Vibration strength of structures based on the theory of cracking and fatigue curves

Abstract

The algorithm for calculating a fatigue crack formed in force parts of structures under the harmonic vibration load has been presented. The source data for calculating an unknown quantity are fatigue curves in the material and the assumed linearity of the first section of the kinetic diagram of the fatigue fracture. All of the necessary parameters for describing the law of crack propagation in the form proposed by Paris are determined by the characteristics of the fatigue curve. This approach shows that the fracture of the thin-walled force parts of structures with a thickness of less than 2 mm (the size of a fatigue crack for which the fracture of samples is tested to develop the fatigue curve) occurs at a smaller number of cycles than that shown in the fatigue curve for the same stress amplitude.