Device and method for detecting pipeline closed cracks based on vibro-acoustic modulation technology

Abstract

The invention relates to a device and a method for detecting pipeline closed cracks based on the vibro-acoustic modulation technology and belongs to the pipeline nondestructive testing field. The device provided by the invention comprises a computer, a first function generator, a second function generator, a first power amplifier, a second power amplifier, a vibration exciter, an accelerometer, acharge amplifier, a first thickness concertina-type piezoelectric ceramic sheet array and a second thickness concertina-type piezoelectric ceramic sheet array, an anti-aliasing filter and a data collection card. The method provided by the invention comprises the following steps of: acquiring a pipeline first-order bending vibration inherent frequency by swept frequency excitation; taking the frequency as the one of low-frequency vibration in the vibro-acoustic modulation detection; simultaneously exciting low-frequency bending vibration and high-frequency supersonic waves into the pipeline, determining whether there exists closed cracks inside the pipeline by the existence of frequency components which equal high frequency supersonic wave frequency subtracts or adds low frequency bending vibration frequency in a received signal frequency spectrogram. The device provided by the invention is utilized to solve the problem that it is hard to detect closed cracks by traditional methods, and can be applied to detect closed cracks in industrial pipelines.

Description

technical field [0001] The invention relates to a pipeline closed crack detection device and method based on vibration and sound modulation technology, which belongs to the field of pipeline non-destructive detection. Background technique [0002] As an important part of production systems, transportation and manufacturing equipment, pipelines play an irreplaceable role in industries such as machinery, petroleum, chemical, food and urban water supply. However, the pipeline has been in service for a long time, and damages appear in the pipeline due to reasons such as the harsh environment. If these damages are not discovered in time, production accidents will easily occur, causing heavy losses to the country and the people. [0003] Cracks are one of the main defect forms of pipelines, and they often appear near the welded parts of pipelines and at bends. For the detection of cracks, the current traditional ultrasonic nondestructive testing method is based on the reflection...

AI Technical Summary

Problems solved by technology

[0006] Scholar Dmitri Donskoy’s research shows that it is not very appropriate to use the ratio MI of the side lobe to the main lobe in the signal amplitude spectrum to characterize cracks. In actual detection, it is difficult to accurately characterize the crack size due to the existence of errors [Dmitri, Alexander Ekimov , Emile Luzzato, Jean-Louis Lottiaux, Stanislav Stoupin and Andrei Zagrai. N-SCAN: New Vibro-Modulation System for Detection and Monitoring of Cracks and Other Contact-Type Defects. Smart Structures and Meterials. 2003, 5057: 400-409]

Images