Fatigue Crack Growth Tests of Typical Components

It is difficult for high strength steel to produce fatigue striations in the fracture process of fatigue,which brings difficulty for the analysis of the appearance of the crack growth and fracture mouth analysis.A marking technique,in which the slightly smaller load was exerted on the specimens to produce the beachmark,was adopted in the process of fatigue test.The mark was used to define the appearance and the velocity of crack growth.The result of measurement was compared with the calculating result using Newman-Raju equation.