A new multiparameter model is proposed for the characterization of fatigue crack growth. The model assesses the combined effects of identifiable multiple variables that can contribute to fatigue crack growth. Mathematical expressions are presented for the determination of fatigue crack growth rates, da/dN, as functions of multiple variables, such as: stress intensity factor range, ΔK; stress ratio, R; closure stress intensity factor, Kmax, Kcl and the maximum stress intensity factor, frequency, Ω and temperature, T. A generalized emperical methodology is proposed for the estimation of fatigue crack growth rates as functions of these variables. The validity of the new methodology is then verified by making appropriate comparisons between predicted and measured fatigue crack growth data obtained from experiments on Ti-6Al-4V, in-conel 718 and HY80 steel. The multiparameter predictions are shown to be in close agreement with experimental data.

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