IHS ESDU Cycle counting methods for the estimation of fatigue life. 06010

ESDU 06010 is the second in a series of Items devoted to fatigue damage under random loading and is concerned with the estimation of fatigue life from stress histories in the time domain when a structure is subjected to random loading from, for example, an aerodynamic noise. Different methods of counting the number of cycles in the time history are described, including peak-valley, range and rainflow counting. The most important method is rainflow cycle counting and computer programs are available to realise the method. Program B0610 creates an input file for the main program A0610. Program A0610 makes use of the four-point method to obtain the probability density functions of the stress ranges of the rainflow cycles. In order to determine the fatigue life of the structure the S-N curve relevant for the structure has to be known from, for example, simulated random acoustic loading tests (as described in ESDU 72015 and ESDU 73010).