Equivalent Uniaxial Cyclic Tensile Stress as an Energy Characteristic of Metal Fatigue under Multiparameter Loading

Abstract

A concept of the equivalent stress as an energy characteristic of the material ability to resist deformation and fatigue cracking is introduced based on the principles of physical mesomechanics and synergetics. It is shown that the tensile curve of the material, the fatigue life diagram, and the kinetic curve for fatigue crack growth obtained under common experimental conditions can be considered as unified or "master" diagrams for material behavior description under multiparameter loading. Examples of determining the equivalent stress value and correction functions on the basis of the introduced concept are given for fatigue specimens subjected to biaxial cyclic loading and for in-service fatigue specimens of aircraft structures.