Seminarium i matematisk statistik
fredagen den 10 november 13.15 i MH:227

Jesper Rydén
Matematisk statistik
Matematikcentrum
Lunds universitet

Titel:
Rainflow Filtering: Approximations in the Frequency Domain

Abstract:
The rainflow filter is a non-linear filter which can be used to
eliminate small-amplitude oscillations in a signal. Rainflow cycles
with a range less than some threshold are filtered away. An advantage
of the rainflow filter, well known in applications to fatigue, is that
a considerable reduction of data is made, while the calculated total
damage is not affected.

I will discuss how a transfer-function approximation of the rainflow
filter, that is, an approximation in the frequency domain, can be
obtained from spectral simulations. To validate the so derived filter,
the capability of filtering out small cycles is investigated, as well
as the damage intensity. Further, the transfer function is used to
obtain spectra which form the basis for numerical calculations of
exact distributions for characteristic wave parameters by means of
regression-approximation technique.