METHODS FOR THE CONSTRUCTION OF THE DIAGRAMS OF FATIGUE CRACK-GROWTH RATE OF MATERIALS

摘要

We study different parameters used for the construction of the diagrams of fatigue crack-growth rate of materials in the force, deformation, and energy approaches and tested for 08kp low-strength steel and 60 high-strength steel. The applicability of the dependences known from the literature for the evaluation of the crack-tip opening displacement and local strain energy at the crack tip is analyzed. It is shown that the range of local strains triangle open epsilon* and the total range of dissi-pation of local energy in a loading cycle triangle open W_t* specify the fatigue crack-growth rate in the mate-rial and that the da/dN-triangle open epsilon* and da/dN- triangle open W_t* diagrams are more sensitive to the structural and mechanical characteristics of the materials than the ordinary da/dN- triangle open KAPPA diagrams.