# MAT1PT

Bulk Data Entry Defines isotropic permittivity and damping for dielectric materials.

Note: This can be used along with the MATPZO Bulk Data Entry for defining piezoelectric coupling.

## Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
MAT1PT MID PMTV         DAMP
FLAG1 FLAG2

## Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
MAT1PT 17 0.1         1.2
STRNCHG RELATIVE

## Definitions

Field Contents SI Unit Example
MID Unique material identification number.

No default (Integer > 0)

PMTV Defines the permittivity.

No default (Real > 0.0)

DAMP Damping term corresponding to the dielectric term.

No default (Real > 0.0)

FLAG1 Flag to indicate the form of definition.
STRNCHG (Default)
Indicates STRAIN-CHARGE form
STRSCHG
Indicates STRESS-CHARGE form

FLAG2 Flag to indicate type of permittivity.
ABSOLUTE (Default)
Absolute permittivity
RELATIVE
Relative permittivity
In this case, vacuum permittivity also needs to be provided by PARAM, VAPMTV.

1. The material identification number/string may be the shared with structural material property definitions (MAT1, MAT2, MAT8, MAT9 or MGASK), thermal material property definitions (MAT4, MAT5), or electrical material property definitions (MAT1EC or MAT2EC) but must be unique with respect to other dielectric materials (MAT2PT).
2. MAT1PT is supported only for solid elements.
3. The material permittivity is obtained as:(1)
$\epsilon ={\epsilon }_{0}{\epsilon }_{r}$
Where,
${\epsilon }_{0}$
Vacuum permittivity
${\epsilon }_{r}$
Coefficient defined by PMTV
The permittivity matrix, in Stress-Charge form, is expressed as:(2)
$\left[{\epsilon }_{S}\right]=\left[\begin{array}{ccc}{\epsilon }_{0}{\epsilon }_{r}& 0& 0\\ 0& {\epsilon }_{0}{\epsilon }_{r}& 0\\ 0& 0& {\epsilon }_{0}{\epsilon }_{r}\end{array}\right]$
When FLAG=STRNCHG, Strain-Charge form is defined in the card, and the permittivity matrix is expressed as:(3)
$\left[{\epsilon }_{T}\right]=\left[\begin{array}{ccc}{\epsilon }_{0}{\epsilon }_{r}& 0& 0\\ 0& {\epsilon }_{0}{\epsilon }_{r}& 0\\ 0& 0& {\epsilon }_{0}{\epsilon }_{r}\end{array}\right]$
The $\left[{\epsilon }_{T}\right]$ matrix is converted to $\left[{\epsilon }_{S}\right]$ matrix by:(4)
${\epsilon }_{S}={\epsilon }_{T}-d{c}_{E}{d}^{T}$
Where,
${c}_{E}$
Elastic matrix
$d$
Piezoelectric coupling matrix defined in MATPZO
4. For more information, refer to Piezoelectric Analysis in the User Guide.