*VISCOELASTIC
Optional parameters when test data are given to define time domain viscoelasticitywith
TIME=CREEP TEST DATA or TIME=RELAXATIONTEST DATA or when test data are given to
define frequency domain viscoelasticity with FREQUENCY=PRONY,FREQUENCY=CREEP TEST
DATA, or FREQUENCY=RELAXATIONTEST DATA:
ERRTOL
Set this parameter equal to the allowable average root-mean-squareerror of the data points in the
least-squares fit. The default is 0.01 (1%).
NMAX
Set this parameter equal to the maximum number of term s Nin the Prony series. ABAQUS w ill
perform the least-squares fit from to NMAX until convergence is achieved for the
lowest Nwith respect to ERRTOL.The default and maximum value is 13.
Data line to define continuum material propertiesfor FREQUENCY=FORMULA:
First (and only) line:
1. Real part of .
2. Imaginary partof .
3. Valueof a.
4. Realpart of . Ifthe materi al is incompressible, this value is ignored.
5. Imaginarypart of . If the material is incom pressible, this value is ignored.
6. Valueof b. Ifthe material is incompressible, this value is ignored.
Data lines to define continuum material properties forFREQUENCY=TABULAR without the
PRELOAD parameter or for TIME=FREQUENCYDATA:
First line:
1. Real part of .
2. Imaginarypart of .
3. Realpart of .If the material is incompressible, t his value is ignored.
4. Imaginarypart of . Ifthe mater ial is incompressible, this value
is ignored.
5. Frequency,f, in cycles per time.
Repeat this data line as often as necessary to define the dissipativepar t of the materialbehavior.
Data lines to define continuum material properties for FREQUENCY=TABULAR,
PRELOAD=UNIAXIAL:
First line:
1. Uniaxialloss modulus.
2. Uniaxial storage modulus.
21.4–3
ABAQUS Version 6.1 Module: ID:
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