Abstract: A method of determining the fatigue life of a structure includes the steps of: associating a mathematical equation for total strain amplitude with the structure: ?? 2 = ? f ? E ? ( 2 ? N f ) b + ? f ? ? ( 2 ? N f ) c , where: ??/2=strain amplitude, ?f?=fatigue strength coefficient associated with a material of the structure, b=fatigue strength exponent of the material, E=cyclic modulus of elasticity of the material, 2Nf=number of cycles, ?f?=fatigue ductility coefficient of the material, and c=fatigue ductility exponent of the material; reducing the fatigue strength exponent (b) such that an elastic portion of a total strain amplitude curve associated with the equation has a reduced slope to account for variable amplitude loading for the structure; generating a total strain amplitude curve, based upon the mathematical equation: ?? 2 = ? f ? E ? ( 2 ? N f ) b reduced + ? f ? ? ( 2 ? N f ) c , where (breduced) is now