Multiscale analysis of flow and contact mechanisms in the stream finishing process for local topography adjustment

• Applicant: Professor Dr.-Ing. Volker Schulze
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 536576651

The aim of the planned research project is the demand-oriented local topography adjustment on real workpieces in stream finishing by generating specific particle contact mechanisms and simultaneously predicting the resulting material removal through process simulation. By characterizing the flow field regarding the formation of stagnation areas or flow separation, a method for adjusting the workpiece orientation will be derived to achieve the most efficient machining. Additionally, the occurring contact mechanisms will be simulated and identified depending on the local flow boundary conditions. This includes examining and describing the interactions between particles within the workpiece area and between individual particles and the workpiece surface. Furthermore, the specific material removal rates of different contact types will be experimentally determined, and the transferability of macroscopic removal descriptions will be investigated. The removal description will be integrated into the simulation model for topography adjustment. In the research project, initially, a three-sided prismatic grinding granulate will be characterized, and a process simulation will be built using the Discrete Element Method. The validated simulation will be used for flow field analysis (macro-level) to analyze the flow conditions and investigate particle interactions with the workpiece. This will lead to a method for optimal workpiece orientation. Building upon this, a simulative analysis of the contact mechanisms will be conducted at the meso-level between individual particles and a planar workpiece surface, as well as the interactions among particles in the vicinity of the workpiece. By correlating the contact mechanisms with applied pressures, velocities, flow directions, and describing particle movements through motion equations, the mechanisms leading to different contact types will be formulated. The topographies associated with each contact type will be determined through analogy experiments on polished samples. To ensure transferability, the simulative and experimental analyses will also be performed on samples with defined waviness. The final transfer of findings to real process machining will ensure the general applicability of the approach. By integrating the relationships into a topography and removal model within the simulation software, an efficient process strategy will be derived. Upon completion of the research project, the applicability to a real component will be demonstrated, and the generated knowledge can be applied to a variety of components.

• DFG Programme: Research Grants