Abstract
The present paper highlights the importance of size effect consideration during the modelling of material removal by cutting tool, especially when passing from maco-to-micro scales. For that, the presented study concerns an orthogonal case of down-cut milling where the chip thickness is evolving. Consequently, to capture the scale effect when passing from macro to micro dimensions, the theory of gradient plasticity were adopted.
After a basic explanation of the strain gradient approach, the elaboration of a cutting model by acting on a modified Johnson-Cook material law based on the strain gradient theory is formulated in ABAQUS (R)/EXPLICIT via its user subroutine VUMAT. From experimental point of view milling tests have been performed to validate the numerical cutting model in terms of specific cutting energy evolution according to the uncut chip thickness (UCT) variation. The obtained results put forward the significance of strain gradient hardening to fully capture the size effect phenomenon when the UCT attains a micro-level.