Calculate Vibration Response Spectrum for a PSD.
[vrms,milesrms] = vrs(psd,freq,zeta)
vrms = vrs(psd,freq,zeta,interp_type)
VRS computes the Vibration Response Spectrum from the supplied input PSD. This is the RMS solution to the response of a SDOF oscillator as a function of frequency.
PSD is an imat_fn containing the input PSD. It must have a Functiontype of 'Power Spectral Density' or 'Auto Spectrum' with the appropriate Normalization and AmplitudeUnits.
FREQ is a numeric vector containing the frequencies at which to compute the response spectrum.
ZETA is a scalar or vector specifying the damping ratio. If it is a vector, it specifies frequency-dependent damping and must be the same length as FREQ.
INTERP_TYPE is an optional input string that controls the method of interpolation. Possible values are 'loglog' (default), 'lin', 'log', 'linlog', 'loglin', and 'loglog'. If PSD is a FCN, the default is the value of the InterpolationType property of PSD.
VRMS is an imat_fn with the oscillator RMS output. If you want 3-sigma results, multiply this function by 3.
MILESRMS is an imat_fn with the RMS output using Miles' equation (frequency by frequency).