Aerospace Technic and Technology

The design and manufacture of modern, competitive, and durable aircraft necessitate increased strength and reliability of their structural components. Cracks and microcracks are among the most dangerous defects in aircraft engines, as they affect safe operation and require detailed analysis and monitoring. Changes in their dimensions during rotation can lead to failure and accidents. A computational assessment of crack kinetics in aircraft engine components under multi-mode cyclic loading within an elastic-plastic framework, using the concept of accumulated scattered damage in the material, enables the determination of the residual life of aircraft equipment. The aim of the study is to conduct a numerical analysis of the influence of crack parameters in aircraft engine fan discs on the residual life of aircraft equipment, accounting for low-cycle fatigue under multi-mode cyclic loading, using a refined computational methodology for assessing crack kinetics. An assessment of the crack resistance of a D-18T gas turbine engine fan disc in the presence of an axial scratch between two adjacent teeth of the rim, 0.15 cm deep and 9.5 cm long, under a zero-cycle loading condition corresponding to the period from aircraft takeoff to landing was performed. The analysis of the growth of a radial-axial crack in the disk rim is based on low-cycle fatigue curves for standard specimens and Peris-type fatigue failure kinetic diagrams. Computational studies of crack kinetics were conducted for cases where the inertial force from the blade tips is 10% less and 10% greater than the assumed value. The results showed that the number of cycles to failure varies by approximately 15% (increasing in the first case and decreasing in the second). An analysis of the crack resistance of gas turbine engine fan discs showed that the presence of a crack significantly affects the number of cycles to failure. Therefore, it is necessary to conduct interim inspections of the rim at least every 1,000 flight cycles to ensure reliable, stable operation and durability, and to detect potentially dangerous cracks in a timely manner. The application of the suggested methodology for assessing crack propagation and the use of the research results obtained will make it possible to reduce the costs of designing new equipment, determine the survivability of structures, establish inspection intervals to ensure operational reliability and timely cessation of operation, reduce the number of experimental studies, and contribute to enhancing the competitiveness of domestic aviation equipment.

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