On the application of Gatts equation to the description of fatigue curve

The peculiarities of the Gatts function in the description of fatigue curve have been analyzed for the welded joint of structural low-carbon steel and structural alloyed steel 30KhGSA as an example. It has been shown that the parameter (1–C) = 0.5 in the known equation of fatigue curve has limited application. Simplified methods for the calculation of Gatts equation parameters both for known and unknown physical endurance limit are presented. A method of successive approximations on the basis of test data both at two stress levels and the minimum mean-square deviation of durability logarithm and at three stress levels and mean durabilities corresponding to them is proposed for the determination of endurance limits of materials and structural elements.