On-site indication of fatigue damage under complex loading

Abstract A fatigue damage indicator using a microcomputer is reported. The evaluation of damage was based on the rainflow algorithm, the S/N relation and the linear damage rule. Real-time, on-site fatigue damage evaluation was achieved by the investigation of a digital system-oriented rainflow algorithm, by the adoption of an input buffer and by the use of a table where the result of calculating fatigue damage per reversal of strain is stored. A hard-wired logic for the rainflow algorithm was established and was simulated by the microcomputer. Multi-channel monitoring and its applications to cross-analysis are briefly discussed.