Method and system for measuring natural frequencies of pipelines

Abstract

The invention discloses a method for measuring natural frequencies of pipelines. The method includes steps of 1), respectively mounting excitation sensors and receiving sensors on the to-be-measured pipelines; 2), determining excitation frequencies according to numerical value ranges of the required natural frequencies, and setting excitation durations t<1> and measurement durations t<2>; 3), carrying out excitation by the aid of the excitation sensors on the pipelines and acquiring time-domain waveforms of detection signals by the aid of the receiving sensors; 4), computing amplitude spectra of the detection signals in time intervals [t<1>, t<2>] or [0, t<1>] or [0, t<2>] by the aid of the time-domain waveforms and acquiring amplitude spectra of the detection signals; 5), acquiring the natural frequencies of the to-be-measured pipelines according to amplitudes of the amplitude spectra. Each measurement duration t<2> is longer than or equal to 2 times the corresponding excitation duration t<1>. The method has the advantages that the high-order natural frequencies of the pipelines can be quickly acquired by the aid of the method for detecting guided waves on the basis of magnetostrictive effects, influence of the detection sensors on vibration conditions of the pipelines can be ignored, and the detection accuracy and repeatability can be improved.

Description

technical field [0001] The invention belongs to the field of non-destructive testing equipment, and more specifically relates to a method and system for measuring the natural frequency of a pipeline. Background technique [0002] Pipelines are widely used in water supply, drainage, heat supply, gas supply, long-distance transportation of oil and natural gas, agricultural irrigation, hydraulic engineering and various industrial installations. The movement of the fluid medium will cause the vibration of the pipeline and cause the wear of the connecting parts. If things go on like this, it is easy to cause leakage. And some media are explosive, toxic or destructive to the environment. Once leaked, it will cause casualties, property losses, environmental pollution and other huge economic losses. [0003] In the design of pipeline structure, the natural frequency is a very important physical quantity, especially for pipelines with finite length, such as gun tubes and heat exchan...

AI Technical Summary

Problems solved by technology

The hammering method uses a percussion hammer with a force sensor, which depends entirely on the skilled technique of the experimenter, and the frequency band range of the excitation is generally low

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