Bake Hardening a été examinée.Les mécanismes d’endommagement d’alliages d’aluminium 6xxx durant l’essai de pliage ont été déterminés expérimentalement et par éléments finis. Les alliages d’aluminium s’endommagent par la formation de bandes de localisation de la déformation à travers l’épaisseur de la tôle. Ces bandes de localisation entraînent la formation d’une ondulation de surface en peau externe, de striction puis fissuration des grains. Les travaux suivants ont été effectués :• quantification expérimentale de la localisation basée sur des observations EBSD,• étude de la localisation de la déformation par un modèle mécanique basée sur la microstructure,• étude de la striction de grains par plasticité cristalline.Les conclusions suivantes ont été tirées :• la texture initiale, de type aléatoire, permet d’expliquer l’initiation de la localisation de la déformation,• la répartition spatiale de la dureté et le taux d’écrouissage en grande déformation sont les paramètres principaux contrôlant la localisation de la déformation,• l’interaction entre premiers grains voisins est responsable de la striction des grains de la peau externe. / The need for weight reduction in the automotive industry has led to the development of aluminum alloys for body panels on a number of mass-produced vehicles. 6xxx series alloys are selected for outer panels. These panels are often joined to inner panels by hemming. A poor surface aspect after hemming may be observed on the outer panel. In present work, the influence of manganese content and of bake hardening time on the bendability of 6xxx series alloy sheets has been analyzed. Damage mechanisms during bending of 6xxx aluminum sheets have been characterized experimentally and simulated by a mechanical model. Damage is controlled by the development of through thickness strain localization. The localization leads to the development of surface instabilities, splitting of the outermost grains and then crack propagation. The following works have been done:• strain localization has been characterized by EBSD observations,• study of strain localization by mechanical model based on microstructure,• study of grains splitting by crystal plasticity.The following results have been concluded:• the random texture allows to explain the strain localization,• spatial variation of the yield stress and overall strain hardening are the most influence material parameters which control the strain localization,• interaction between first neighbour grains controls grain splitting.

The influences of a superheated steam environment and temperature on the nearthreshold crack growth behaviour of mild steel during rotating bending fatigue were investigated. A fatigue machine in which rotating bending is simulated was designed and built to allow continuous crack growth measurement. Experiments compared the threshold stress intensities (∆Kth ) for air at 24 °C, air at 160 °C and steam at 160 °C.Air at 160 °C yielded the lowest threshold stress intensity in both cases. Oxide thicknesses in the vicinity of the threshold were estimated from temper colours. The difference in threshold stress intensities can be explained by the concept of oxideinduced crack closure. / Dissertation (MEng (Metallurgical Engineering))--University of Pretoria, 2007. / Materials Science and Metallurgical Engineering / MEng / unrestricted

Aerospace structural components made from polymer matrix composites (PMCs) offer numerous advantages. Their high stiffness and high strength combined with low densities enable lower fuel consumption coupled with higher payloads. As a result, PMCs provide an important economic advantage over typical metallic airframes. Textile reinforcements for PMCs are made by assembling reinforcement fibres, typically carbon. Then, the textile reinforcements are typically cut into smaller pieces, stacked, draped and assembled into a dry assembly called a preform, the shape of which generally approaches that of the PMC part to be made. This manufacturing process is labour intensive and expensive. Novel thick, net-shape, drapable, high vf textile reinforcements used toward manufacturing aerospace PMCs are being developed at the University of Ottawa. The technology enables the manufacturing of flat, drapable multilayered near net-shape preforms. The bending and in-plane shear behaviours of such novel thick reinforcement textiles was investigated to understand and define the behaviour of such thick fabric reinforcements when formed into required shapes. A bending apparatus was developed for investigating the bending behaviour of these novel thick reinforcement fabrics and an articulated frame shear rig was used for investigating the in-plane shear behaviour. A non-destructive inspection method using infrared imaging was used for investigating and identifying flaws and defects in these thick, dry textile reinforcements, aiming at increasing the quality and reproducibility of the final PMC parts made from these reinforcements.

Carbon fibre reinforced polymer matrix composites (CF PMCs) are increasingly used in state-of-the-art aerospace applications. Aerospace manufacturers favour components made of CF PMCs over those made of traditional metallic alloys because of their light weight and corrosion resistance, which lead to significant improvements in fuel consump- tion, increased payload capability, and reduced maintenance and inspection costs. How- ever, manufacturing of CF PMC components is performed differently than traditional material in all stages – design, prototyping and production – and therefore, many com- mercial manufacturers have only recently begun producing components with CF PMCs. The first half of this thesis was written as a contribution to the CRIAQ COMP-501 project, which focusses on investigating the cost-effective procurement of airframe com- ponents that are manufactured from final-thickness, net-shaped, and through-thickness reinforced CF preforms. Reinforcement preforms were assembled from commercial 2D woven fabric using stacks of various configurations of structural through-thickness CF stitch. The contribution herein provides the results obtained from investigations into the mechanical behaviour of the relevant reinforcements, when subjected to pre-infusion op- erations typical to RTM VARTM; mechanical behaviour in compaction, shear (draping) and bending (forming). The second half of this thesis presents the major developments which were made to an alternative process for producing thick 3D preforms with great versatility, a process originally proposed as a candidate for supplying preforms to the COMP-501 project. This process interfaces a proprietary kinematic drape optimization (CAD) software with proprietary automated dry fibre placement assembly (CAM) machinery to produce vari- able or final-thickness reinforcements which are highly-drapable and can lay steered tow yarns.

