/FAIL/XFEM_JOHNS (Obsolete)
Block Format Keyword Describes a XFEM (eXtended Finite Element Method) failure model.
Format
(1)  (2)  (3)  (4)  (5)  (6)  (7)  (8)  (9)  (10) 

/FAIL/XFEM_JOHNS/mat_ID/unit_ID  
D_{1}  D_{2}  D_{3}  D_{4}  D_{5}  
${\dot{\epsilon}}_{0}$  I_{fail_sh} 
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) 

D_{1}  1^{st}
parameter (Real) 

D_{2}  2^{nd}
parameter (Real) 

D_{3}  3^{rd}
parameter (Real) 

D_{4}  4^{th}
parameter (Real) 

D_{5}  5^{th}
parameter (Real) 

${\dot{\epsilon}}_{0}$  Reference strain
rate (Real) 
$\left[\frac{\text{1}}{\text{s}}\right]$ 
I_{fail_sh}  Shell failure flag
(Integer) 

fail_ID  (Optional) Failure
criteria identifier 4 (Integer, maximum 10 digits) 
Example (Steel)
#RADIOSS STARTER
#12345678910
/UNIT/1
unit for mat
# MUNIT LUNIT TUNIT
Mg mm s
#12345678910
# 1. MATERIALS:
#12345678910
/MAT/PLAS_JOHNS/1/1
Steel
# RHO_I
7.8E9
# E Nu
210000 .3
# a b n EPS_p_max SIG_max0
270 450 .6 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/JOHNSON/1/1
# D1 D2 D3 D4 D5
0.11 0.08 1.5 0 0
# EPS_0 Ifail_sh Ifail_so Dadv Ixfem
1 1 1 0.5 1
#12345678910
#enddata
#12345678910
Comments
 This failure model is available for Shell only.
 The parameters are
used in the stressstrain relationship:
(1) $${\epsilon}_{f}=\left[{D}_{1}+{D}_{2}\mathrm{exp}\left({D}_{3}{\sigma}^{*}\right)\right]\hspace{0.17em}\left[1+{D}_{4}\mathit{In}\left({\dot{\epsilon}}^{*}\right)\right]\hspace{0.17em}\left[1+{D}_{5}{T}^{*}\right]$$Where,
${\sigma}^{*}=\frac{{\sigma}_{m}}{{\sigma}_{VM}}$ ; ${\dot{\epsilon}}^{*}=\frac{\dot{\epsilon}}{{\dot{\epsilon}}_{0}}$
T* is computed in the material law, if this one is thermo plastic, like /MAT/LAW4 (HYD_JCOOK).
 Current known
limitations are:
 /PARITH/ON does not ensure results repeatability, if SPMD > 1; it works in SMP parallel mode only.
 XFEM is currently NOT compatible with either /ANIM/VECT or with /PARITH/OFF.
 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).