PSI - Issue 40

N.A. Makhutov et al. / Procedia Structural Integrity 40 (2022) 264–274 Nikolay A.Makhutov at al. / Structural Integrity Procedia 00 (2022) 000 – 000

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The value of the exponent m is established according to the experimental stress-strain curve of laboratory specimens under the corresponding conditions (temperatures, strain rates). ( / ) m y y e e    , (5) where е y is the yield strain of the material.

Fig. 6. Stresses in the turbine blade (x10 MPa).

4. Numerical analysis of stress states Numerical solutions of nonlinear boundary value problems in the form of expressions (1), (2), (4), (5) were developed as the methods and the computational capabilities of computer systems were improved. These methods include: - the method of successive approximations using elastic solutions with a variable secant modulus of elasticity for different strains; In the final version, the FEM turned out to be the most effective. The stress distribution patterns (Fig. 6) for the turbine blades of a turbopump unit subjected to centrifugal forces ( q ) and temperature changes ( t ) were obtained by FEM. 5. Implementation of integrated methods A fundamentally new issue in the formulation and implementation of analytical and numerical solutions according to expressions (1) – (5) for TPU rotors was the need to account for thermal effects (Makhutov, 2018; Gadenin, 2018) caused by internal heat release and an increase in material temperature t  due to cyclic plastic strains max e :   max max ; , e t t t t t F e a      , (6) - variational-difference method; - method of integral equations; - finite element method (FEM).