Fatigue of Metal Structures Sustaining a Very Large Number of Load Cycles. The Fatigue Threshold Concept

摘要

The fatigue threshold stress intensity factor (Delta Kth) was evaluated. The influence of crack size, loading modes, stress ratio, thickness, frequency, microstructure, amplitude, temperature, and environment on Delta K is considered. Applications of Delta Kth are quoted. Specimens and test equipment for economical testing are discussed. A crack growth rate of magnitude 10 to the minus 8th power mm per cycle is suggested as a definition of a valid threshold value.