SLM-Topo: Development of a process specific topology optimization method for additive manufacturing of lightweight structures examplified by the SLM process

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The generative manufacturing close to the final geometries represents a milestone in the production technology of complex components. Methods such as selective laser melting (SLM) are powder-based beam melting processes, with high potential in future industrial use. In this case, however, the added value can not be generated solely by the application of this production technology to already designed components. Rather, the benefit can be enhanced by exploiting the design freedom gained. Furthermore, the SLM is subject to process-specific limitations, such as minimal detail size, overhang angle, etc., as well as challenges, such as the inherent link between process management, component geometry and resulting material properties. This results in a research gap in the systematic design of components which are to be manufactured in addition, taking into account both geometrical and material-specific properties. In order to develop a strategy, which takes into account, both the geometrical constraints and metallurgical defects during the manufacturing process, a new design concept has to be developed towards conventional design guidelines for SLM.For conventional topology optimization, isotropic, homogeneous material models are used which presuppose corresponding material properties in the component. In the case of additive manufactured parts, the material properties are distributed anisotropically and inhomogeneously across the component. In the context of generative manufacturing processes there is considerable potential that the calculated optimization results can be produced in the SLM process without the otherwise necessary manual re-work. The aim of this research project is thus to develop a topology optimization method, which specifically takes into account anisotropic and inhomogeneous material properties in order to obtain a component geometry, which is optimally adapted to the additive manufacturing process. The aim of the optimization is the maximization of the component stiffness, taking into account strength restrictions. This allows further lightweight design potentials in the field of additive production technology to be developed. The alloy AlSi10Mg, which is known from the material lightweight design and can also be processed excellently in the SLM process, will be used. The optimization of the topology is thereby extended to the material properties as resulting from the SLM process, and finally validated in component tests. The necessary research work will be carried out in cooperation between the IPEK – Institute for Product Engineering at the Karlsruhe Institute of Technology (KIT) and the IAM-WK – Institute for Applied Materials - IAM WK at the Karlsruhe Institute of Technology (KIT), using the extensive knowledge in the areas of topology optimization and material characterization.