*ACOUSTIC CONTRIBUTION

Request the computation of the acoustic contribution factors for the linear, eigenmode-based, steady-state dynamic procedure.

This option is relevant only during linear steady-state dynamics analyses that use the natural modes of the system (STEADY STATE DYNAMICS without the DIRECT parameter). To enable computation of the acoustic contribution factors, the preceding FREQUENCY step must activate the SIM architecture, and the ACOUSTIC COUPLING parameter should be set to PROJECTION (uncoupled modes).

This page discusses:

See Also
In Other Guides
Acoustic Contribution Factors in Mode-Based and Subspace-Based Steady-State Dynamic Analyses
Natural Frequency Extraction
Mode-Based Steady-State Dynamic Analysis
Subspace-Based Steady-State Dynamic Analysis

Products Abaqus/Standard

Type History data

LevelStep

Required parameters

ACOUSTIC NODES

Set this parameter equal to the name of a node set containing the nodes in the acoustic domain. This set defines the locations of the response nodes—the nodes at which the acoustic contribution factors are determined.

NAME

Set this parameter equal to the name that will be used to refer to the acoustic contribution factor. This name will be used to define/access the SIM data set for the acoustic contribution factor.

TYPE

Set TYPE=MODAL ACOUSTIC to specify acoustic modal contribution factors.

Set TYPE=MODAL STRUCTURAL to specify acoustic structural modal contribution factors.

Set TYPE=MODAL LOAD to specify acoustic load modal contribution factors.

Set TYPE=LOAD to specify acoustic load contribution factors.

Set TYPE=PANEL to specify panel contribution factors.

Set TYPE=GRID to specify grid contribution factors.

Optional parameters

OUTPUT

Set OUTPUT=FIELD to request field output of the computed acoustic contribution factors to the output database (.odb) file. This value is relevant only for TYPE=GRID. If you specify OUTPUT=FIELD, you cannot request output of the grid acoustic contribution factors to the SIM database (.sim) file.

Set OUTPUT=HISTORY to request history output of the computed acoustic contribution factors to the output database (.odb) file.

STRUCTURAL NODES

This parameter is relevant only for TYPE=PANEL or TYPE=GRID.

Set this parameter equal to the name of the node set containing the nodes on the acoustic-structural interface. The node set specifies the source nodes for panel and grid contribution factors.

If both the SURFACE and STRUCTURAL NODES parameters are included, the resulting node set is defined as the union of the node set specified with the STRUCTURAL NODES parameter and the node set obtained from the surface specified by the SURFACE parameter.

If both the STRUCTURAL NODES and SURFACE parameters are omitted, all structural nodes on the acoustic-structural interface are used to compute the acoustic contribution factors.

SURFACE

This parameter is relevant only for TYPE=PANEL or TYPE=GRID.

Set this parameter equal to the name of the surface containing the structural nodes on the acoustic-structural interface. The surface specifies the source nodes for panel and grid contribution factors.

If both the SURFACE and STRUCTURAL NODES parameters are included, the resulting node set is defined as the union of the node set specified with the STRUCTURAL NODES parameter and the node set obtained from the surface specified by the SURFACE parameter.

If both the STRUCTURAL NODES and SURFACE parameters are omitted, all structural nodes on the acoustic-structural interface are used to compute the acoustic contribution factors.

Data line to select the natural eigenmodes for the modal contribution factors

First (and only) data line

  1. fmin, the lower bound of the frequency range. This data item is ignored if TYPE=LOAD, TYPE=PANEL, or TYPE=GRID.

  2. fmax, the upper bound of the frequency range. This data item is ignored if TYPE=LOAD, TYPE=PANEL, or TYPE=GRID.

  3. These bounds will be applied to the active eigenmodes (the eigenmodes selected with the SELECT EIGENMODES option for the current STEADY STATE DYNAMICS step).