| Abaqus Keywords Reference Guide |
|
| How to find keyword examples |
| Abaqus Keywords Reference Guide |
|
| How to find keyword examples |
This option is used to define material constants for a general hyperelastic material.
Products: Abaqus/Standard Abaqus/Explicit Abaqus/CAE
Type: Model data
Level: Model
Abaqus/CAE: Property module
Include this parameter to use the Arruda-Boyce model, also known as the eight-chain model.
Include this parameter to use the Marlow model.
Include this parameter to use the Mooney-Rivlin model. This method is equivalent to using the POLYNOMIAL parameter with N=1.
Include this parameter to use the neo-Hookean model. This method is equivalent to using the REDUCED POLYNOMIAL parameter with N=1.
Include this parameter to use the Ogden strain energy potential.
Include this parameter to use the polynomial strain energy potential. This method is the default method of defining the strain energy potential.
Include this parameter to use the reduced polynomial strain energy potential. This method is equivalent to using the POLYNOMIAL parameter with 
for 
.
This parameter applies only to Abaqus/Standard analyses.
Include this parameter if the derivatives of the strain energy potential with respect to the strain invariants are defined in user subroutine UHYPER.
Include this parameter to use the Van der Waals model, also known as the Kilian model.
Include this parameter to use the Yeoh model. This method is equivalent to using the REDUCED POLYNOMIAL parameter with N=3.
This parameter can be used only when both the VAN DER WAALS and TEST DATA INPUT parameters are used; it defines the value of 
while the other coefficients of the Van der Waals model are fitted from the test data given by the user. If this parameter is omitted, will be determined from a nonlinear, least-squares fit of the test data. Allowable values of BETA are 
. It is recommended to set = 0 if only one type of test data is available.
This parameter is applicable only when the *HYPERELASTIC option is used in conjunction with the *VISCOELASTIC or the *HYSTERESIS option.
Set MODULI=INSTANTANEOUS to indicate that the hyperelastic material constants define the instantaneous behavior. This parameter value is not available for frequency domain viscoelasticity in an Abaqus/Standard analysis. This is the only option available if the hyperelastic material is defined in user subroutine UHYPER.
Set MODULI=LONG TERM to indicate that the hyperelastic material constants define the long-term behavior. This option is not available when user subroutine UHYPER is used to define the hyperelastic material. It is the default for all other hyperelastic models.
This parameter can be used only with the OGDEN, POLYNOMIAL, and REDUCED POLYNOMIAL parameters. Include this parameter to define the order of the strain energy potential. The default is N=1.
If the TEST DATA INPUT parameter is used, the parameter N can take only the values 1 or 2 for the POLYNOMIAL form and up to 6 for the OGDEN and REDUCED POLYNOMIAL forms.
If the TEST DATA INPUT parameter is omitted, the maximum value of N is 6 for either form.
Set this parameter equal to the Poisson's ratio, 
, to account for compressibility. This parameter cannot be used if the material coefficients are specified directly or if volumetric behavior is defined by entering nonzero values for 
on the data line or by specifying the *VOLUMETRIC TEST DATA option. In addition, this parameter cannot be used for the Marlow model if the nominal lateral strains are specified on the *UNIAXIAL TEST DATA, *BIAXIAL TEST DATA, or *PLANAR TEST DATA option.
This parameter applies only to Abaqus/Standard analyses.
This parameter can be used only if the USER parameter is specified. Set this parameter equal to the number of property values needed as data in user subroutine UHYPER. The default value is 0.
Include this parameter if the material constants are to be computed by Abaqus from data taken from simple tests on a material specimen.
If this parameter is omitted, the material constants must be given directly on the data lines. This parameter is not relevant for the Marlow model, in which case the test data must be specified.
Alternative options for specifying test data rather than specifying relevant material constants on the data lines of the *HYPERELASTIC option are applicable to all hyperelastic material models except the user-defined model. No data lines are used with the *HYPERELASTIC option when the MARLOW or TEST DATA INPUT parameter is specified. In this case the test data are specified with the *BIAXIAL TEST DATA, *PLANAR TEST DATA, *UNIAXIAL TEST DATA, and *VOLUMETRIC TEST DATA options.
First line:
.
.
.
Temperature.
Repeat this data line as often as necessary to define the material constants as a function of temperature.
First line:
.
.
.
Temperature.
Repeat this data line as often as necessary to define the material constants as a function of temperature.
First line:
.
.
Temperature.
Repeat this data line as often as necessary to define the material constants as a function of temperature.
First line if N=1:
.
.
.
Temperature.
Repeat this data line as often as necessary to define the material constants as a function of temperature.
First line if N=2:
.
.
.
.
.
.
Temperature.
Repeat this data line as often as necessary to define the material constants as a function of temperature.
First line if N=3:
.
.
.
.
.
.
.
.
Second line if N=3:
.
Temperature.
Repeat this pair of data lines as often as necessary to define the material constants as a function of temperature.
Data lines for higher values of N (up to 6):
The data lines for higher values of N follow the same pattern. First, give the 
and 
for i from 1 to N. Then, give the N coefficients . Finally, give the temperature. Exactly eight data values should be given on each line.
First line if N=1:
.
.
.
Temperature.
Repeat this data line as often as necessary to define the material constants as a function of temperature.
First line if N=2:
.
.
.
.
.
.
.
Temperature.
Repeat this data line as often as necessary to define the material constants as a function of temperature.
First line if N=3:
.
.
.
.
.
.
.
.
Second line if N=3:
.
.
.
.
Temperature.
Repeat this pair of data lines as often as necessary to define the material constants as a function of temperature.
Data lines for higher values of N (up to 6):
The data lines for higher values of N follow the same pattern. For each value of 
from 1 to N, give the 
, with i decreasing from to zero and j increasing from zero to . Then, give the N coefficients . Finally, give the temperature. Exactly eight data values should be given on each line.
First line if N=1:
.
.
Temperature.
Repeat this data line as often as necessary to define the material constants as a function of temperature.
First line if N=2:
.
.
.
.
Temperature.
Repeat this data line as often as necessary to define the material constants as a function of temperature.
First line if N=3:
.
.
.
.
.
.
Temperature.
Repeat this data line as often as necessary to define the material constants as a function of temperature.
Data lines for higher values of N (up to 6):
The data lines for the higher values of N follow the same pattern. First, give the 
for 
from 
to 
. Then, give the N coefficients . Finally, give the temperature. Exactly eight data values should be given on each line.
No data lines are needed if the PROPERTIES parameter is omitted or set to 0. Otherwise, first line:
Give the material properties, eight per line. If this option is used in conjunction with the *VISCOELASTIC or *HYSTERESIS option, the material properties must define the instantaneous behavior. If this option is used in conjunction with the *MULLINS EFFECT option, the material properties must define the primary response.
Repeat this data line as often as necessary to define the material properties.
.