RPSD
RPSD, IR, IA, IB, ITYPE, DATUM, Name, --, SIGNIF
Calculates response power spectral density (PSD).
IRArbitrary reference number assigned to the resulting variable (2 to
NV(NUMVAR)). If this number is the same as for a previous variable, the previous variable will be overwritten with this result.IA,IBReference numbers of the two variables to be operated on. If only one, leave
IBblank.ITYPEDefines the type of response PSD to be calculated:
0,1
—
Displacement (default).
2
—
Velocity.
3
—
Acceleration.
DATUMDefines the reference with respect to which response PSD is to be calculated:
1
—
Absolute value.
2
—
Relative to base (default).
NameThirty-two character name identifying variable on listings and displays. Embedded blanks are compressed for output.
SIGNIFCombine only those modes whose significance level exceeds the
SIGNIFthreshold. The significance level is defined as the modal covariance matrix term divided by the maximum of all the modal covariance matrix terms. Any term whose significance level is less thanSIGNIFis considered insignificant and does not contribute to the response. All modes are taken into account by default (SIGNIF= 0.0).The significance level definition is identical to the one used for the combination (
SIGNIFon the PSDCOM command); however, the default value is different.The significance does not apply to spatial correlation (PSDSPL) and wave propagation (PSDWAV) response power spectral density.
Notes
This command calculates response power spectral density (PSD) for the variables referenced by
the reference numbers IA and IB. The
variable referred by IR will contain the response PSD. You must issue
the STORE,PSD command first; File.psd must be available
for the calculations to occur.
See POST26 - Response Power Spectral Density in the Mechanical APDL Theory Reference for more information on these equations.