Numerical modelling of micro-machining of f.c.c. single crystal: Influence of strain gradients

Micro-cutting of single-crystal metal: Finite-element analysis of deformation and material removal

“…To our knowledge, three main modelling techniques are usually employed to simulate material removal: element deletion [29,38], arbitrary Lagrangian-Eulerian adaptive remeshing (ALE) [18,20,39] and smooth particle hydrodynamics (SPH) [27,40,41]. Our studies indicated that the three modelling techniques produce almost identical results for the cutting forces, however, the element deletion technique was the most computationally efficient [42].…”

“…The intention was to attain a good correlation with regard to cutting-force magnitudes (in contrast to prior studies [29]). As before, only Stage 2 of micro-cutting with a depth of 18 μm was considered.…”

“…Three of those were based on a simplified damage model; the respective criteria were based on principal strain, equivalent plastic strain and maximum shear strain. Next, an approach based on the shear strain accumulated over all slip systems was considered as per the work of Demiral et al [29]. Finally, a new shear strain-based criterion was proposed to account for anisotropy in the material-removal process, as follows: γ ) or the accumulated slip ( cr γ ) is attained, the element is removed.…”

“…Studies by Abolfazl et al [27] and Tajalli et al [28] showed that chip formation and cutting forces in single-crystal copper depended on the initial crystal orientations in the work-piece with respect to a cutting direction. Moreover, the works by Demiral et al [29] and Pal and Stucker [30], based on strain-gradient crystal-plasticity simulations, indicated that inhomogeneous plastic deformation could affect machinability of a work-piece. These studies lack comprehensive experimental validations.…”

“…It was claimed that the maximum-shear-strain-based damage model provided the most accurate prediction when compared to experimental data. On a related note, since extreme shear deformation usually occurs at the interface of a cutting tool and a work-piece during machining, an alternative shear-strain-based criterion, which accounts for the accumulated shear strain over all the slip systems, was employed to model the material-removal process in micro-cutting by Demiral et al [29]. Each modelling approach suffers from some shortcomings, and a comprehensive investigation with regard to the influences of different damage criteria on modelling of material removal in micro-cutting processes is lacking.…”