New On-Line, Real-Time RainFlow Counting Algorithm

This paper presents a new rainflow cycle counting algorithm called the Left-Right (L-R) method which bases its theory on the pattern classification procedure as proposed by Endo, et. al (1974). The L-R method provides two unique features which are improvements over the standard one pass (1P) rainflow counting algorithm developed by Downing and Socie (1982) when used for on-line, real-time cyclecounting applications. The first feature is that the L-R method bins the data constituting half cycles instead of storing the data points in array. This feature reduces the computer memory necessary to store the half cycle data by at least an order of magnitude over the 1P method. The second feature is that the L-R method resolves full cycle counts from the previously binned half cycles by usinga very fast grouping technique. This technique is much faster than the recursive pagoda-roof procedure used in the 1P method. These two features make the L-R method an improvment over the 1P method in both computer memory necessary and in computation time.