Equivalent Fatigue Life and Its Application in Fatigue Reliability Design
For the high cost and few specimens of the fatigue property evaluation of the key components,a very small sampling P-S-N(fatigue life reliability design curve)measurement method,which is named as the equivalent fatigue life method(EQ method)is analyzed and determined.The EQ method is applied to fitting the P-S-N of the four metals widely used in aeronautics and astronautics:18Cr2Ni4WA steel,LY12CZ aluminum alloy,Ti-6Al-4V titanium alloy and Incoloy 903 high temperature alloy,which also are compared with the standard methods suggested by GJB/Z 18A 2005,ISO 12107:2012 and ASTM.Finally,the accuracy and test time of P-S-N determined by different methods are analyzed.The results indicate that the equivalent fatigue life method can measure the P-S-N curves with low cost and high efficiency,which can be suggested to determine the fatigue life reliability design curve.
equivalent fatigue lifeP-S-Nfatigue reliabilityvery small sample size