Efficient Modelling of Chip Formation in Orthogonal Cutting Based on Isogeometric Analysis and Modern Methods for Material Characterization
Final Report Abstract
Numerical methods are frequently used for the simulation of the chip formation process of metal cutting manufacturing processes [Arr13]. One main advantage of numerical methods (especially the finite element method) is the possibility of spatial and temporal resolution of the state variables. With the help of these models, predictions of fundamental state variables such as the stresses and strains in the material as well as the resulting forces are possible. Furthermore, chip morphology as well as practical parameters such as tool wear or chip breakage can be simulated. To date, numerical models are still in need of improving the prediction accuracy. Only few works actually deal with the fundamental numerics of the simulation system or with the influences of the meshing as well as the boundary formulation, by which the prediction accuracy of chip formation simulations can be substantially improved. Based on this motivation, the present project investigated to what extent novel numerical methods such as the space-time finite element method as well as isogeometric analysis can be used to improve the prediction accuracy of chip formation simulations in orthogonal cutting. At the Chair for Computational Analysis of Technical Systems, a boundary-conforming Eulerian method using space-time finite elements for structural analysis of elastic materials was developed, implemented, and tested. This approach offers improved accuracy in determining displacements and better stability in terms of avoiding locking effects, but the computational cost is higher compared to a classical approach. After a switch in the development framework, a plasticity material model utilizing the Johnson-cook hardening formulation in combination with Isogeometric Analysis was implemented and validated with data provided by ISF. A contact formulation with rigid B-Splines extended this implementation and is currently under development to include friction between the tool and the workpiece. At the Institute of Machining Technology of the TU Dortmund University, input, validation and comparison data were determined in close cooperation with CATS according to the current state of scientific knowledge. First, the flow-stress behavior of the materials and the friction behavior between the materials and the cemented carbide tools used were characterized as input data for the simulations. Subsequently, chip formation tests were conducted to determine the thermomechanical loads of the chip formation zone and the chip morphology depending on material and cutting values. The application of this data was the simulation validation. Finally, comparative simulations were carried out in different commercial systems both in orthogonal cutting and for test cases, like the uniaxial compression test to further validate the new numerical methods.
Publications
-
Comprehensive Comparison of Different Meshing Approaches for FE-based Chip Formation Simulation for 1045 Steel. EUROMAT 2019 C9 Symposium, 03.09.2019, Stockholm, Schweden
Rödder, T.; Saelzer, J.; Tiffe, M. & Zabel, A.
-
Experimental Analysis of the Friction Behaviour in Cutting In: Production at the leading edge of technology - Proceedings of the 9th Congress of the German Academic Association for Production Technology (WGP), 30.9.-2.10. 2019, Hamburg, Hrsg.: Wulfsberg, J. P.; Hintze, W.; Behrens, B.-A., Springer Vieweg
Saelzer, J.; Zabel, A.; Biermann & D.
-
Temperaturmessung an Span und Werkzeug. Industrial Quality - Testen, Prüfen, Messen, Sonderausgabe, Kuhn Fachverlag, Villingen-Schwenningen, S. 9-10, ISSN 2190-3107
Berger, S.; Saelzer, J.; Zabel, A. & Biermann, D.
-
Computing the jump-term in space-time FEM for arbitrary temporal interpolation. Proceedings of the YIC 2021 - VI ECCOMAS Young Investigators Conference. Editorial Universitat Politècnica de València.
Salzmann, Eugen; Zwickey, Florian & Elgeti, Stefanie
