Johnson-Cook Damage

The model assumes that the equivalent plastic strain at the onset of damage is a function of stress triaxiality and strain rate. The Johnson-Cook criterion can be used in conjunction with the von Mises, Johnson-Cook, and Hill plasticity models, including equation of state.

{\bar{ε}}_{D}^{p l} = [d_{1} + d_{2} \exp (- d_{3} η)] [1 + d_{4} \ln (\frac{{\overset{\dot{¯}}{ε}}_{D}^{p l}}{{\dot{ε}}_{0}})] (1 + d_{5} \hat{θ}),

where $\hat{θ}$ is the nondimensional temperature defined as


Input Data	Description
D1 through D5	Failure parameters $d_{1}$ - $d_{5}$ .
Melting temperature	$θ_{m e l t}$
Transition temperature	$θ_{t r a n s i t i o n}$
Reference strain rate	${\dot{ε}}_{0}$
Use damage evolution	Damage evolution defines how the material degrades after one or more damage initiation criteria are met. Select the check box, and specify settings in the Damage Evolution group box; these settings are described in Damage Evolution.