Prediction method for high-cycle fatigue life of single crystal air film hole member

Abstract

The invention provides a prediction method for high-cycle fatigue life of a single crystal air film hole member, and relates to the technical field of porous mediums. The method comprises the steps ofdetermining a dangerous path according to a hole distribution mode of the single crystal air film hole member; building a crystal plasticity theory model, and inputting related parameters of the crystal plasticity theory model to a finite element model; outputting stress distribution of the dangerous path through the finite element model, and obtaining a maximum main stress amplitude and a maximum resolved shear stress amplitude on the dangerous path; and building a critical distance model, determining parameters of the critical distance model according to the maximum main stress amplitude and the maximum resolved shear stress amplitude, and performing calculation by an iterative program to obtain the high-cycle fatigue life of the single crystal air film hole member. According to the method, anisotropic material properties of single crystal and a deformation mechanism of crystal slip are considered; the difficult problem of high-cycle fatigue damage nonlinearity is solved; and a prediction result is small in dispersity and high in precision.

Description

technical field [0001] The present disclosure relates to the technical field of porous media, in particular to a method for predicting the multiaxial high cycle fatigue life of nickel-based single crystal gas film hole components. Background technique [0002] Nickel-based single-crystal alloys are used as turbine blade materials, which improves the comprehensive performance of the blades to a new level. Compared with other alloys, the nickel-based single crystal superalloy eliminates the grain boundary, fundamentally eliminates the damage at the grain boundary, and greatly improves the mechanical properties of the material at high temperature. With the increase in the temperature requirements of the engine inlet, the solid blades are far from meeting the temperature requirements, and the hollow cooling blades came into being. The application of air film cooling has greatly improved the temperature bearing capacity of the blades. The air film hole in the blade destroys the ...

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Problems solved by technology

[0003] The cyclic stress amplitude of high-cycle fatigue is below the yield strength of the material, and the damage and plastic deformation are seriously localized. Therefore, the linear damage accumulation criterion is not suitable for high-cycle fatigue

Single crystal alloys have anisotropic properties in structure, and microscopically, the deformation mechanism is dominated by crystal slip. The traditional elastoplastic model cannot be applied to single crystal materials.

Under the action of porous interference, the air-tight film pores are in a complex multiaxial stress state, which makes the failure mechanism area complex

[0004] Under high-cycle fatigue loads, components generally have no obvious plastic deformation, and most of the failed components are sudden brittle fractures, which are difficult to assess and prevent damage

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