A cross-domain approach modeling the flow characteristics and material removal of abrasive magnetorheological fluids for drag finishing

The application of abrasive magnetorheological fluids for drag finishing of milling tools has previously been investigated. This work introduces a novel approach enabling the spatially resolved analysis of the flow characteristics and the material removal of abrasive magnetorheological fluids during the finishing process. With this approach, analytical models for the yield stress, macroscopic constitutive models and material removal estimation equations are incorporated in a hybrid framework coupling finite-element-based magnetic field simulations with computational fluid dynamics. This framework represents a computationally efficient compromise between particle-based models on the microscopic level, which become highly inefficient on the macroscopic level and analytical material removal models only applicable for planar finishing surfaces. For this purpose, a dipole-dipole interaction model for yield stress estimation is implemented, followed by a macroscopic Bingham-Papanastasiou model accounting for the non-Newtonian behavior of the magnetorheological fluid. A modified Preston’s model is proposed, mapping the fluid velocity, pressure and shear stress to the material removal. These analytical models are then incorporated in the cross-domain framework implemented using COMSOL Multiphysics for spatially resolved analysis. The model is parameterized and cross-validated based on finishing experiments. Thereby, the microgeometry of workpieces made of high-speed steel is analyzed before and after the finishing process. It is shown, that material removal is highly affected both by pressure and shear stress within the fluid. The spatially resolved material removal model features good agreement with reference experiments for larger magnetic excitations while maintaining high computing efficiency.