Axisymmetric Body Defect Detection and Reconstruction Method Based on Sound Field Wavenumber Spatial Spectrum

Abstract

The invention relates to a method for detecting and reconstructing defect of axially symmetrical bodies on the basis of wave number spatial spectra of sound fields. The method includes comprehensively detecting the axially symmetrical bodies by the aid of an ultrasonic detection system for the axially symmetrical bodies; acquiring inversion sound fields and a two-dimensional reconstruction result of each detection section by means of computing by the aid of propagation laws of ultrasonic stress waves, the wave number spatial spectra of the sound fields and finite-difference iteration processes; reconstructing three-dimensional shapes of the defect by the aid of volume rendering processes. The method has the advantages that elements of the detection sections are partitioned by the aid of finite element processes, inverted signals of ultrasonic echo signals are loaded in ultrasonic array elements, two-dimensional Fourier transformation relations between variables of plane coordinates x and y and wave numbers k<x> and k<y> of the sound fields are established, sound pressures in propagation procedures are computed according to transmission principles of the stress waves, the sound fields for transmitting sound waves of all the array elements are ultimately superposed with one another, and accordingly the shapes of the defect of the detection sections can be reconstructed; mutual effects of the signals of the multiple array elements are taken into consideration, accordingly, the reconstruction precision can be greatly improved, and the computing speeds can be increased by the aid of the wave number spatial spectra of the sound fields and fast Fourier transformation.

Description

Technical field [0001] The invention belongs to the technical field of axisymmetric body defect detection method, and specifically relates to an axisymmetric body defect detection and reconstruction method based on the acoustic field wavenumber space spectrum. Background technique [0002] Axisymmetric structure is the main structure for material processing and product production. Axisymmetric body is widely used in defense industry, aerospace, transportation and other fields. It is generally produced by metal or alloy material through warm extrusion or casting process. Due to the instantaneous temperature change, the friction between the medium and the mold, and the alternating load, the internal and surface defects of the workpiece will be caused to varying degrees. These defects will affect the normal and safe use of the product. Therefore, it is necessary to conduct non-destructive testing and evaluation during the production process and before the product is used. [0003] Th...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the technical problem of large errors in defect reconstruction results in existing axisymmetric body defect detection and reconstruction methods, and to provide an axisymmetric body defect detection and reconstruction method based on the sound field wavenumber space spectrum

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