Method for predicting service life of high-temperature structural member based on nonlinear creep-fatigue interaction

Abstract

The invention discloses a high-temperature structural member service life prediction method based on nonlinear creep-fatigue interaction, and the method comprises the following steps: constructing a service life prediction model which is used for carrying out the service life prediction of a high-temperature structural member through obtaining first creep damage based on threshold stress and second fatigue damage based on average stress; the method comprises the following steps: acquiring first creep damage by acquiring creep fracture strain energy, elastic modulus, stress level and peak strain retention time of a high-temperature structural member; second fatigue damage is obtained by obtaining the plastic strain range and average stress of the high-temperature structural part under the creep-fatigue condition, the plastic hardening index of the high-temperature structural part under the pure fatigue condition and the material constant of the high-temperature structural part; based on a life prediction model, according to the first creep damage and the second fatigue damage, life prediction is conducted on the high-temperature structural part; according to the method, the limitation of a bilinear creep-fatigue life prediction method is solved, and the prediction precision of the creep-fatigue life of the material is relatively high.

Description

technical field [0001] This application relates to the technical field of material creep-fatigue life prediction, in particular, to a method for life prediction of high-temperature structural parts based on nonlinear creep-fatigue interaction. Background technique [0002] High-temperature structural parts are often served under complex and severe working conditions, such as superheaters (re)heaters in nuclear power, petrochemical and other fields, aeroengine turbine rotors, etc. These components not only bear the periodic thermomechanical cycle load (fatigue damage) that occurs during start-up and shutdown maintenance, but also bear the stable load (creep damage) caused by long-term high-temperature operation. These conditions will lead to material degradation and damage with the increase of service time, and gradually reduce the stability and safety of equipment operation. Therefore, how to accurately evaluate the damage interaction behavior of high-temperature structural...

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Problems solved by technology

[0004] In order to solve the above problems, the object of the present invention is to propose a nonlinear creep-fatigue life prediction method for the development needs of life prediction under creep-fatigue interaction conditions, which can effectively solve the existing creep-fatigue problems. The problem of large errors in life prediction methods provides a new method for evaluating the creep-fatigue performance of important components under high temperature and high pressure conditions

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