Transfer-function Approximations of the Rainflow Filter
Georg Lindgren and Jesper Rydén
Centre for Mathematical Sciences
Lund Institute of Technology,
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.
waves, spectrum, rainflow cycle, filtering, fatigue