This master’s thesis focuses on the concept of large-lot manufacturing of sheet metal component made from DC01 steel. Based on forethought, the method of compound tool combining shearing and bending was chosen. The theoretical part analyses used technologies in detail. In the next part specific course of manufacture was created and supplied with technological calculations. Based on all needed facts the tool was designed and after that forming machine, LDC 160 crank press, was chosen. At the end the usability of designed concept was confirmed with economical calculations.

This project is conceived within the master's degree in engineering technology and industry management (M2I-K Engineering) technology by design of the brake disc cover in compound tool, with year production 500 000 pcs. The material is deep-drawn sheet metal 11 305.21, 1 mm thickness. It is based on the literature studies about forming and calculation was suggested several variants of the present components. The proposed tool is clamped in the crank press LDC 400 firm Šmeral with a nominal force of 4000 kN. The functional parts are made from steel 19 573. The proposed technology of the deep drawing was verified by using simulation program AutoForm.

Die Entwicklung von verzweigten Blechstrukturen, die mit Hilfe der innovativen Verfahren Spaltprofilieren und Spaltbiegen hergestellt werden, erfordert eine Erweiterung des verwendeten Produktentwicklungsansatzes. Im Sonderforschungsbereich 666 wurde dafür der Algorithmen-basierte Produktentwicklungsprozess eingeführt. Im Unterschied zu etablierten Produktentwicklungsprozessen, werden mathematische Optimierungsalgorithmen mit Randbedingungen aus den formalisierten Anforderungen wie Bauraumrestriktionen oder Lasten verwendet, um optimierte verzweigte Blechstrukturen zu entwickeln. Da in der mathematischen Optimierung nicht alle Informationen aus der Fertigung berücksichtigt werden können, müssen die optimierten verzweigten Blechstrukturen fertigungsgerecht optimiert werden. Dazu wird in diesem Beitrag zunächst ein Fertigungsrestriktionsmodell eingeführt. Basierend auf den gewonnen Erkenntnissen aus dem Modell wird dann ein Ansatz zur teilautomatisierten fertigungsorientierten Optimierung von verzweigten Blechstrukturen eingeführt und anhand eines Beispiels validiert.

In a Sheet Metal Forming (SMF) operation, complex geometries in multi-stage forming processes are mostly common. Forming a blank, major and minor straining willoccur. Follow the straining of the blank elements over the forming process will provide its strain paths. The strain paths can be visualized in a Forming Limit Diagram(FLD); with a Forming Limit Curve (FLC) corresponding to the strained material.In the diagram, the determination whether an element is critical due to fracture ornecking is determined. Utilizing the FLD, the formability of a material is defined;the elements and their paths are however linear. Manufacture a sheet metal usinga multi-stage forming process will contribute to Non-Linear Strain Paths (NLSP).Thus, the FLD is no longer valid. Providing a tool from the company RISE IVF AB to be used for pre-strainingoperations, the objective of this thesis work is to enhance and investigate the possibility of generating the three main strain paths - uniaxial tension, plane strain,equibiaxial tension - of the dual-phased steel DP800. This study is in collaborationwith Volvo Cars Body Components (VCBC) in Olofström, where the pre-strainingwill be used in a future study of the SMF non-linear behaviour. Utilizing the finiteelement software AutoForm - specialized on SMF operations - this numerical basedstudy can be conducted. The ability of generating the three main strain paths will be achieved by modifying the blank geometries and provided tooling. By changing the dimensions ofthe punch and draw beads, critical regions and forced concentrated straining weresupposed to be achieved. These changes are implemented with the intention to fulfillthe criterion of the straining in terms of magnitude and gradient. The result from the simulations shows that the modifications have different effecton both the straining level and gradient. The modifications of both the draw beadand the punch were not of any significant use, while the blank dimension was mostvital when generating sufficient strain paths. Hence, the tooling modifications withinthis thesis work did not enhance the prediction of the three strain paths.

