MATTVE

Bulk Data Entry Defines material properties for temperature-dependent nonlinear viscoelastic materials.

Format A

Williams-Landel-Ferry (Model = WLF):

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
MATTVE	`MID`	`Model`	`C1`	`C2`	`T0`

Arrhenius (Model = ARRHENIU):

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
MATTVE	`MID`	`ARRHENIU`	`E0`	`R`	`T0`	`Tz`

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
MATTVE	2	WLF	4.0	215.0	10.0

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
MATTVE	2	ARRHENIU

Field	Contents	SI Unit Example
`MID`	Material identification number that matches the identification number of the corresponding MAT1 entry. No default (Integer > 0)
`Model`	Viscoelastic material model type. WLF Williams-Landel-Ferry model Arrheniu Arrhenius model No default
`C1`	WLF constant `C1`. Default = Blank (Real > 0.0)
`C2`	WLF constant `C2`. Default = Blank (Real > 0.0)
`E0`	Activation energy for the Arrhenius model. No default (Real > 0.0)
`R`	Universal gas constant. No default (Real > 0.0)
`T0`	Reference temperature. No default (Real)
`Tz`	Absolute zero temperature. No default (Real)

Support information for MATTVE is:

Supported Analysis Types	Supported Elements
Nonlinear static and Nonlinear transient, for both small and large displacement cases	CHEXA, CTETRA, CPENTA, and CPYRA

The temperature effect on the viscoelastic material is introduced by the thermo-rheologically simple temperature effects:(1)
$σ = \int_{0}^{t} g (f (t) - f (s)) {\dot{σ}}_{0} d s$

Where,

$f (t) = \int_{0}^{t} \frac{1}{A (T (s))} d s$

The reduced time given by:

$A (T (s))$

Shift function

$T$

Temperature
For temperature-dependent material table lookup for an element with different temperatures at each node, the average temperature of all nodes of the element is considered as reference temperature for table lookup for that particular element.
Two forms of shift functions are supported:
- Williams-Landel-Ferry form(2)
  $\log_{10} (A) = - \frac{C_{1} (T - T_{0})}{C_{2} + (T - T_{0})}$
- Arrhenius form(3)
  $\ln (A) = \frac{E_{0}}{R} (\frac{1}{T - T_{z}} - \frac{1}{T_{0} - T_{z}})$