Creep fatigue life prediction method based on crystal plasticity

Abstract

The invention provides a creep fatigue life prediction method based on a crystal plasticity theory. The method comprises the following steps: establishing a representative unit model of ABAQUS based on an electron back scattering diffraction technology; correcting the back stress model and writing the back stress model into a subprogram UMAT to obtain a creep fatigue hysteresis loop; fitting a creep fatigue hysteresis loop through a test parameter method to obtain material parameters; calculating a stress-strain value of each integral point and averaging the stress-strain values to obtain a creep fatigue hysteresis loop and a post-processing cloud atlas; extracting maximum plastic slippage and energy dissipation from the creep fatigue hysteresis loop and the post-processing cloud atlas, analyzing the change rule of the maximum plastic slippage and energy dissipation along with circulation cycles, and providing creep and fatigue indication factors; and predicting the creep fatigue crackinitiation life according to the indication factor. According to the creep fatigue life prediction method, plastic slippage and energy dissipation are used as fatigue and creep indication factors, the creep fatigue damage evolution rule can be better reflected, the crack initiation position can be accurately predicted, and the 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 creep fatigue, in particular to a creep fatigue life prediction method based on crystal plasticity theory. Background technique [0002] The working environment of modern aero-engines, industrial gas engines, supercritical generators and other devices is becoming more and more complex. In addition to the constant load of the device's steady-state operation, the key life-limiting components usually also bear the load caused by the device's start-stop and temperature fluctuations. The action of alternating loads, whose service process is accompanied by severe creep fatigue load interaction, reduces the service life of these critical life-limiting components. Therefore, in order to ensure the safety and reliability of critical life-limited components, it is very important to construct an accurate creep fatigue life prediction model. [0003] In order to accurately evaluate the durability of high-te...

AI Technical Summary

Problems solved by technology

This type of method focuses on the damage analysis of similar components or components at the macro level, and cannot describe the stress-strain response and damage mechanism evolution at the micro level.

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