ON THE DISTRIBUTION OF RAINFLOW RANGE FOR GAUSSIAN RANDOM-PROCESSES WITH BIMODAL PSD

The distribution of rainflow range is investigated for the Gaussian ra ndom process using bimodal PSD. The new method evaluates the distribut ion of range by taking the sum of two Rayleigh distributions which cor respond to two dominant frequencies in bimodal PSD. Representative dis tribution data have been obtained from rainflow analysis for simulated time histories. The applicability of the proposed method is examined for the range distribution generated by the simulation. It is shown th at the method estimates the distribution of range with high accuracy e ven, in the case of a random wave with a large irregularity factor. Si nce range data for unimodal PSD can be evaluated by Rayleigh approxima tion, the new method for bimodal PSD greatly extends the region of ana lytical treatment.