An Imaging Method of Interlaminar Cracks in Multilayer Metal Pipelines Based on Boundary Waves

Abstract

An imaging method for interlayer cracks of multilayer metal pipelines based on interface waves is disclosed. The method comprises the following steps of uniformly arranging N excitation points along the circumferential direction on the outer surface of the innermost pipe end, making a first surface wave generated by the excitation enter a detection area and converting the first surface wave into an interface wave, uniformly arranging N receiving points on the outer surface of the inner pipe immediately adjacent to the joint surface of the innermost two pipes to respectively receive a second surface wave generated by the first surface wave acting on the interface, numbering the N receiving points, converting the received second surface wave into N groups of electrical signals for respectively recording and saving according to the numbers, filtering and enveloping the N groups of electrical signals, extracting the echo time and peak value of each group of electrical signals after filtering and envelope processing, drawing a crack image in the detection area based on probability reconstruction, and using the middle overlapped part of the other two adjacent metal layers of the multilayer metal composite pipe as an imaging detection area until the crack imaging in all detection areas are drawn.

Description

technical field [0001] The invention relates to the field of nondestructive testing of mechanical structures, in particular to an imaging method for interlayer cracks in multilayer metal pipes based on interface waves. Background technique [0002] The metal composite pipe is composed of two or more different metal pipes, and the pipes of each layer are tightly combined by deformation and connection technology. Compared with single-layer metal pipes, metal composite pipes fully combine the performance advantages of the two metal materials, overcome the performance limitations of a single metal material, and are more and more widely used in industry. [0003] However, in the actual production process of the metal composite pipe, due to defects such as gaps and inclusions in the material itself, the composite pipe is prone to damage such as interlayer cracks during production. Local uplift and buckling will also cause cracking of the metal composite pipe between layers, resul...

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Problems solved by technology

[0003] However, in the actual production process of the metal composite pipe, due to the defects such as gaps and inclusions in the material itself, the composite pipe is prone to damage such as interlayer cracks in production. In addition, during the service process, due to high temperature and high pressure conditions. Local uplift and buckling will also cause cracking of the metal composite pipe between layers, resulting in performance degradation or even failure

Because these defects exist at the interface, they are generally not directly observed, and it is difficult to effectively identify them with traditional damage detection methods.

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