I.S. Nikitin - Dr. Sc. (Phys.-Math.), Professor, Department of physics, MATI - Russian State Technological University (Moscow); Leading Research Scientist, Institute of Computer Aided Design of the RAS (Moscow). E-mail: i_nikitin@list.ru P.A. Yushkovskiy - Post-graduate Student, Department of physics, MATI - Russian State Technological University (Moscow). E-mail: abrahas.23@gmail.com

The paper deals with the mathematical modeling of the fatigue fracture of the responsible elements of aircraft structures, such as a gas turbine compressor disks. Two alternative modes of cyclic loading are studied - flight loading cycles (low cycle fatigue) and high-frequency vibrations of the disk and the blades (very-high-cycle fatigue). A variant of the Sines - criterion of multiaxial low-cycle fatigue fracture is suggested taking into account the structural anisotropy of fatigue properties. Also a generalization of this criterion is suggested for the case of very-high-cycle fatigue taking into account the similarity of the left and right branches of the bimodal fatigue curve. On this basis estimations of the durability are obtained and the damaged areas are determined for the elastic disks of variable thickness for different regimes of fatigue fracture. It follows from the calculations that the values of durability in real-time for these regimes are sufficiently close. Therefore, alternative mechanisms of fatigue fracture should be considered simultaneously in the study of safe operation conditions.

 

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