Crack Tip Shielding from a Plastic ‘Inclusion’
This paper presents a very brief overview of the philosophy underlying a plastic inclusion approach to defining the boundary stresses imposed on the applied elastic stress or displacement field by the plastic deformation attendant on crack growth in a ductile material. It leads to two new fracture mechanics parameters, KR and KS. KR defines a retardation component arising from wake contact and the Poisson’s contraction associated with the plastic zone, whilst KS describes a compatibility-induced component arising from shear at the elastic-plastic interface. These additional components imply that KF is not directly comparable with KI, as it describes the net driving force on the crack from the applied load.
M. N. James et al., "Crack Tip Shielding from a Plastic ‘Inclusion’", Key Engineering Materials, Vol. 465, pp. 1-8, 2011