/FAIL/GENE1
Block Format Keyword Multiple failure models with different combinations with strain rate, thermal or mesh size dependency.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
/FAIL/GENE1/mat_ID/unit_ID | |||||||||
Pmin | Pmax | SigP1_max | Time_max | dtmin | |||||
fct_IDsm | Eps_dot_sm | Sig_max | Sigr | K | |||||
fct_IDps | Eps_dot_ps | Eps_max | Eps_eff | Eps_vol | |||||
Eps_min | Shear | fct_IDg12 | fct_IDg13 | fct_IDe1c | |||||
tab_IDfld | Itab | Eps_dot_fld | Nstep | Ismooth | Istrain | Thinning | |||
Volfrac | P_thickfail | NCS | Tmax | ||||||
fct_IDel | Fscaleel | El_ref |
(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 | (Optional) Unit
identifier. (Integer, maximum 10 digits) |
|
Pmin | Minimum pressure (positive in
compression). (Real) |
|
Pmax | Maximum pressure (positive in
compression). (Real) |
|
SigP1_max | Maximum principal
stress. (Real) |
|
Time_max | Failure time. Default = 1E+20 (Real) |
|
dtmin | Minimum time
step. (Real) |
|
fct_IDsm | Function identifier of the maximum
equivalent stress versus strain rate. (Integer) |
|
Eps_dot_sm | Reference strain rate value for
fct_IDsm Default = 1 (Real) |
|
Sig_max | Ordinate scale factor for
fct_IDsm
or maximum equivalent stress if
fct_IDsm
is not defined. Default = 1, if fct_IDsm is defined (Real) |
|
Sigr | Initial fracture stress for
Tuler-Butcher criterion. (Real) |
|
K | Critical value of the damage
integral for Tuler-Butcher criterion. (Real) |
|
fct_IDps | Maximum principal strain versus
strain rate function identifier. (Integer) |
|
Eps_dot_ps | Reference strain rate value for
fct_IDps. Default = 1 (Real) |
|
Eps_max | Ordinate scale factor for
fct_IDps
or maximum principal strain if
fct_IDps
is not defined. Default = 1, if fct_IDps is defined (Real) |
|
Eps_eff | Maximum effective
strain. (Real) |
|
Eps_vol | Maximum volumetric
strain. (Real) |
|
Eps_min | Minimum principal
strain. (Real) |
|
Shear | Tensorial shear strain (
). Where, is the engineering shear strain at failure. (Real) |
|
fct_IDg12 | Maximum in-plane shear strain
versus element size function
identifier. (Real) |
|
fct_IDg13 | Maximum transversal shear strain
versus element size function
identifier. (Real) |
|
fct_IDe1c | Maximum in-plane major strain
versus element size function
identifier. (Real) |
|
tab_IDfld | Table or function identifier of the
Forming Limit Diagram. (Integer) |
|
Itab | Table dependency type (used only if
tab_IDfld
is a table).
(Integer) |
|
Eps_dot_fld | Reference strain rate value for
tab_IDfld. Default = 1 (Real) |
|
Nstep | Number of cycles for the stress
reduction. Default = 10 (Integer) |
|
Ismooth | Interpolation type (in case of
tabulated yield function).
(Integer) |
|
Istrain | Engineering / True input strain
flag.
(Integer) |
|
Thinning | Thinning failure
value. (Real) |
|
Volfrac |
Damaged volume fraction to reach before the element is deleted (fully-integrated and higher order elements only). Default = 0.5 (Real) |
|
P_thickfail | Ratio of through thickness
integration points that must fail before the under-integrated
element is deleted. 0.0≤ P_thickfail ≤1.0 Default = 1.0 (Real) |
|
NCS | Number of conditions to reach
before the element is deleted. Default = 1 (Integer) |
|
Tmax | Maximum
temperature. (Real) |
|
fct_IDel | Element size scale factor function
identifier for the criterias Pmin, Pmax, SigP1_max, Sig_max,
Sigr, K,
EpsPS_max, Eps_eff,
Eps_vol, Eps_min,
Shear,
tab_IDfld
and Thinning. (Integer) |
|
Fscaleel | Element size function scale factor
for fct_IDel,
tab_IDfld
(Itab=2),
fct_IDg12,
fct_IDg23,
fct_IDg13
and
fct_IDe1c. Default = 1.0 (Real) |
|
El_ref | Reference element size for
fct_IDel,
tab_IDfld
(Itab=2),
fct_IDg12,
fct_IDg23,
fct_IDg13
and
fct_IDe1c. Default = 1.0 (Real) |
|
fail_ID | (Optional) Failure criteria identifier. |
Comments
- Failure criteria is used only if the value is different from 0.
- Failure models including:
- Minimum hydrostatic pressure based failure criteria:
- Maximum hydrostatic pressure based failure criteria:
Where, hydrostatic pressure is computed as:
Note: Hydrostatic pressure is positive in compression. - Maximum principal stress:
- Maximum time ≥ Time_max
- Minimum elementary time step ≤ dtmin (not available with /DT/NODA option).
- Equivalent stress:
- Tuler-Butcher model:
Where, is the principal stress.
- Maximum principal strain:
- Effective strain:
Where, is the deviatoric strain.
- Volumetric strain:
- Minimum principal strain:
- Maximum tensorial shear
strain:
- Mixed-mode fracture criterion:
- if
- if
-
if
Where,
- and
- In-plane major and minor strains
- Through thickness strain
- Characteristic element size
- Forming Limit Diagram (FLD):
- If Itab=1:
- If Itab=2:
Where,
- and
- In-plane major and minor strains
- Characteristic element size
- The stresses are reduced during Nstep cycles before the element deletion
- Minimum thinning based criterion:
- if Thinning > 0, shell element is deleted, if the thickness integration point thinning ≤ -|Thinning|,
- if Thinning < 0, shell element is deleted, if the average thickness thinning ≤ -|Thinning|.
- For solids, element is deleted, if ≤ -|Thinning|.
- Maximum element temperature ≥ Tmax
- Minimum hydrostatic pressure based failure criteria:
- Volfrac is used for fully-integrated and higher order solids and shells. It represents the damaged volume fraction (for example, the sum of damaged integration points of associated volumes) value to reach to trigger the element deletion.
- For under-integrated linear shell elements, deletion is based on the value of P_thickfail. If P_thickfail > 0, the element fails and is deleted when the ratio of through thickness failed integration points equals or exceeds P_thickfail. P_thickfail defined in the failure model overwrite the value defined in the shell property.
- The integration point failure begins when NCS conditions are reached. Then the stresses in the integration points are reduced to zero in Nstep cycles.
- Element size dependency using the following factors:
(1) Where, is the characteristic element size.
- For post-processing results
in ANIM of H3D files, you can use the variable field
DAMA. For /FAIL/GENE1, the damage
variable is computed with the following ratio.
(2) Where,- Number of specified criteria reached by the integration point.
- Number of criteria to reach to trigger integration point failure.