Fatigue life prediction method for geometric discontinuous structure

Abstract

The invention provides a fatigue life prediction method for a geometric discontinuous structure. The method comprises the steps of building a geometric continuous first finite element model, defininga crystal plasticity constitutive equation, and obtaining a stress-strain relation of a material under a given cyclic load condition; carrying out a uniaxial tensile test and a uniaxial fatigue test to obtain a tensile curve and a hysteresis loop; fitting through a test parameter method to obtain a tensile curve and a hysteresis loop, and obtaining the material parameters and a fatigue plastic slip critical value required by a crystal plasticity constitutive equation; establishing a second finite element model of the geometric discontinuous structure, and obtaining a stress-strain relationshipand a single-cycle fatigue plastic slip value of each cycle; and calculating to obtain the crack initiation life of the notch sample. According to the fatigue life prediction method for the geometricdiscontinuous structure, the fatigue analysis of the geometric discontinuous structure at different temperatures can be better achieved, the crack initiation position can be accurately predicted, andthe fatigue life prediction method has the advantages of being visual, high in applicability and high in accuracy.

Description

technical field [0001] The invention relates to the field of life prediction of notch-containing structures, in particular to an ABAQUS-based fatigue life prediction method. Background technique [0002] In the manufacturing process of aero-engines, due to the existence of objective reasons such as processing conditions, manufacturing processes and installation conditions, some surface micro-defects inevitably exist in the installation process of important parts such as turbine discs. In addition, during the operation of the aircraft, the impact of suspended solids in the air can also cause serious damage to important components such as engine blades and turbine disks. It is precisely because of the existence of these micro-defects and small gaps that the fatigue crack initiation of important components such as aero-engine turbine disks and blades is accelerated, and the fatigue life of engine components is reduced. Therefore, in order to ensure economy and safety, it is ve...

AI Technical Summary

Problems solved by technology

This type of method focuses on describing the fatigue behavior in the crack propagation stage. Its characteristics such as complex programming, poor convergence, and high calculation cost determine that this type of method is not very universal. The stress-strain response and mechanism analysis of the layer are not accurate

Images