The Measurement of Crack Initiation in Three-point Bending Fatigue Of 40Cr Steel
Wu Weiqing
(Laboratory Center Fuzhou University,Fuzhou,350002)

Abstract: A measurement of crack initiation is proposed by using system analysis method in this paper. The parameter of fatigue damage has been deduced from the model to determine the fatigue crack initiation life. Three-point-bending fatigue test have been applied to measure crack initiation of 40Cr steel and with Ni-P coatings. The results of the test reveal that the system analysis method is effective, the method can specify the initial condition of crack. The inclusions also show the initial fatigue cracks are influenced evidently when Ni-P coating is deposited.
Keywords: system analysis, fatigue damage, crack initiation life.