/FAIL/WIERZBICKI

Block Format Keyword Describes the BAO-XUE-Wierzbicki failure model.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/FAIL/WIERZBICKI/mat_ID/unit_ID
C1 C2 C3 C4 m
n Ifail_sh Ifail_so Imoy          
Optional Line
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
fail_ID                  

Definition

Field Contents SI Unit Example
mat_ID Material identifier.

(Integer, maximum 10 digits)

 
unit_ID Unit Identifier.

(Integer, maximum 10 digits)

 
C1 1st parameter.

(Real)

 
C2 2nd parameter.

(Real)

 
C3 3rd parameter.

(Real)

 
C4 4th parameter.

(Real)

 
m 5th parameter.

(Real)

 
n Hardening exponent.

(Real)

 
Ifail_sh Shell failure model flag.
= 1
Shell is deleted, if D = Δ ε p ε ¯ f 1 for one integration point or layer.
= 2
For each integration point, the stress tensor is set to zero, if D = Δ ε p ε ¯ f 1 and shell is deleted, if D = Δ ε p ε ¯ f 1 for all integration points or layer.

(Integer)

 
Ifail_so Brick failure model flag.
= 1
Solid element is deleted, if D = Δ ε p ε ¯ f 1 for one integration point.
= 2
For each integration point, the deviatoric stress tensor vanishes, if D = Δ ε p ε ¯ f 1 .

(Integer)

 
Imoy Failure 3D model (brick) flag.
=0
{ η ¯ = σ m σ V M ξ ¯ = 27 J 3 2 σ V M 3
=1
{ η ¯ = 0 ε p σ m σ V M d ε p ε p ξ ¯ = 0 ε p 27 J 3 2 σ V M 3 d ε p ε p

(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/WIERZBICKI/1/1
#                 C1                  C2                  C3                  C4                   m
                0.87                1.77                0.21                0.56                   2
#                  n  Ifail_sh  Ifail_so      Imoy
                 0.2         0         1         0
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#enddata
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Comments

  1. For ε ¯ f which is used in failure flag is:
    (1)
    ε ¯ f = { ε ¯ max n [ ε ¯ max n ε ¯ min n ] ( 1 ξ ¯ m ) 1 m } 1 n

    fail_wierzbicki
    Figure 1.

    Where,

    ε ¯ max = C 1 e C 2 η ¯

    ε ¯ min = C 3 e C 4 η ¯

    For Brick:
    • If Imoy = 0
    • η ¯ = σ m σ V M ξ ¯ = 27 J 3 2 σ V M 3
    • If Imoy = 1
    • η ¯ = 0 ε p σ m σ V M d ε p ε p ; ξ ¯ = 0 ε p 27 J 3 2 σ V M 3 d ε p ε p
    For Shell:
    • η ¯ = σ m σ V M ; ξ ¯ = 27 2 η ¯ ( η ¯ 2 1 3 )
    Where,
    σ m
    Hydrostatic stress
    σ V M
    von Mises stress
    J 3
    Third invariant deviatoric stress
  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).