Coupling of material, process, and performance models is an important step towards a fully integrated material-process-performance design of structural components. In this research, alternative approaches for introducing the effects of manufacturing and material microstructure in plasticity constitutive models are studied, and a cyberinfrastructure framework is developed for coupled process-performance simulation and optimization of energy absorbing components made of magnesium alloys. The resulting mixed boundary/initial value problem is solved using nonlinear finite element analysis whereas the optimization problem is decomposed into a hierarchical multilevel system and solved using the analytical target cascading methodology. The developed framework is demonstrated on process-performance optimization of a sheetormed, energy-absorbing component using both classical and microstructure-based plasticity models. Sheetorming responses such as springback, thinning, and rupture are modeled and used as manufacturing process attributes whereas weight, mean crush force, and maximum crush force are used as performance attributes. The simulation and optimization results show that the manufacturing effects can have a considerable impact on design of energy absorbing components as well as the optimum values of process and product design variables.

With the increased focus on reducing carbon emissions in today’s society, several industries have to overcome new challenges, where especially the automotive industry is under a lot of scrutiny to deliver improved and more environmentally friendly products. To meet the demands from customers and optimize vehicles aerodynamically, new cars often contain complex body geometries, together with advanced materials that are introduced to reduce the total vehicle weight. With the introduction of the complex body components and advanced materials,one area in the automotive industry that has to overcome these challenges is manufacturing engineering, and in particular the departments working with the sheet metal forming process. In this process complex body component geometries can lead to non-linear strain paths and stretch bending load cases, and newly introduced advanced materials can be prone to exhibit behaviour of edge cracks not observed in conventional sheet metals. This thesis takes it onset in the challenges seen in industry today with predicting failure of the three complex load cases: Non-Linear Strain Paths, Stretch-Bending,and Edge Cracks. Through Finite Element simulation attempts are made to accurately predict failure caused by aforementioned load cases in industrial components or experimental setups in an effort to develop post-processing methods that are applicable to all cases.

Bending deformation characteristics of monolithic, bi-layer and tri-layer laminate sheet materials are studied using Analytical and FE models in this work. The analytical model, based on advanced theory of pure bending considers von Mises yielding, Ludwik hardening law and Bauschinger effect for various laminate constituent thickness ratios. The principal stresses and strains through the thickness and, change in relative thickness at specified bend curvatures are obtained as a function of increasing curvature during bending. Additionally, 2D and 3D finite element (FE) based models for bending are developed to overcome simplifications of the analytical models such as the effect of specimen width on strain distribution. Further, to experimentally assess and validate bending characteristics from the analytical models, a new experimental bend test-jig that is closer to pure bending is developed. The experimental set-up is an open concept design that allows access to the tensile surface as well as through-thickness region for recording and analyzing strains using an online strain mapping system based on digital image correction (DIC) method. Experimental bending is carried out on annealed AA2024 monolithic aluminum alloy sheet and Steel/Aluminum (SS400/AA1050) bi-layer laminate sheet at different thickness ratios. The model and experiments are studied in terms of stress and strain distribution as a function of relative thickness for different clad to matrix thickness ratios. Further the case of simultaneous bending and stretching over small radius bending is analyzed for limit strain prediction using an existing limit strain criterion based on major strain acceleration. An angular stretch bend test is used to subject an hour-glass shaped AA20240-O aluminum sheet specimen to simultaneous stretching and bending deformation while continuously imaging the critical tensile surface region using an optical camera. The strain development in the critical region is subsequently analyzed using digital image correlation (DIC) method. The effect of DIC parameters such as facet size, facet step, and effect of curve fitting procedures on limit strain are studied. An average limit strain of 0.2 is obtained for AA2024 for a facet size of 9x9 pixels, a facet step of 5 pixels and by applying a 5th order polynomial curve fit to the strain data. The results obtained are comparable with a limit strain of the material. The results are compared with a commercially available tri-layer laminate sheet material Alclad 2024 that has 80 μm thin layer of soft AA1100 on both surfaces of harder AA2024 core material. An improved stretch bendability limit strain of 0.24 for Alclad 2024 tri-layer specimen was predicted by utilizing the major strain acceleration criterion. The thin AA1100 protective layer produced a positive effect on the stretch bendability of Alclad 2024 when compared with monolithic AA2024 specimen. / Thesis / Doctor of Philosophy (PhD)

