A new function for fatigue curves characterization and its multiple merits

A new function is proposed for the description of fatigue curves in both low- and high-cycle fatigue regions, i.e. for the whole region of cycles from tensile strength to permanent fatigue limit (usually described by the Palmgren function). In each cycle region it can be simplified; in fact it changes into the Basquin function in the region of finite life and an analogy of the Stromeyer function for the high-cycle fatigue region can also be obtained. In comparison with the functions mentioned above, the new function has many advantages: it allows a better fit of experimental results, its parameters have unambiguous technical and geometrical meaning and they can be determined with higher accuracy. The function and its simplifications are also more suitable for extrapolation and interpolation of fatigue curves in low-cycle and very-high-cycle regions.