applied fracture mechanics

Good Practice for Fatigue Crack Growth Curves Description 199 2 3max R, A0 A1R A2R A3R for R 0f A0 A1R for 2 R 0(3)where A0, A1, A2, A3 coefficients are equal:2S maxA0(0.825 0.34 0.05 ) cos ,2 0 maxA1(0.415 0.071 ) S ,A 1 A A A,2 0 1 3A 2 A A 1.3 0 101(4)(5)(6)(7)Smax – Newman's empirical coefficients.Determination of the above coefficients for equation that correctly approximates test data isdifficult and causes some singularities described below, when the Least Squares Method(LSM) is used.Figure 1. Fatigue crack propagation graphs: a) K=f(N); b) a=f(N) and c) da/dN=f(K)