Efficient Modelling of Chip Formation in Orthogonal Cutting Based on Isogeometric Analysis and Modern Methods for Material Characterization

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The proposed project considers the numerical simulation of chip formation and its potential to estimate process parameters for cutting processes. Also available in commercial software, the numerical simulation of chip formation based on the finite element method is a commonly used approach to predict the complex thermo-mechanical effects in cutting; in particular in the vicinity of the cutting edge. However, the state of the art shows limitations, i.e. on the one hand the actual chip formation simulations permit only the representation of very short process sequences and on the other hand their underlying models are of limited validity; in particular in terms of the quantitatively prediction of process values such as forces, stresses, strains, temperatures, and chip shapes. These limitations are partially due to insufficient material and friction models, however, there exists clear evidence that the utilized finite element meshes (refinement, element type, element deformation and orientation) have a strong influence not only on the accuracy of the numerical result, but also on the general phenomena that can be captured. This includes in especially the development of shear bands. These dependencies are intended to be resolved via the use of modern numerical methods, namely isogeometric analysis (IGA) and space-time finite elements.The specific scientific aim of the proposed project is to develop a modern numerical analysis tool for chip formation based on isogeometric analysis and the in computational fluid dynamics already established Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) method. The new tool is to be assessed in terms of efficiency and accuracy, in particular regarding effects in the primary and secondary shear zone, but also the workpiece surface zone. It has to be supported by modern methods of material characterization. On the methodological side, an understanding of the behavior IGA presents when modeling dynamic contact problems with thermodynamically coupled material equations. Especially the significant reduction of numerical errors, which are induced through remeshing steps, are expected to lead to an increase in numerical accuracy. This constitutes an important step for chip formation simulation and will immediately improve its applicability.