Transfer-function approximations of the rainflow filter

Abstract:
The rainflow filter is a non-linear filter which can be used to eliminate small-amplitude oscillations in a signal. In this paper, two approaches for investigation of the filter by means of an approximating transfer function are presented. The estimates are obtained from rainflow-filtered spectral simulations. One method is based on clipped Gaussian processes, the other uses a spline interpolation in the filtered time series. Examples are given for processes with different types of spectral densities. A certain reduction of small-amplitude cycles is obtained by use of the transfer function, but the threshold effect, characteristic for the rainflow filter, is missed.