Den här rapporten är en del av ett examensarbete på 22,5 högskolepoäng inom högskoleingenjörsprogrammet i innovationsteknik och design och utförs vid Karlstads universitet under vårterminen 2017. Examensarbetet utförs på uppdrag av Rejlers AB som är ett svenskt teknikkonsultbolag. Rejlers har under två års tid tillverkat och testat en prototyp för bockning av ståldetaljer. Prototypen i sin nuvarande form anpassar automatiskt ståldetaljen efter slutanvändarens behov, genom inkrementell formning. När ståldetaljer med stort tvärsnitt bockas uppstår problem i form av plastisk deformation av komponenter i maskinen. Projektet grundar sig i att Rejlers nu har inlett projekteringen av nästa version av prototypen, för att implementera förbättringsförslag som uppkommit vid testkörning och lösa problemet med deformation av maskinens komponenter. Syftet med arbetet är att skapa underlag för detaljkonstruktion och dimensionering av prototyp nummer två. Problemet löses genom att tillämpa produktutvecklingsprocessen och leverera ett konceptuellt lösningsförslag i form av en layoutkonstruktion. I layoutkonstruktionen integreras kritiska komponenter på ett skalbart sätt, så att framtida arbete med dimensionering och detaljkonstruktion underlättas. / This report is part of a thesis of 22.5 ECTS for a Degree of Bachelor of Science in Innovation and Design Engineering at Karlstad University during the 2017 spring semester. The thesis is carried out on behalf of Rejlers AB, a Swedish technology consultancy. Rejlers has manufactured and tested a prototype for two years for bending steel parts. The prototype in its current form automatically adjusts the steel part to the end user's needs, by incremental shaping. When steel parts with a large cross-section are bent, problems arise in the form of plastic deformation of components in the machine. The project is based on the fact that Rejlers has now started the design of the next version of the prototype, to implement improvement proposals that occurred during the test run and solve the problem of deforming components in the machine. The purpose of the work is to create the basis for detail design and dimensioning of prototype number two. The problem is solved by applying the product development process and delivering a conceptual solution in the form of a layout design. In the layout design, critical components are integrated in a scalable way, so that future work on dimensioning and detailing is facilitated.

Unstable Systems or Why Is My Junk So Raw? is an exploration in the raw aesthetics of exposed electronics; showing the complicated systems that make our everyday electronics work using the visual language of formalism to display these “broken” consumer electronics as art. The work in my thesis show explores the creative potential of death and impermanence through the failing of technology. The work in the exhibition combines my interest and childhood fascination in electronics as well as my experience with my father’s illness. Accidentally and intentionally broken TV’s and electronics are producing live glitches which emphasize the instability of these otherwise closed systems.

Fabrication of carbon infiltrated carbon nanotubes (CI-CNT) can result in large mechanical property variation, and methods to characterize properties usually involve destructive testing. Finding a non-destructive way to test for stiffness of this material reduces the number of parts that have to be made. It also simplifies testing of complex parts. The stiffness of CI-CNT beams is related to the type of carbon material infiltrated between the carbon nanotubes (CNTs), how it interacts with the CNTs, and how much of it there is. The amount of material can be estimated using the density of the beam, and both the type of material and its interaction with the carbon nanotubes can be approximated through analysis of the Raman spectra taken at the surface. A combination of these two observations can be related to the effective material stiffness. The relationship can be fitted with a power function, with a variance of 1.41 GPa, which is about 11% of the maximum stiffness of the samples tested. This variance is similar to the larger variations in CI-CNT beam stiffnesses found in a single batch of beams.

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The presented thesis was created in cooperation with Siemens, s.r.o. and deals with the analysis of the bending of aluminium sheets. These products are used as conductors of electrical energy. The problem happened when the bending angle was 90 ° when there was a violation outside of the bend. The aim of the thesis is to verify whether the bend is correctly designed using analytical and empirical relations and the finite element method. Because of the requirement for running numerical simulation on one of the freely available software the Salome Meca program environment was used. The results of numerical simulation did not confirm that the violation should occur. In deeper analysis appeared doubts whether it is possible to correctly evaluated result only by data from tensile test. In the final part, there are recommended some experiments which would be necessary for the correct calibration of the ductil fracture criteria.

The paper evaluates technological, economic and construction aspects of the component production and the design of the tool serving for large-scale production of the S355MC steel rack component. Use of a progressive tool combining cutting and bending operations in four steps has been decided as the most appropriate according to literature study. Based on the need of production of two plane-symmetrical pieces at a time, the tool will produce both pieces simultaneously, which is economically advantageous. The tool is designed for use on the Arisa 630t mechanical press. Material will be winded off the roll, flattened and pushed into the tool by a precision feeder. The total cost of production of the component was set at 18.80 CZK.