Development, numerical simulation and experimental characterization of selective laser melting (SLM) microstructures with deliberately introduced dissipation

由于新型材料和创新的制造技术，轻量化设计的概念在过去几年中变得越来越普遍。不幸的是，由此产生的技术部件通常对不希望的振动更敏感。本提案的目的是通过采用新颖的制造技术来开发多功能微结构，以整体和多功能的方式将轻量化设计与有效和可控的耗散特性结合起来，直接从源头解决这些不良影响。具体而言，我们利用选择性激光熔化（SLM）的优势，以产生预期的微观结构。选择性激光熔化（SLM）是基于粉末融合的增材制造（AM）工艺的最新且非常有前途的代表。由于分层生产，SLM工艺能够生产出传统制造工艺无法获得的高度复杂的几何形状。机械设计的这种范式转变已经使新型微结构的制造成为可能，这些微结构通常在重量和刚度方面进行优化。为了将这些轻量化设计与期望的阻尼特性结合起来，基于微摩擦学、固体材料阻尼和流体中的粘性阻尼等不同物理耗散现象，提出了四个基本的微观结构概念：一种是由松散的金属粉末组成的微观结构（已经由SLM工艺提供），一种是由高粘性油填充的多孔微观结构，一种是由固化聚合物树脂填充的轻质金属晶格结构，最后一种是由内部微摩擦元件组成的智能微观结构，可以抑制单个变形模式。为了研究和实施所提出的概念，两个参与机构在实验和制造专业知识以及建模和仿真相关专业知识方面的能力以最佳方式结合在一起。为了研究潜在的物理耗散现象，将建立精确的力学微尺度模型。随后，这些微尺度模型将被转换为均匀化的宏观尺度模型，从而生成预测仿真工具，从而允许对实际相关设计部件提出的阻尼概念进行有效的评估和优化。对定制样品进行详细的实验研究将有助于深入的微观结构表征，模型参数确定，并最终验证衍生模型和验证提出的耗散概念。基于最有希望的概念，将制造切削工具形式的原型，以便在实际相关环境中评估可实现的阻尼特性。

Due to novel materials and innovative manufacturing technologies, the concept of lightweight design has become more and more prevalent within the last years. Unfortunately, the resulting technical components are often more sensitive to undesired vibrations. The aim of this proposal is to address these unwanted effects directly at their source by employing novel manufacturing technologies for the development of multi-functional microstructures that combine lightweight design with effective and controllable dissipation characteristics in an integral and multi-functional way. Concretely, we exploit the advantages of selective laser melting (SLM), a recent and very promising representative of powder-fusion-based additive manufacturing (AM) processes, in order to generate the intended microstructures. Due to the layer-wise production, the SLM process is capable of producing highly complex geometries that cannot be obtained by conventional manufacturing processes. This paradigm shift in mechanical design has already enabled the manufacturing of novel microstructures typically optimized in terms of weight and stiffness. In order to combine these lightweight designs with the desired damping characteristics, four fundamental microstructural concepts based on different physical dissipation phenomena such as micro-tribology, solid material damping and viscous damping in fluids are proposed: a microstructure consisting of loose metal powder (that is already provided by the SLM process), a porous microstructure filled with highly viscous oil, a lightweight metal lattice structure filled with solidified polymer resin, and finally an intelligent microstructure consisting of internal micro-friction elements that allow for damping of individual deformation modes. In order to investigate and implement the proposed concepts, the competences of the two participating institutions in terms of experimental and manufacturing expertise on the one hand and modeling and simulation related know-how on the other hand are combined in an optimal way. Accurate mechanical microscale models will be developed in order to investigate the underlying physical dissipation phenomena. Subsequently, these microscale models will be transferred into homogenized macroscale models, thus generating predictive simulation tools that allow for an efficient evaluation and optimization of the proposed damping concepts for practically relevant design parts. Detailed experimental investigations on custom-built samples will serve for an in-depth microstructure characterization, model parameter determination and eventually for verification of the derived models and validation of the proposed dissipation concepts. Based on the most promising concepts, a prototype in form of a cutting tool will be manufactured in order to assess the achievable damping characteristics also in a practically relevant environment.