Verification of the Academician Novozhilov G.V. statement on the influence of the error in determining the stresses on the error in determining the resource on the example of the main engine parts

Abstract

The article attempts to assess the validity of the statement of Academician Novozhilov G.V. about the influence of the error in determining stresses on the magnitude of the error in determining the resource on the example of the most loaded main parts (working blades (WB) and disks) of the NK-16ST and NK-16-18ST engines. Structurally, WB (alloy ZhS6U-VI) and disks (alloy EI698-VD) are completely identical, but differ in loading parameters. The calculation of the static strength of both engines was carried out according to the theory of rods of variable cross-section and using the finite element method. The calculation of the static strength of the disks of both engines was carried out using the method of integral equations and using the finite element method. The correspondence of the results of the calculated study of the stress-strain state of the WB and the disks of both engines with their real loading was confirmed by the data of the metallurgical study of the WB and the disks after prolonged operation. During the long-term operation, the main parameters of the engines that determine the stress-strain state change. The characteristics of mechanical properties and durability of materials have a certain scattering, both in the initial state and during long-term operation of the engine, which determines the need for the use of mathematical statistics methods. For the long-term static loading characteristic of the WB and disks of both engines, the probabilistic criterion of destruction proposed by I.A. Birger was used. As a result of the conducted studies, the durability of the WB and disks of both engines were determined. As a result of calculations, it turned out that the durability estimate according to Academician Novozhilov G.V. is more accurate for the WB than for the turbine disks of both engine.