We have always modelled crack propagation under monotonic/static loading in metals assuming isotropic hardening. However, we show that anisotropic/kinematic hardening effects play a significant role due to non-proportional straining with crack advance; the isotropic hardening idealization leads to steady state fracture toughness predictions that could be 50% lower. I hope that some of you find this work interesting.
Emilio Martínez-Pañeda, Norman A. Fleck. Crack Growth Resistance in Metallic Alloys: The Role of Isotropic Versus Kinematic Hardening.