MATVP
Bulk Data Entry Defines material properties for nonlinear creep materials.
Format A: For Power law-based definition (CTYPE=TIMEC, TIMET, HYPERB)
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
MATVP | MID | CTYPE | A | n | m | B | R | dH | |
thetaZ |
Format B: For material parameter calibration from test data (CTYPE=TEST)
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
MATVP | MID | TEST | TID | SIG | ALB | AUB | nLB | nUB | |
mLB | mUB |
Format C: For Anand material model (CTYPE=ANAND)
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
MATVP | MID | ANAND | A | n | m | R | dH | ||
thetaZ | a | A0 | A1 | A2 | A3 | A4 | |||
S1 | S2 | S3 |
Format D: For Darveaux material model (CTYPE=DARVEAU)
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
MATVP | MID | DARVEAU | n | R | dH | ||||
thetaZ | B |
Example A
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
MATVP | 101 | STRAIN | 3.28e-11 | 3.15 | -0.2 |
Example B
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
MATVP | 102 | TEST | 1001 | 39.3 |
Definitions
Field | Contents | SI Unit Example |
---|---|---|
MID | Unique material identification number.
No default (Integer > 0) |
|
CTYPE | Specifies the creep material model
type.
|
|
A | Material parameter. No default (Real > 0.0) |
|
Material parameter. No default (Real > 0.0) |
||
n | Material parameter. No default (Real > 0.0) |
|
m | Material parameter. No default (-1.0 ≤ Real ≤ 0.0) for CTYPE = STRAIN, TIMEC, TIMET No default (Real) for CTYPE=ANAND |
|
B | Material parameter. 8 No default (Real > 0.0) |
|
Material parameter. No default (Real > 0.0) |
||
Material parameter. No default (Real > 0.0) |
||
R | Universal gas constant. 8 No default (Real > 0.0) |
|
dH | Activation energy. 8 No default (Real > 0.0) |
|
thetaZ | Absolute zero temperature. Default = 0.0 (Real) |
|
Material parameter. No default (Real) |
||
a | Material parameter. No default (Real) |
|
Material parameter. No default (Real > 0.0) |
||
A0 | Material parameter. No default (Real) |
|
A1 | Material parameter. Default = 0.0 (Real) |
|
A2 | Material parameter. Default = 0.0 (Real) |
|
A3 | Material parameter. Default = 0.0 (Real) |
|
A4 | Material parameter. Default = 0.0 (Real) |
|
S1 | Material parameter. No default (Real) |
|
S2 | Material parameter. Default = 0.0 (Real) |
|
S3 | Material parameter. Default = 0.0 (Real) |
|
TID | Table identification number of a
TABLES1 entry containing experimental test data. 9 In the TABLES1 definition,
(Integer > 0) |
|
SIG | von Mises stress of the experimental
test data. No default (Real ≥ 0.0) |
|
ALB | Lower bound for the material parameter
A. 10 No default (Real > 0.0) |
|
AUB | Upper bound for the material parameter
A. 10 No default (Real > 0.0) |
|
nLB | Lower bound for the material parameter
n. Default = 0.0 (Real ≧ 0.0) |
|
nUB | Upper bound for the material parameter
n. Default = 6.0 (Real > 0.0) |
|
mLB | Lower bound for the material parameter
m. Default = -1.0 (-1 ≦ Real < 0.0) |
|
mUB | Upper bound for the material parameter
m. Default = 0.0 (-1 < Real ≦ 0.0) |
Comments
- Support information for MATVP is:
- Analysis types: Nonlinear static/transient for both small/large displacement types.
- Elements: CHEXA, CTETRA, CPENTA, CPYRA.
- Specifying a MAT1 and a MATVP Bulk Data Entry with the same MID allows modeling creep material. Specifying a MAT1, a MATS1 and a MATVP Bulk Data Entry with the same MID can model a creep material with plasticity.
- You can choose explicit or implicit time integration for creep materials by using the TINT field of the VISCO card.
- The formulation for different material models
are as follows:STRAIN hardening formulation:
(1) TIME hardening formulation:(2) Where,- Equivalent creep strain rate
- Equivalent deviatoric stress
- Total time
HYPERB material model formulation:(3) Where,- and
- The current and absolute zero temperatures, respectively.
Anand material model formulation:(4) (5) (6) (7) (8) Where,- Deformation resistance
- Initial deformation resistance
Darveaux material model formulation:(9) - The units of various CTYPE
material parameters:
- STRAIN, TIMEC, TIMET
- Material Parameter
- Units
- A
- HYPERB
- Material Parameter
- Units
- A
- B
- dH
- R
- thetaZ
- ANAND
- Material Parameter
- Units
- A
- B
- dH
- R
- thetaZ
- A0
- S1
- S2
- S3
- A1
- A2
- A3
- A4
- DARVEAU
- Material Parameter
- Units
- dH
- R
Where,- Force
- Length
- Time
Consider switching to another set of units if the values are too small. All other material parameters not mentioned above are dimensionless.
- STRAIN, TIMEC, TIMET
- A VISCO Subcase Entry is mandatory to conduct creep material analysis in a particular subcase.
- If CNTNLSUB is used with the
time hardening form:
- TIMEC indicates the accumulative time, only from the subcases with the VISCO entry.
- TIMET indicates the accumulative time from all the connected subcases.
For example, if there are 4 subcases – 1, 2, 3 and 5, where only Subcases 1, 3, and 5 are connected by CNTNLSUB.
If subcases 1 and 5 have VISCO entry while Subcase 3 does not have the VISCO entry, then:- TIMEC will indicate the accumulative time from Subcases 1 and 5 only.
- TIMET will indicate the accumulative time from Subcases 1, 3 and 5.
If CNTNLSUB is not used, then both TIMEC and TIMET have the same effect of denoting the time for a specific subcase (only for subcases with the VISCO entry).
- The material parameters must be specified
according to the chosen creep law. For example, the parameter B is used in both Hyperbolic
Sine and the Darveaux models, but their meanings are different.
For the Anand model, if the ratio dH/R is the only available unit, set R as 1.0 and use dH/R as the value of dH. If and are known, set them as the values of and and set all other and as zeroes.
- Format B can be used for a basic material parameter calibration functionality based on experimental creep test data. The calibration is based on a time hardening formulation. The upper and lower bounds can be used for searching the suitable parameter values during the calibration process.
- There are no default values for
ALB and AUB. The following are example values:
- ALB=1.0e-25, AUB=1.0e-20
- ALB=1.0e-20, AUB=1.0e-15
- ALB=1.0e-15, AUB=1.0e-10
- ALB=1.0e-10, AUB=1.0e-5
- ALB=1.0e-5, AUB=1.0