Calculation of Durability and Fatigue Life Parameters of Structural Alloys Using a Multilevel Model of Acoustic Emission Pulse Flow

The issues of durability and fatigue life of various structural materials occupy an important place in the operation of equipment and elements subjected to high stresses. To correctly predict its operation time, knowledge of the unique internal structure of a particular piece of operating equipment is required. To obtain such data, a multilevel model of acoustic emission signal flow is proposed in the article, which is based on the kinetic concept of strength and the selection of various stages of destruction in the kinetics of damage accumulation. The selected information, which accounts for the hypothesis of the linear summation of damage, is used in modern models for calculating fatigue life based on kinetic parameters, e.g., the activation energy of destruction and activation volume. The fracture activation energies, activation volume, destructive load, and fatigue life of various structural alloys and steels were calculated using the proposed acoustic emission model based on static test data from various scientific literature sources. For comparison, several methods of calculating kinetic parameters based on the thermal fluctuation concept of strength were used. In addition, numerical modeling was performed to select the structural lethargy coefficient from the elastic deformation zone. The results of the proposed model are in good agreement with the experimental data and allow—within the framework of more thorough tests and with a more accurate consideration of temperature—for the application of an engineering-based approach with which to evaluate the durability and residual service life of objects.