Rainflow Counting is the most popular counting method in fatigue life estimation because it follows the stress-strain hysteresis loop. This counting method was named rainflow by its inventors, M. Matsuishi and T. Endo, because it graphically looks similar to rain flowing down a pagoda roof Stress time history with respect to the face reference frame. After the Rainflow counting, the several results such as Mean of stress/strain cycle, Range of stress/strain cycle and the number of stress/strain cycle from the stress/strain time history.
Figure 1 Rainflow Counting
Figure 2 The results of Rainflow counting in a 3D chart