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Os processos de conformação de chapas metálicas são largamente usados na fabricação de produtos em diversas áreas, desde partes aeronáuticas a utensílios domésticos, devido a sua alta produtividade, confiabilidade e baixo custo de produção. Para se atingir tais qualidades, o desenvolvimento de um produto conformado deve levar em consideração os fatores metalúrgicos da chapa a ser usada. As chapas são geralmente produzidas por laminação a frio, o que as levam ter propriedades mecânicas distintas em relação à direção de laminação. Para modelar esta anisotropia, vários critérios de escoamento foram propostos. A fim de verificar a influência do critério de escoamento na distribuição de deformação no produto conformado, este trabalho teve como objetivo implementar os critérios de Hill (1979) e de Barlat et al. (1993) em um programa acadêmico que modela o processo de conformação de chapas via o método dos elementos finitos. O critério de Hill (1979) foi implementado e apresentou bons resultados, em acordo com a literatura. O critério de Barlat et al. (1993) foi deduzido em sua formulação para elementos finitos, embora não implementado. Com o critério de Hill (1979) foi possível analisar a distribuição da deformação para várias superfícies de escoamento, alterando-se apenas o valor de um parâmetro da função de escoamento. / The sheet metal forming processes are widely used in the manufacturing of products in several areas, from aviation to household utensils, due to its high productivity, reliability and low cost of production. To achieve these qualities, the design of a product made by sheet metal forming should take into consideration the metallurgical factors of the blank to be used. The blank is usually cold-rolled, which leads to different mechanical properties in the rolled and transverse directions. To take into account this anisotropy, several yield criteria were proposed. To check the influence of the yield criterion in the strain distribution of the final product, this study focused on the implementation of the yield criteria of Hill (1979) and Barlat et al. (1993) in an academic computer program that modeled the sheet metal forming process by the finite element method. The Hill (1979) criterion was implemented and had good results, in accordance with the literature. The Barlat et al. (1993) criterion was formulated for a finite element method analysis, though not implemented. By using Hill\'s non-quadratic yield criterion it was possible to analyze the strain distribution for various yield surfaces, changing only the value of one parameter of the yield function.

Entre os processos de fabricação mecânicos atuais destacam-se os processos de conformação de chapas metálicas devido à sua produtividade e confiabilidade e a seus baixos custos de produção, baixo consumo de material e produtos nos formatos bem próximos dos esperados nas fases de projeto. Isto só é possível se todas as variáveis do projeto e do processo estiverem conforme as especificações prévias, exigidas principalmente em setores da indústria tais como o aeronáutico e o automobilístico. Um recurso útil para se alcançar estas expectativas é o estudo da estricção e da conformabilidade em chapas metálicas, representadas em diagramas de limite de conformação (DLC), os quais, aliados à análise numérica através do Método dos Elementos Finitos, permitem predições a respeito das variáveis de projeto. Este trabalho tem como objetivos rever e aplicar conceitos relativos a estes aspectos. O objetivo principal deste trabalho é de dispor uma metodologia de avaliação e otimização para o processo de estampagem, utilizando-se elementos finitos e DLC. Uma modificação no método de Marciniak-Kuczynski é utilizada para a obtenção do DLC. Busca-se com isto uma contribuição para a redução de custos em aplicações industriais com o uso desta metodologia através da diminuição das fases de tentativas e erros em projeto e reforma de estampos (try-outs). / Nowadays, sheet metal forming processes have an important role amongst the mechanical manufacturing processes, because they are characterized by high productivity and reliability at low cost, low material waste and near net shapes from design. This is achieved by controlling the design and process parameters according to initial constraints. This scenario is common at aeronautic and at automobilistic productions . These results are obtained by studies of necking and formability in sheet metals and by the use of forming limit diagrams (FLD) and finite element numerical analysis to predict design parameters. This work reviews these concepts and presents a methodology for optimization of deep drawing processes, by using finite element method and FLD. A modification of the Marciniak-Kuczynski method has been introduced to obtain the FLD. Once this methodology has been performed, it can be possible to reduce try-outs in sheet metal dies and costs reduction can also be obtained.