Creep fatigue residual life evaluation method based on crystal plasticity theory

Abstract

The invention provides a creep fatigue residual life evaluation method based on a crystal plasticity theory. The creep fatigue residual life evaluation method comprises the following steps of: compiling a crystal plasticity constitutive equation based on dislocation density through ABAQUS finite element software; determining material parameters of the crystal plasticity constitutive equation; performing crystal plasticity finite element simulation on the representative volume unit of a to-be-tested material to obtain mechanical responses of the to-be-tested material under different creep fatigue working conditions; extracting accumulated energy dissipation of the representative volume unit of the to-be-tested material under each cycle, and determining a local energy dissipation volume ratio of the to-be-tested material and allowable creep damage and allowable fatigue damage of the to-be-tested material; and drawing a three-dimensional creep fatigue residual life evaluation diagram, and calculating the creep fatigue residual life of the to-be-tested material. According to the creep fatigue residual life evaluation method based on the crystal plasticity theory, creep fatigue residual life evaluation of the material can be better achieved. The method has the advantages of being visual, capable of achieving evaluation 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 remaining life evaluation method based on crystal plasticity theory. Background technique [0002] For key life-limited components such as steam turbines, heat exchangers and nuclear reactors, in addition to bearing constant loads during operation, they usually also bear alternating loads caused by device start-up and stop, temperature fluctuations, etc., so the service process may be accompanied by Severe creep-fatigue load interactions reduce the service life of these critical components. In addition, the increasing demand for low energy consumption and long life makes the operating conditions of these key components more stringent. In order to ensure the integrity and reliability of high-temperature structures under creep fatigue, it is very important to establish an accurate remaining life evaluation method . [0003] In order to ensure the sa...

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Problems solved by technology

The first type is the macroscopic parameter method, which establishes a phenomenological constitutive equation to evaluate the remaining life of the material through some experimental parameters (such as Z parameters, residual strength, etc.), and this type of method cannot describe the evolution law of the microstructure of the material; the second type It is a microstructure degradation method, that is, to characterize the process of material degradation through the damage evolution law of some representative microstructure parameters in the deformation process, but this type of method cannot quantitatively describe the damage degree of the material

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