ERP
I/O Options and Subcase Information Entry Used to request equivalent radiated power output for all subcases or individual subcases, respectively.
Format
ERP (format_list, grid, peakoutput,MPF=mpf, MFILTER=mfilter, FREQUENCY/SOLUTION=frequency ) = option
Definitions
Argument | Options | Description |
---|---|---|
format | H3D, PUNCH, blank |
|
grid | GRID Default = blank |
|
peakoutput | PEAKOUT Default = blank |
If present, then only the filtered frequencies from the PEAKOUT card will be considered for this output. |
mpf | ALL, <N> Default = blank |
|
frequency | <SETID> Default = blank |
|
mfilter | <Real> Default = blank |
Provides a threshold under which Modal Participation Factors are not output. Output is skipped when the Modal Participation Factor divided by the maximum Modal Participation Factor (for the current mode) is below the threshold specified by MFILTER. |
option | <YES, ALL,
NO, NONE> Default = ALL |
|
Comments
- Multiple formats are allowed on the same entry; these should be comma separated. If a format is not specified, this output control applies to all formats defined by the OUTPUT command, for which the result is available.
- Multiple instances of this card are allowed. If instances are conflicting, the last instance dominates.
- For optimization, the frequency of output to a given format is controlled by the I/O option OUTPUT.
- In addition to the ERP values, the following results are output to the .pch file: total ERP over the loading frequencies, fraction of the total ERP at each loading frequency, and ERP expressed in decibels ERPdB = 10 * log10 (ERP) at each loading frequency.
- The ERP output of a panel is calculated,
as shown in Equation 2. The parameters for the speed of sound (ERPC), fluid density
(ERPRHO),
and radiation loss factor (ERPRLF) are used
in the calculation of ERP.
(1) The ERP output of a grid point ( ) is also calculated similar to that of a panel (as shown above). The parameters for the speed of sound (ERPC), fluid density (ERPRHO), and radiation loss factor (ERPRLF) are used in the calculation of ERP output for a particular grid.(2) Where,- Normal velocity
- Associate area of each grid on the panel
- The calculation of ERP in decibels (dB)
is performed using the PARAM data RHOCP and ERPREFDB in
Equation 3. ERPREFDB is the
reference value in dB and RHOCP is the scale
factor:
(3) - At least one of the Bulk Data Entries ERPPNL or PANELG (TYPE=ERP) needs to be specified, if the ERP Output Request is used.
- Modal Participation Factor output for Equivalent Radiated Power is supported in PUNCH and H3D files. Either FREQUENCY or SOLUTION can be used as the keyword to indicate the loading frequency set.
-
The direction of normals of elements selected as a panel for ERP output should be consistent. OptiStruct will automatically flip normals of elements which have inconsistent normals if such elements belong to panels selected for ERP output.