Prediction method of creep incubation period considering restraint effect under plastic condition

Abstract

The invention discloses a method for predicting a creeping incubation period considering a constraint effect under a plastic condition. Based on Davies working, the prediction model of the creeping incubation model considering the constraint effect under the plastic condition is proposed; by utilizing a toughness degradation damage model, the creeping incubation model considering the constraint effect is calculated by introducing constraint quantity Q. By using a compact tension specimen (CT), main load is applied to carry on a creeping simulation experiment. The method disclosed by the invention has the beneficial effects that a creeping incubation period prediction model under a modified plastic condition is proposed, so that the simplified method for predicting the creeping incubation period under the plastic condition is provided; therefore, the creeping incubation period under the plastic condition can be simply and effectively predicted in the structure.

Description

technical field [0001] The invention relates to the engineering critical evaluation of creep incubation period of a high-temperature structure under plastic conditions considering restraint effects, which is to determine the creep crack initiation life of the high-temperature structure when surface cracks exist in the structure and are under plastic stress conditions. Background technique [0002] The coal-based energy structure is one of the main causes of smog in my country, and coal-fired power generation is currently the most important power generation method in my country, and this trend will exist for a long time. Therefore, in addition to changing the energy structure, developing efficient and clean ultra-supercritical (USC) units is one of the important ways to save energy and reduce emissions. However, the increase of parameters such as steam temperature and pressure has led to a very harsh service environment for the key high-temperature pipelines of the unit, espe...

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Problems solved by technology

The creep incubation period is the longest stage in the creep process, and the accurate prediction of the incubation period is of great significance for the prediction of the creep life of high-temperature structures; the incubation period prediction model proposed by Davies et al. based on the ductile dissipation model considers The integrity of the stress change in the creep process, but the influence of the restraint effect of the structure on the incubation period has not been studied; in recent years, researchers have conducted a lot of research on the influence of the restraint effect on the growth of creep cracks

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