*VISCOELASTIC

Data line to define continuum material properties for FREQUENCY=FORMULA

First (and only) line

1. Real part of $g_1^{*}$. $\left(g^{*}\left(\omega \right)=g_1^{*}{f}^{-a}\right)$

2. Imaginary part of $g_1^{*}$.

3. Value of a.

4. Real part of $k_1^{*}$. $\left(k^{*}\left(\omega \right)=k_1^{*}{f}^{-b}\right)$ If the material is incompressible, this value is ignored.

5. Imaginary part of $k_1^{*}$. If the material is incompressible, this value is ignored.

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

Data lines to define continuum material properties for FREQUENCY=TABULAR without the PRELOAD parameter or for TIME=FREQUENCY DATA

First line

1. Real part of $\omega g^{*}$. $\left(\omega \mathrm{\Re }\left(g^{*}\right)=G_{\mathrm{\ell }}/G_{\mathrm{\infty }}\right)$

2. Imaginary part of $\omega g^{*}$. $(\omega \mathrm{\Im }(g*)=1-G_s/G_{\mathrm{\infty }})$

3. Real part of $\omega k^{*}$. $\left(\omega \mathrm{\Re }\left(k^{*}\right)={\mathrm{K}}_{\mathrm{\ell }}/{\mathrm{K}}_{\mathrm{\infty }}\right)$ If the material is incompressible, this value is ignored.

4. Imaginary part of $\omega k^{*}$. $\left(\omega \mathrm{\Im }\left(k^{*}\right)=1-{\mathrm{K}}_s/{\mathrm{K}}_{\mathrm{\infty }}\right)$ If the material is incompressible, this value is ignored.

5. Frequency, f, in cycles per time.

Repeat this data line as often as necessary to define the dissipative part of the material behavior.

Data lines to define continuum material properties for FREQUENCY=TABULAR, PRELOAD=UNIAXIAL

First line

1. Uniaxial loss modulus.

2. Uniaxial storage modulus.

3. Frequency, f, in cycles per time.

4. Uniaxial nominal strain (defines the level of uniaxial preload).

Repeat this data line as often as necessary to define the uniaxial loss and storage moduli as functions of frequency and preload.

Data lines to define continuum material properties for FREQUENCY=TABULAR, PRELOAD=VOLUMETRIC

First line

1. Bulk loss modulus.

2. Bulk storage modulus.

3. Frequency, f, in cycles per time.

4. Volume ratio, J (current volume/original volume; defines the level of volumetric preload).

Repeat this data line as often as necessary to define the bulk loss and storage moduli as functions of frequency and preload.

Data lines to specify continuum material properties with the Prony series parameters directly using TIME=PRONY or FREQUENCY=PRONY

First line

1. ${\overline{g}}_1^P$, the modulus ratio in the first term in the Prony series expansion of the shear relaxation modulus.

2. ${\overline{k}}_1^P$, the modulus ratio in the first term in the Prony series expansion of the bulk relaxation modulus.

3. ${\tau }_1$, the relaxation time for the first term in the Prony series expansion.

Repeat this data line as often as necessary to define the second, third, etc. terms in the Prony series. There is no restriction on the number of terms in the Prony series.

Data lines to define viscoelastic properties for cohesive elements with elastic traction-separation behavior using TIME=PRONY

First line

1. ${\overline{g}}_1^P$, the modulus ratio in the first term in the Prony series expansion of the shear traction relaxation modulus.

2. ${\overline{k}}_1^P$, the modulus ratio in the first term in the Prony series expansion of the normal traction relaxation modulus.

3. ${\tau }_1$, the relaxation time for the first term in the Prony series expansion.

Repeat this data line as often as necessary to define the second, third, etc. terms in the Prony series. There is no restriction on the number of terms in the Prony series.

