| Abstrakt: |
Multilevel constitutive models are a tool that allows to analyze in detail the deformation processes of metals and alloys. They allow to describe explicitly the physical mechanisms of deformation at different structural-scale levels, providing information about the evolving structure of materials as a result of thermomechanical effects. The work is devoted to machining processes modeling of metals and alloys, for which it is proposed to apply a two-level constitutive model to describe elastoplastic deformation of polycrystalline aggregates. The main mechanism of inelastic deformation is assumed to be the motion of edge dislocations along the slip systems of crystallites. At the macro-level (levels of the product and representative macro-volume) the model operates with mechanical variables (fields of displacements, strains, stresses and their velocities). At the meso-level, the elements are crystallites (grains, subgrains) that make up a representative macro-volume; the model describes shears on sliding systems, changes in the crystallites orientations, critical shear stresses, etc. The choice of the two-level model is based on the balance between accuracy and computational efficiency. The conceptual and mathematical formulation of the orthogonal cutting problem is considered, taking into account dynamic effects and friction in the contact zone. Siebel's and Coulomb-Amonton's laws are used to describe friction. [ABSTRACT FROM AUTHOR] |
