HARFRQ
HARFRQ, FREQB
, FREQE
, --, LogOpt
, FREQARR
, Toler
Defines the frequency range in a harmonic analysis.
FREQB
Frequency (Hz) at the beginning of the
FREQB
toFREQE
range (ifFREQE
>FREQB
). IfFREQE
is blank, the solution is done only at frequencyFREQB
(the central frequency of octave bands, whenLogOpt
= OB1, OB2, OB3, OB6, OB12 or OB24).FREQE
Frequency at end of this range. For non-logarithm spacing (
LogOpt
is blank), solutions are done at an interval of (FREQE
-FREQB
) /NSBSTP
, ending atFREQE
, and no solution is done at the beginning of the frequency range,FREQB
.NSBSTP
is input via the NSUBST command. See the EXPSOL command documentation for expansion pass solutions.- --
Reserved.
LogOpt
Logarithm frequency span. Solutions are done at an interval of (log(
FREQE
) - log(FREQB
)) / (NSBSTP
-1), (NSBSTP
>1). The central frequency or beginning frequency is used forNSBSTP
= 1. Valid values are:OB1
—
Octave band.
OB2
—
1/2 octave band.
OB3
—
1/3 octave band.
OB6
—
1/6 octave band.
OB12
—
1/12 octave band.
OB24
—
1/24 octave band.
LOG
—
General logarithm frequency span.
FREQARR
An array containing frequency values (Hz). Combined with the tolerance argument,
Toler
, these values are merged with values calculated based on the specifications fromFREQB
,FREQE
, andLogOpt
, as wellNSBSTP
on the NSUBST command andClust
on the HROUT command. Enclose the array name in percent (%) signs (for example, HARFRQ,,,,,%arrname%). Use *DIM to define the array.Toler
Tolerance to determine if a user input frequency value in
FREQARR
is a duplicate and can be ignored. Two frequency values are considered duplicates if their difference is less than the frequency range multiplied by the tolerance. The default value is 1 x 10-5.
Notes
Defines the frequency range for loads in the harmonic analysis (ANTYPE,HARMIC).
Do not use this command for a harmonic ocean wave analysis (HROCEAN).
When frequencies are user-defined, the array FREQARR
must be
one-dimensional and contain positive values. User-defined frequency input is not supported for
the frequency-sweep Variational Technology method
(HROPT,VT ) or the harmonic balance method (HROPT,HBM).
This command is also valid in PREP7.