  This paper presents numerical simulations of metal machining processes with
Eulerian and Total Lagrangian Smoothed Particle Hydrodynamics (SPH). Being a
mesh-free method, SPH can conveniently handle large deformation and material
separation. However, the Eulerian SPH (ESPH) in which the kernel functions are
computed based on the current particle positions suffers from the tensile
instability. The Total Lagrangian SPH (TLSPH) is free of this instability as
the kernel functions are calculated in the reference configurations. In this
work, the metals are modelled using the Johnson-Cook constitutive model, which
can capture strain hardening and thermal softening in metals. The
processing/cutting tools are modelled as rigid bodies, while the metal-tool
contact forces are considered using the standard SPH interaction and the
particle-particle pinball contact in ESPH and TLSPH, respectively. The two
methods are employed to model several cases with impact, pressing, and cutting;
the results are compared with reference experimental and numerical results. It
is found that both the two SPH methods can capture the salient phenomena in
metal processing, e.g. strain localisation, large deformation, and material
separation. However, the TLSPH approach provides a better simulation of strain
localisation and chip morphology. This work shows that the TLSPH method has the
potential to model the metal machining processes efficiently without any
numerical instabilities.
