/FAIL/ORTHSTRAIN

Block Format Keyword An orthotropic strain failure criteria with size effects, strain rate effects, and damage. Available for solid and shell elements.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/FAIL/ORTHSTRAIN/mat_ID/unit_ID
Card 1
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
  P_thickfail         Strdef
Card 2 - Global strain rate dependency parameters
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
ε ˙ 0 Fcut          
Card 3 - Element size scale function
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
fct_IDel Fscaleel El_ref      
Card 4 - Direction 11
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
ε 11 d _ t ε 11 f _ t fct_ID11t ε 11 d _ c ε 11 f _ c fct_ID11c
Card 5 – Direction 22
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
ε 22 d _ t ε 22 f _ t fct_ID22t ε 22 d _ c ε 22 f _ c fct_ID22c
Card 6 - Direction 33 (solids only, leave blank for shells)
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
ε 33 d _ t ε 33 f _ t fct_ID33t ε 33 d _ c ε 33 f _ c fct_ID33c
Card 7 - Direction 12
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
ε 12 d _ t ε 12 f _ t fct_ID12t ε 12 d _ c ε 12 f _ c fct_ID12c
Card 8 - Direction 23 (solids only, leave blank for shells)
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
ε 23 d _ t ε 23 f _ t fct_ID23t ε 23 d _ c ε 23 f _ c fct_ID23c
Card 9 - Direction 31 (solids only, leave blank for shells)
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
ε 31 d _ t ε 31 f _ t fct_ID31t ε 31 d _ c ε 31 f _ c fct_ID31c
Card 10 – Failure model ID (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)

 
P_thickfail Ratio of through thickness integration points that must fail before the element is deleted (shells only).

Default = 1.0 (Real)

 
Strdef Strain measure definition used in failure criterion.
= 1 (Default)
Strain defined by Ismstr flag in property.
= 2
Engineering strain.
= 3
True strain.

(Integer)

 
ε ˙ 0 Reference strain rate.

If ε ˙ ε ˙ 0 , no strain rate effect.

(Real)

[ 1 s ]
Fcut Cutoff frequency for strain rate smoothing.

Default = 1030 (Real)

[Hz]
fct_IDel Element size factor function identifier.

(Integer)

 
Fscaleel Element size function scale factor.

Default = 1.0 (Real)

 
El_ref Reference element size.

Default = 1.0 (Real)

[ m ]
ε 11 d _ t Tensile strain when damage begins in direction 11.  
ε 11 f _ t Tensile strain when the material fails in direction 11.  
fct_ID11t Strain rate factor function in tension, direction 11.  
ε 11 d _ c Compression strain when damage begins in direction 11.  
ε 11 f _ c Compression strain when the material fails in direction 11.  
fct_ID11c Strain rate factor function in compression direction 11.  
ε 22 d _ t Tensile strain when damage begins in direction 22.  
ε 22 f _ t Tensile strain when the material fails in direction 22.  
fct_ID22t Strain rate factor function in tension direction 22.  
ε 22 d _ c Compression strain when damage begins in direction 22.  
ε 22 f _ c Compression strain when the material fails in direction 22.  
fct_ID22c Strain rate factor function in compression direction 22.  
ε 33 d _ t Tensile strain when damage begins in direction 33.  
ε 33 f _ t Tensile strain when the material fails in direction 33.  
fct_ID33t Strain rate function in tension direction 33.  
ε 33 d _ c Compression strain when damage begins in direction 33.  
ε 33 f _ c Compression strain when the material fails in direction 33.  
fct_ID33c Strain rate factor function in compression direction 33.  
ε 12 d _ t Tensile strain when damage begins in direction 12.  
ε 12 f _ t Tensile strain when the material fails in direction 12.  
fct_ID12t Strain rate factor function in tension direction 12.  
ε 12 d _ c Compression strain when damage begins in direction 12.  
ε 12 f _ c Compression strain when the material fails in direction 12.  
fct_ID12c Strain rate factor function in compression direction 12.  
ε 23 d _ t Tensile strain when damage begins in direction 23.  
ε 23 f _ t Tensile strain when the material fails in direction 23.  
fct_ID23t Strain rate factor function in tension direction 23.  
ε 23 d _ c Compression strain when damage begins in direction 23.  
ε 23 f _ c Compression strain when the material fails in direction 23.  
fct_ID23c Strain rate factor function in compression direction 23.  
ε 31 d _ t Tensile strain when damage begins in direction 31.  
ε 31 f _ t Tensile strain when the material fails in direction 31.  
fct_ID31t Strain rate factor function in tension direction 31.  
ε 31 d _ c Compression strain when damage begins in direction 31.  
ε 31 f _ c Compression strain when the material fails in direction 31.  
fct_ID31c Strain rate factor function in compression direction 31.  
fail_ID (Optional) Failure model identifier.

(Integer, maximum 10 digits)

 

