**PMLOPT**, * PSYS*,

`Lab`

`Xminus`

`Xplus`

`Yminus`

`Yplus`

`Zminus`

`Zplus`

`MixOpt`

Compatible Products: – | – | – | Enterprise | Ent PP | Ent Solver | –

`PSYS`

PML element coordinate system number.

may be 0 (global Cartesian) or any previously defined local Cartesian coordinate system number (>10). Defaults to 0. (Not used for IPML.)`PSYS`

`Lab`

Label defining the number of dimensions (not used for IPML):

**ONE**—

A one-dimensional PML region.

**THREE**—

A three-dimensional PML region (default).

`Xminus`

For PML, normal reflection coefficient (harmonic analysis) or attenuation factor (static structural analysis) in negative X direction of

. Defaults to 1.E−3 (equivalent to -60 dB) for a harmonic analysis and 30 for a static structural analysis.`PSYS`

For IPML, normal reflection coefficient (harmonic analysis); the default value is calculated by the program.

`Xplus`

Normal reflection coefficient (harmonic analysis) or attenuation factor (static structural analysis) in positive X direction of

. Defaults to 1.E−3 (equivalent to -60 dB) for a harmonic analysis and 30 for a static structural analysis. (Not used for IPML.)`PSYS`

`Yminus`

Normal reflection coefficient (harmonic analysis) or attenuation factor (static structural analysis) in negative Y direction of

. Defaults to 1.E−3 (equivalent to -60 dB) for a harmonic analysis and 30 for a static structural analysis. (Not used for IPML.)`PSYS`

`Yplus`

Normal reflection coefficient (harmonic analysis) or attenuation factor (static structural analysis) in positive Y direction of

. Defaults to 1.E−3 (equivalent to -60 dB) for a harmonic analysis and 30 for a static structural analysis. (Not used for IPML.)`PSYS`

`Zminus`

Normal reflection coefficient (harmonic analysis) or attenuation factor (static structural analysis) in negative Z direction of

. Defaults to 1.E−3 (equivalent to -60 dB) for a harmonic analysis and 30 for a static structural analysis. (Not used for IPML.)`PSYS`

`Zplus`

Normal reflection coefficient (harmonic analysis) or attenuation factor (static structural analysis) in positive Z direction of

. Defaults to 1.E−3 (equivalent to -60 dB) for a harmonic analysis and 30 for a static structural analysis. (Not used for IPML.)`PSYS`

`MixOpt`

Key for the evanescent wave:

**NO**—

Only the propagating wave is attenuated (default). The PML parameter is set to s = 1–jβ.

**YES**—

Both the propagating wave and the evanescent wave are attenuated. The PML parameter is set to s = α–jβ (α > 1). The program sets the coefficient α values in terms of the normal reflection coefficients.

The **PMLOPT** command can be used to define perfectly
matched layers (PML) for acoustic or structural analyses. Each PML region must have a uniquely
defined PML element coordinate system (**PSYS**). Normal reflection coefficient
values for a harmonic analysis must be less than 1.

The **PMLOPT** command can also be used to define
irregular perfectly matched layers (IPML) for acoustic analyses. Normal reflection coefficient
values for a harmonic analysis must be less than 1.

Issue **PMLOPT**,STAT to list the current normal reflection
coefficient or attenuation factor settings for a PML or
IPML region. Issue **PMLOPT**,CLEAR to clear all normal reflection
coefficient settings and restore them to the defaults.

Issue **PMLOPT**,PSYS,CLEAR to clear all normal reflection
coefficient settings for the specified PML element
coordinate system and restore them to the defaults.

See Artificially Matched Layers in the Mechanical APDL Acoustic Analysis Guide for more information about using perfectly matched layers (PML) and irregular perfectly matched layers (IPML).