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PROP_DAMAGE_JC_MODIFIED

Material properties

Beta command

This command is in the beta stage and the format may change over time.

*PROP_DAMAGE_JC_MODIFIED
"Optional title"
did, erode, noic
$d_1$, $\varepsilon_c$, $\varepsilon_t$, $\alpha$

Parameter definition

Variable
Description
did
Unique damage identification number
erode
Element erosion flag
options:
0 $\rightarrow$ failed element is not eroded
1 $\rightarrow$ failed element is eroded
2 $\rightarrow$ node splitting at failure (crack plane orthogonal to max principal strain)
3 $\rightarrow$ node splitting at failure (crack plane orthogonal to max principal stress)
4 $\rightarrow$ node splitting at failure (Lode angle dependent crack direction)
noic
Flag to turn off cracking along interface between different materials
options:
0 $\rightarrow$ material interface cracks are allowed
1 $\rightarrow$ material interface cracks are not allowed
$d_1$
Damage parameter
$\varepsilon_c$
Damage parameter
$\varepsilon_t$
Damage parameter
$\alpha$
Damage parameter

Description

This is the modified Johnson-Cook model as outlined in Moxnes et al. (2010). The material will fail once the damage parameter, $D$, has evolved from 0 to 1. The damage growth rate is defined as

$\displaystyle{\dot D = \frac{\dot\varepsilon_{eff}^p}{\varepsilon_f}}$

where:

$\displaystyle{\varepsilon_f = d_1 + d_2 \cdot \mathrm{exp}{\left(\frac{d_3 \cdot p}{\sigma_{eff}} \right)}}$

The parameters $d_2$ and $d_3$ are defined as:

$\displaystyle{d_2 = \sqrt{\left( \varepsilon_c + \mathrm{H}(p) \cdot \alpha \cdot \dot{\varepsilon}_{eff}^p\right) \cdot \varepsilon_t}}$
$\displaystyle{d_3 = \frac{3}{2}} \mathrm{ln}\left(\frac{\varepsilon_c + \mathrm{H}(p) \cdot \alpha \cdot \dot{\varepsilon}_{eff}^p}{\varepsilon_t}\right)$

where $\mathrm{H}(p)$ is the Heaviside step function, defined as:

$\mathrm{H}(p) = \left\{ \begin{array}{cc} 0 & p \lt 0 \\ 1 & p \geq 0 \end{array} \right. $

The pressure, $p$, is defined as:

$p = -(\sigma_{xx} + \sigma_{yy} + \sigma_{zz})/3$

Reference

J. F. Moxnes, J. A. Teland, S. Skriudalen, S. M. Bergsrud, L. Sundem-Eriksen and H. Fykse, Development of material models for semi-brittle materials like tungsten carbide, Norwegian Defence Research Establishment (FFI), FFI-rapport 2010/02225, 2010.