Y. Guo et al., Taylor-based nonlocal theory of plasticity: numerical studies of the micro-indentation experiments and crack tip fields, INT J SOL S, 38(42-43), 2001, pp. 7447-7460
Recent advances in strain gradient plasticity have provided a means to quan
titatively characterize the experimentally observed size effect at the micr
on and submicron scales. The introduction of strain gradients in the consti
tutive model has increased the order of governing equations and therefore r
equire additional boundary conditions in some theories of strain gradient p
lasticity. Is it possible to develop a micro-scale plasticity theory that p
reserves the structure of classical plasticity? The Taylor-based nonlocal t
heory (TNT) of plasticity (Int. J. Solids Struct. 38 (2001), 2615) was deve
loped from the Taylor dislocation model for this purpose. We have proposed
a finite element method for TNT plasticity, and have applied it to study mi
cro-indentation experiments. The micro-indentation hardness predicted by TN
T plasticity agrees very well with the indentation hardness data. We have a
lso studied the crack tip field in TNT plasticity, and have found that the
stress level in TNT plasticity is significantly higher than that in classic
al plasticity. This provides an alternative mechanism for cleavage fracture
in ductile materials observed in Elssner et al.'s experiments (Scripta Met
all. Mater. 31 (1994) 1037). (C) 2001 Elsevier Science Ltd. All rights rese
rved.