Example

#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/UNIT/1
unit for mat
                  kg                  mm                  ms
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#-  2. MATERIALS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/MAT/PLAS_TAB/1/1
DP600 from SSAB Homepage
#        Init. dens.          Ref. dens.
              7.8E-6                   0
#                  E                  Nu           Eps_p_max              Eps_t1              Eps_t2
                 210                  .3                   0                   0                   0
#    Nfunc   Fsmooth               Chard                Fcut               Eps_f
         4         1                   0                  10                   0
#    Ipfun             Fpscale
         0                   0
# Funtions
        14        14        14        14
# Scale factors
                   1                 1.0                 1.2                 1.2
# Strain rates
                1e-6                1e-5                 0.1                 1.0
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FAIL/ORTHSTRAIN/1/1
#                            Pthick_fail                                                      Strdef
                                     0.8
#           Epsp_ref                Fcut        
                 0.0                 0.0
#   fct_el           Fscale_el              El_ref     
         0                   0                   0
#           eps11d_t            eps11f_t   fct_11t            eps11d_c            eps11f_c   fct_11c
                0.01                0.05      1000                 0.1                 0.2      2000        
#           eps22d_t            eps22f_t   fct_22t            eps22d_c            eps22f_c   fct_22c
                0.01                0.05      1001                 0.1                 0.2      2001        
#           eps33d_t            eps33f_t   fct_33t            eps33d_c            eps33f_c   fct_33c
                0.01                0.05      1001                 0.1                 0.2      2001        
#           eps12d_t            eps12f_t   fct_12t            eps12d_c            eps12f_c   fct_12c
                0.01                0.05      1001                 0.1                 0.2      2001        
#           eps23d_t            eps23f_t   fct_23t            eps23d_c            eps23f_c   fct_23c
                0.01                0.05      1001                 0.1                 0.2      2001        
#           eps31d_t            eps31f_t   fct_31t            eps31d_c            eps31f_c   fct_31c
                0.01                0.05      1001                 0.1                 0.2      2001        
#  Fail_ID 
     
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/1000
eps11t
#                  X                   Y
                  0.                   1
                  1.                   1
                 1.2                   1                                                            
              1.0e20                   1                                                            
/FUNCT/2000
eps11c
#                  X                   Y
                  0.                   1
                 .05                   1
                 .06                   1                                                            
              1.0e20                   1                                                            
/FUNCT/1001
bidont
#                  X                   Y
                  0.                   1
              1.0e20                   1                                                            
/FUNCT/2001
bidonc
#                  X                   Y
                  0.                   1
              1.0e20                   1                                                            
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/14
Mat_Curev Quasi-static DOCOL DP 600 (Material from SSAB Homepage 2010)
#                  X                   Y
                   0                .306                                                            
              .00112                .415                                                            
              .00218                .445                                                            
                .003                .461                                                            
              .00404                .474                                                            
              .00517                .489                                                            
              .00613                .498                                                            
               .0071                .505                                                            
              .00806                .512                                                            
              .00901                .522                                                            
               .0102                 .53                                                            
               .0121                .543                                                            
                .013                 .55                                                            
                .014                .555                                                            
                .015                .561                                                            
               .0159                .567                                                            
               .0171                .572                                                            
               .0181                .577                                                            
               .0204                .592                                                            
               .0303                .632                                                            
               .0405                .663                                                            
               .0502                .687                                                            
                 .06                .706                                                            
               .0702                .722                                                            
               .0807                .737                                                            
                 .09                .749                                                            
               .0997                .758                                                            
                .101                .759                                                            
                 .11                .768                                                            
           .15000001                .805                                                            
                  .2                 .84                                                            
           .30000001                  .9                                                            
                  .5                   1                                                            
                   1                1.21                                                            
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#ENDDATA
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Comments

  1. A damage factor is the maximum over time and is calculated for each direction and stress state via:(1)
    d i j l = ( ε i j f _ l ε i j l ) ( ε i j l α ε i j d _ l ε i j f _ l ε i j d _ l )

    Where, the direction is indicated by using the common ij notation and loading state is either compression (l=c) or tension (l=t).

    Where, α = f a c t o r e l f a c t o r r a t e .

    The element size correction factor is:(2)
    f a c t o r e l = F s c a l e e l f e l ( S i z e e l E l _ r e f )
    Where,
    f e l
    Element size correction factor function defined via f c t _ I D e l
    S i z e e l
    Characteristic element size.
    The strain rate factor is:(3)
    facto r rate = f ijl ( ε ˙ ijl ε ˙ 0 ) MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqGqFfpeea0xe9vq=Jb9 vqpeea0xd9q8qiYRWxGi6xij=hbba9q8aq0=yq=He9q8qiLsFr0=vr 0=vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaWGMbGaam yyaiaadogacaWG0bGaam4BaiaadkhadaWgaaWcbaGaamOCaiaadgga caWG0bGaamyzaaqabaGccqGH9aqpciGGMbWaaSbaaSqaaiaadMgaca WGQbGaamiBaaqabaGcdaqadaqaamaalaaabaGafqyTduMbaiaadaWg aaWcbaGaamyAaiaadQgacaWGSbaabeaaaOqaaiqbew7aLzaacaWaaS baaSqaaiaaicdaaeqaaaaaaOGaayjkaiaawMcaaaaa@4EDD@
    Where,
    f i j l
    Strain rate factor function defined via f c t _ I D i j l .
    ε ˙ i j l
    Current (filtered) strain rate in direction ij and load case l.
    ε ˙ 0
    Entered reference strain rate.
  2. Material damage and stress softening are calculated as:
    D max = max ( d i j l ) and σ = ( 1 D max ) σ
    • If 0 < D max < 1 , the stress tensor is reduced.
    • If D max 1 ,the material has failed and the integration point stress tensor is set to zero.
    • D max can be output using options in /ANIM/Eltype/DAMA or /H3D/Eltype/DAMA.
  3. Solid elements are deleted when all integration points reach the failure criterion. Shells are deleted when the sum of thickness of failed layers /integration points in the normal direction is greater than prescribed P_thickfail value.(4)
    l a y e r s t h i c k n e s s f a i l l a y e r s I P > P _ t h i c k f a i l
  4. When the failure model is applied to a material in STACK property, P_thickfail defines a relative thickness of failed integration points, necessary to switch off the corresponding layer. The global element suppression criterion must be defined at the property level.
  5. /FAIL/ORTHSTRAIN should be only associated to materials compatible with orthotropic shell properties. LAW25 is compatible only if it’s used within shell property TYPE51.