3.9. Impedance Sheet

You can specify the 2 x 2 transfer admittance matrix with continuous pressure and discontinuous normal velocity across an acoustic impedance sheet using this object. For additional details, refer to Impedance Sheet topic in the Mechanical APDL Acoustic Analysis Guide.

Analysis Types

The Impedance Sheet loading condition is available for Coupled Field Harmonic, Coupled Field Modal, Coupled Field Transient, Harmonic Acoustics, and Modal Acoustics analyses.

Common Characteristics

This section describes the characteristics of the boundary condition, including the application requirements, support limitations, and loading definitions and values.

Types Supported

  • 3D Simulation: Supported.

  • 2D Simulation: Not Supported.

Geometry Types: Geometry types supported for the Impedance Sheet boundary condition include:

  • Solid: Supported.

  • Surface/Shell: Not Supported.

  • Wire Body/Line Body/Beam: Not Supported.

Topology: The following topology selection options are supported for Impedance Sheet.

  • Body: Not Supported.

  • Face: Supported.

  • Edge: Not Supported.

  • Vertex: Not Supported.

  • Nodes: Not Supported.

  • Element: Not Supported.

  • Element Face: Not Supported.

Loading Types: This boundary condition’s loading is applied as a constant only.

Loading Data Definition: Loading data specified as a constant only.

Boundary Condition Application

To apply a Impedance Sheet:

  1. On the Environment Context tab: click Acoustic Loads>Impedance Sheet. Or, right-click the Environment tree object or in the Geometry window and select Insert>Acoustics>Impedance Sheet.

  2. Define the Scoping Method. Options include Geometry Selection (default) and Named Selection. For either scoping type, you must use the Face selection filter (on the Graphics Toolbar) for geometry selection or Named Selection definition. Only faces specified in the acoustics Physics Region can be selected or defined.

  3. Define Resistance and Reactance based on the above selections.

Details View Properties

The selections available in the Details view are described below.

CategoryFields/Options/Description
Scope

Scoping Method, options include:

  • Geometry Selection: Default setting, indicating that the boundary condition is applied to a geometry or geometries, which are chosen using a graphical selection tools.

    • Geometry (Face selection only): Visible when the Scoping Method property is set to Geometry Selection.

      You use this property to specify the face or faces of bodies specified in the acoustic Physics Region. Use the Face selection filter to pick your geometry, click in the Geometry field, and then click the Apply button that displays. After you select the geometry, this property displays the geometric entities (1 Face, 3 Faces, etc.).

  • Named Selection: Indicates that the geometry selection is defined by a Named Selection.

    • Named Selection: Visible when the Scoping Method is set to Named Selection. This field provides a drop-down list of available user–defined Named Selections (face-based only).

Definition

Type: Read-only field that describes the object - Impedance Sheet.

Resistance: Specify the resistance. This property can be designated as a parameter.

Reactance: Specify the reactance. This property can be designated as a parameter.

Suppressed: Include (No - default) or exclude (Yes) the boundary condition.

Mechanical APDL References and Notes

The application applies Impedance Sheet using the IMPD label of BF command.

API Reference

See the Impedance Sheet section of the ACT API Reference Guide for specific scripting information.