Data lines to define viscoelastic properties for cohesive elements with elastic traction-separation behavior using TIME=FREQUENCY DATA

First line

1. Real part of $\omega g^{*}$. $\left(\omega \mathrm{\Re }\left(g^{*}\right)=G_{\mathrm{\ell }}/G_{\mathrm{\infty }}\right)$

2. Imaginary part of $\omega g^{*}$. $(\omega \mathrm{\Im }(g*)=1-G_s/G_{\mathrm{\infty }})$

3. Real part of $\omega k^{*}$. $\left(\omega \mathrm{\Re }\left(k^{*}\right)={\mathrm{K}}_{\mathrm{\ell }}/{\mathrm{K}}_{\mathrm{\infty }}\right)$

4. Imaginary part of $\omega k^{*}$. $\left(\omega \mathrm{\Im }\left(k^{*}\right)=1-{\mathrm{K}}_s/{\mathrm{K}}_{\mathrm{\infty }}\right)$

5. Frequency, f, in cycles per time.

Repeat this data line as often as necessary to define the dissipative part of the material behavior.

To specify viscoelastic behavior via test data

No data lines are used with this option when either TIME=CREEP TEST DATA or TIME=RELAXATION TEST DATA is specified. The test data are given by the SHEAR TEST DATA and the VOLUMETRIC TEST DATA options or by the COMBINED TEST DATA option.

Data lines to define effective thickness-direction gasket properties for PRELOAD=UNIAXIAL

First line

1. Effective thickness-direction loss modulus.

2. Effective thickness-direction storage modulus.

3. Frequency, f, in cycles per time.

4. Closure (defines the level of preload).

Repeat this data line as often as necessary to define the effective thickness-direction gasket loss and storage moduli as functions of frequency and preload.

Data lines to define effective thickness-direction gasket properties if PRELOAD=UNIAXIAL is not included

First line

1. Real part of $\omega k^{*}$. $\left(\omega \mathrm{\Re }\left(k^{*}\right)=k_{\mathrm{\ell }}/k_{\mathrm{\infty }}\right)$, where $k^{*}$ represents the complex effective thickness direction dynamic stiffness.

2. Imaginary part of $\omega k^{*}$. $(\omega \mathrm{\Im }(k*)=1-k_s/k_{\mathrm{\infty }})$, where $k^{*}$ represents the complex effective thickness direction dynamic stiffness.

3. Frequency, f, in cycles per time.

Repeat this data line as often as necessary to define the normalized effective thickness-direction gasket loss and storage moduli as functions of frequency.

Data lines for LAW=BERGSTROM-BOYCE

First line

1. Creep parameter, A.

2. Effective stress exponent, m.

3. Creep strain exponent, C.

4. Constant, E, for regularizing the creep strain rate near the undeformed state. The value of E should be non-negative. If this field is left blank, the default value of 0.01 is used.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than four)

1. Fifth field variable.

2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the dependence of the creep constants on temperature and other predefined field variables.

Data lines for LAW=HYPERB

First line

1. A. (Units of T⁻¹.)

2. B. (Units of F⁻¹L².)

3. n.

4. First field variable.

5. Second field variable.

6. Third field variable.

7. Fourth field variable.

8. Fifth field variable.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than five)

1. Sixth field variable.

2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the dependence of the creep constants on predefined field variables.

Data lines for LAW=POWER LAW

First line

1. $q_0$. (Units of FL⁻².)

2. n.

3. m.

4. a. The default is 0.0.

5. ${\dot{\epsilon }}_0$. The default is 1.0. (Units of T⁻¹.)

6. Temperature.

7. First field variable.

8. Second field variable.

9. Etc., up to four field variables.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than four)

1. Fifth field variable.

2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the dependence of the creep constants on temperature and other predefined field variables.

Data lines for LAW=STRAIN

First line

1. A. (Units of F${}^{-n}$L${}^{2n}$T${}^{-1-m}$.)

2. n.

3. m.

4. Temperature.

5. First field variable.

6. Second field variable.

7. Etc., up to four field variables.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than four)

1. Fifth field variable.

2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the dependence of the creep constants on temperature and other predefined field variables.

Data lines for LAW=USER

No data lines are needed if the PROPERTIES parameter is omitted or set to 0. Otherwise, first line

1. Give the properties, eight per line.

Repeat this data line as often as necessary to define the material properties.