# /FAIL/WILKINS

Block Format Keyword Describes the Wilkins failure model.

## Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/FAIL/WILKINS/mat_ID/unit_ID
α $\beta$ ${P}_{\mathrm{lim}}$ ${D}_{f}$ Ifail_sh Ifail_so
Optional Line
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
fail_ID

## Definitions

Field Contents SI Unit Example
mat_ID Material identifier.

(Integer, maximum 10 digits)

unit_ID Unit Identifier.

(Integer, maximum 10 digits)

α Hydrostatic pressure exponent.

(Real)

$\beta$ Deviatoric coefficient.

(Real)

${P}_{\mathrm{lim}}$ Hydrostatic pressure limit.

(Real)

$\left[\text{Pa}\right]$
${D}_{f}$ Critical damage.

(Real)

Ifail_sh Shell failure flag.
= 1
Shell is deleted, if ${D}_{c}\ge {D}_{f}$ for one integration point or layer.
= 2
For each integration point, the stress tensor is set to zero, if ${D}_{c}\ge {D}_{f}$ and shell is deleted, if ${D}_{c}\ge {D}_{f}$ for all integration points or layers.

(Integer)

Ifail_so Solid failure flag.
= 1
Solid is deleted, if ${D}_{c}\ge {D}_{f}$ for one integration point.
= 2
For each integration point, the deviatoric stress tensor vanishes, if ${D}_{c}\ge {D}_{f}$ .

(Integer)

fail_ID Failure criteria identifier. 2

(Integer, maximum 10 digits)

## Example (Metal)

#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/UNIT/1
unit for mat
#              MUNIT               LUNIT               TUNIT
Mg                  mm                   s
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#-  1. MATERIALS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/MAT/PLAS_JOHNS/1/1
Metal
#              RHO_I
2.8E-9                   0
#                  E                  Nu
60000                  .3
#                  a                   b                   n           EPS_p_max            SIG_max0
370                 190                  .4                   0                   0
#                  c           EPS_DOT_0       ICC   Fsmooth               F_cut               Chard
0                   0         0         0                   0                   0
#                  m              T_melt              rhoC_p                 T_r
0                   0                   0                   0
/FAIL/WILKINS/1/1
#              Alpha                Beta                Plim                  Df  Ifail_sh  Ifail_so
1.8                 .75                 750                 0.3         1         0
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#enddata
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

1. The cumulative damage is:

${D}_{c}=\int {W}_{1}{W}_{2}d{\overline{\epsilon }}_{p}$

Where,

${W}_{1}={\left(\frac{1}{1+aP}\right)}^{\alpha }$

$a=-\frac{1}{{P}_{\mathrm{lim}}}$

Where,
P
Hydro pressure

$P=-\frac{1}{3}\sum _{j=1}^{3}{\sigma }_{j}{}_{j}$

${W}_{2}={\left(2-A\right)}^{\beta }\text{\hspace{0.17em}}$

$A=\mathrm{max}\left(\frac{{s}_{2}}{{s}_{1}},\frac{{s}_{2}}{{s}_{3}}\right),\text{\hspace{0.17em}}{s}_{1}\ge {s}_{2}\ge {s}_{3}$

Where, ${s}_{1},{s}_{2},{s}_{3}$ are the deviatoric stresses.

2. The fail_ID is used with /STATE/BRICK/FAIL and /INIBRI/FAIL. There is no default value. If the line is blank, no value will be output for failure model variables in the /INIBRI/FAIL (written in .sta file with /STATE/BRICK/FAIL option).