Viscoelastic object

The Viscoelastic object specifies dissipative behavior for use with elasticity.

The following topics are discussed:

Access

import material
mdb.models[name].materials[name].viscoelastic
import odbMaterial
session.odbs[name].materials[name].viscoelastic

Viscoelastic(...)

This method creates a Viscoelastic object.

Path

mdb.models[name].materials[name].Viscoelastic
session.odbs[name].materials[name].Viscoelastic

Required arguments

domain

A SymbolicConstant specifying the domain definition. Possible values are:

  • FREQUENCY, specifying a frequency domain. This domain is only available for an Abaqus/Standard analysis.

  • TIME, specifying a time domain.

table

A sequence of sequences of Floats specifying the items described below.

Optional arguments

frequency

A SymbolicConstant specifying the frequency domain definition. This argument is required only when domain=FREQUENCY. Possible values are FORMULA, TABULAR, PRONY, CREEP_TEST_DATA, and RELAXATION_TEST_DATA. The default value is FORMULA.

type

A SymbolicConstant specifying the type. This argument is required only when domain=FREQUENCY and frequency=TABULAR. Possible values are ISOTROPIC and TRACTION. The default value is ISOTROPIC.

preload

A SymbolicConstant specifying the preload. This argument is required only when domain=FREQUENCY and frequency=TABULAR. Possible values are NONE, UNIAXIAL, VOLUMETRIC, and UNIAXIAL_VOLUMETRIC. The default value is NONE.

time

A SymbolicConstant specifying the time domain definition. This argument is required only when domain=TIME. Possible values are PRONY, CREEP_TEST_DATA, RELAXATION_TEST_DATA, and FREQUENCY_DATA. The default value is PRONY.

errtol

A Float specifying the allowable average root-mean-square error of the data points in the least-squares fit. The Float values correspond to percentages; for example, 0.01 is 1%. The default value is 0.01.

This argument is valid only when time=CREEP_TEST_DATA, RELAXATION_TEST_DATA or FREQUENCY_DATA; or only when frequency=CREEP_TEST_DATA or RELAXATION_TEST_DATA.

nmax

An Int specifying the maximum number of terms N in the Prony series. The maximum value is 13. The default value is 13.

This argument is valid only when time=CREEP_TEST_DATA, RELAXATION_TEST_DATA or FREQUENCY_DATA; or only when frequency=CREEP_TEST_DATA or RELAXATION_TEST_DATA.

volumetricTable

A sequence of sequences of Floats specifying the items described below. The default value is an empty sequence.

Table data

If frequency=FORMULA, the table data for table specify the following:

  • Real part of g1* (g*⁢(ω)=g1*⁢f-a).

  • Imaginary part of g1*.

  • Value of a.

  • Real part of k1* (k*⁢(ω)=k1*⁢f-b). If the material is incompressible, this value is ignored.

  • Imaginary part of k1*. If the material is incompressible, this value is ignored.

  • Value of b. If the material is incompressible, this value is ignored.

If frequency=TABULAR and type=ISOTROPIC and preload=NONE, or time=FREQUENCY_DATA the table data for table specify the following:

  • Real part of ω⁢g* (ω⁢ℜ⁡(g*)=Gℓ/G∞).

  • Imaginary part of ω⁢g* (ωℑ(g*)=1-Gs/G∞).

  • Real part of ω⁢k* (ω⁢ℜ⁡(k*)=Kℓ/K∞). If the material is incompressible, this value is ignored.

  • Imaginary part of ω⁢k* (ω⁢ℑ⁡(k*)=1-Ks/K∞). If the material is incompressible, this value is ignored.

  • Frequency f in cycles per time.

If frequency=TABULAR and type=ISOTROPIC and preload=UNIAXIAL the table data for table specify the following:

  • Loss modulus.

  • Storage modulus.

  • Frequency.

  • Uniaxial strain.

If frequency=TABULAR and type=TRACTION and preload=NONE the table data for table specify the following:

  • Normalized loss modulus.

  • Normalized shear modulus.

  • Frequency.

If frequency=TABULAR and type=TRACTION and preload=UNIAXIAL or preload=UNIAXIAL_VOLUMETRIC the table data for table specify the following:

  • Loss modulus.

  • Storage modulus.

  • Frequency.

  • Closure.

If time=PRONY or frequency=PRONY, the table data for table specify the following:

  • g¯1P, the modulus ratio in the first term in the Prony series expansion of the shear relaxation modulus.

  • k¯1P, the modulus ratio in the first term in the Prony series expansion of the bulk relaxation modulus.

  • τ1, the relaxation time for the first term in the Prony series expansion.

If frequency=TABULAR and type=ISOTROPIC and preload=VOLUMETRIC or preload=UNIAXIAL_VOLUMETRIC the table data for volumetricTable specify the following:

  • Loss modulus.

  • Storage modulus.

  • Frequency.

  • Volume ratio.

Return value

A Viscoelastic object.

Exceptions

RangeError.

setValues(...)

This method modifies the Viscoelastic object.

Required arguments

None.

Optional arguments

The optional arguments to setValues are the same as the arguments to the Viscoelastic method.

Return value

None.

Exceptions

RangeError.

Members

The Viscoelastic object has members with the same names and descriptions as the arguments to the Viscoelastic method.

In addition, the Viscoelastic object can have the following members:

combinedTestData

A CombinedTestData object.

shearTestData

A ShearTestData object.

trs

A Trs object.

volumetricTestData

A VolumetricTestData object.

Corresponding analysis keywords