A Life Prediction Method for Fatigue Short Crack Growth Under Multiaxial Variable Amplitude Loading

Abstract

The invention discloses a fatigue short crack growth life prediction method under multi-axial variable amplitude loading, which relates to the field of multi-axial fatigue strength theory. Multiple half-cycles, to achieve multi-axis constant-amplitude loading on each half-cycle; (2) Aiming at the characteristic that the critical surface is not fixed, the weighted critical surface is determined by the method of weighted average maximum shear stress; (3) In the weighted The multiaxial fatigue short crack growth model on the critical surface is used to obtain the crack growth of a single variable amplitude load block; (4) the plastic zone size is corrected for the crack tip, and the short crack growth life is calculated by the fracture mechanics method. This method can well describe the effect of multiaxial variable amplitude loading on crack growth. The results show that the method can better predict the short crack growth life under multiaxial variable amplitude loading.

Description

technical field [0001] The invention relates to the field of multiaxial fatigue strength theory, in particular to a method for predicting fatigue short crack growth life under multiaxial variable amplitude loading. Background technique [0002] In many engineering fields such as nuclear power plants, automobiles, airplanes and pressure vessels, structural components are subjected to complex multi-axial variable amplitude loads, and multi-axial fatigue research has become an important research topic in various countries. Compared with uniaxial loading, damage accumulation, crack initiation and propagation, and life prediction methods under multiaxial variable amplitude loading need to be considered. Therefore, it is of great engineering significance to study the life prediction method of fatigue short crack growth under multiaxial variable amplitude loading. [0003] The study of short cracks is conducive to understanding fatigue from the microscopic and submicroscopic level...

AI Technical Summary

Problems solved by technology

For multiaxial short crack growth, due to the lack of an accurate solution of the stress intensity factor and the difficulty in obtaining test data for multiaxial fatigue short cracks, the research progress of the multiaxial fatigue short crack growth model is slow.

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