Small pipe vibration stress measurement and fatigue life evaluation method for nuclear power plant

Abstract

The invention provides a small pipe vibration stress measurement and fatigue life evaluation method for a nuclear power plant. The method comprises the steps that S1) displacement sensors arranged along the axial direction of a pipe at interval are mounted on the pipe, and each displacement sensor serves as a measurement point; S2) the displacement sensors obtain vibration displacement values of the corresponding measurement points, the vibration deformation radius of curvature of the pipe at present time is calculated according to horizontal position information of the measurement points by means of the Pythagoras theorem; S3) structure parameters of the pipe to be measured are obtained; and the vibration bending stress of the pipe at the present time is calculated according to the structural parameters and the radius of curvature; and S4) the displacement sensor obtains real-time vibration displacement value and frequency information of any measurement point, a Miner linear accumulation theory is used to calculated linear accumulated damage of pipe vibration, and residual life of the pipe is calculated. A non-contact measurement manner is used to calculate the vibration bending stress and fatigue life of the pipe rapidly, and the technical effect is good.

Description

technical field [0001] The invention relates to the technical field of nuclear power plant pipeline stress analysis, in particular to a method for measuring vibration stress and fatigue life assessment of small nuclear power plant pipelines. Background technique [0002] Due to the long-term high-temperature and high-pressure working conditions of nuclear power plant pipelines, fatigue damage is prone to occur under the action of internal and external loads, which may lead to pipeline cracking, fluid leakage in the pipeline, and even pipeline fracture. Small pipes (less than 3 inches in outer diameter) are high-incidence areas for fatigue failure events due to their large number, complex structure, and wide distribution. In order to ensure the safe operation of the pipeline, it is necessary to reasonably predict its service life and even optimize and improve the design scheme. One of the key measures is to obtain the vibration stress of the pipeline. Therefore, a reasonable ...

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Problems solved by technology

[0006] Aiming at the problems of high radiation and high temperature in the vibration stress measurement of pipelines in the prior art, the present invention provides a method for vibration stress measurement and fatigue life evaluation of small nuclear power plant pipelines, which can measure the vibration displacement value and frequency information of the pipeline, thereby Realize the rapid calculation of pipeline vibration stress and mechanical fatigue life

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