Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Method for electromagnetically nondestructively detecting metal surface cracks by multi-frequency exciting field array

A non-destructive testing, metal surface technology, applied in the direction of material magnetic variables, etc., can solve the problems of detection of random distribution of crack defects without mentioning sensitivity, single amplitude and frequency excitation source, etc., to achieve effective detection and identification, strong use value, The effect of improving reliability

Active Publication Date: 2018-12-11
NORTHEASTERN UNIV
View PDF6 Cites 7 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The known techniques for detecting crack defects using alternating magnetic fields mostly rely on a single amplitude and frequency excitation source, which has a good effect on detecting the length and depth of crack defects, but the change of excitation frequency is very important for the detection of randomly distributed cracks. Defect Sensitivity Not Mentioned

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for electromagnetically nondestructively detecting metal surface cracks by multi-frequency exciting field array
  • Method for electromagnetically nondestructively detecting metal surface cracks by multi-frequency exciting field array
  • Method for electromagnetically nondestructively detecting metal surface cracks by multi-frequency exciting field array

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0036] In this embodiment, the test piece is made of commonly used low-carbon steel Q235 steel, with a length of 160 mm, a width of 64 mm, and a thickness of 10 mm.

[0037] In this embodiment, the excitation device such asfigure 1 As shown, it consists of a U-shaped yoke and a square excitation coil wound in the middle. The excitation coil is made of enameled wire with a wire diameter of 0.6mm. The inner length of the coil is 20mm, and the outer length of the coil is 32mm. The effective length The U-shaped yoke is made of No. 10 steel, and its relative magnetic permeability is 10000. The outer size is 100mm*20mm*35mm, and the inner size is 80mm*20mm*15mm.

[0038] In this embodiment, the excitation signal in the excitation coil is as figure 2 As shown, it is formed by superposition of 2kHz, 5kHz and 10kHz sinusoidal currents whose amplitudes are all 0.5a, and the excitation period of the multi-frequency signal is 0.5ms.

[0039] A multi-frequency excitation field array elec...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
lengthaaaaaaaaaa
lengthaaaaaaaaaa
lengthaaaaaaaaaa
Login to View More

Abstract

The invention relates to a method for electromagnetically nondestructively detecting metal surface cracks by a multi-frequency exciting field array. The method comprises the following steps: (1) generating a standard defect on the center of a to-be-detected test piece; (2) connecting an exciting apparatus and the to-be-detected test piece, and establishing a detection model; (3) acquiring a component when a coil is excited, extracting a detection signal of each data, performing the empirical mode decomposition by using EMD to obtain an eigenmode functional signal; and (4) according to the component data characteristics, precisely identifying an angle, an axial length, a peripheral length and a radial length of a crack defect, and calculating an actual size of the defect. A U-shaped magnetic yoke wound on an electrification rectangular coil is used for magnetizing the to-be-detected component to excite a defect leakage magnetic field, the disturbance signal of a magnetic field above thedefect can be acquired, the metal surface defect is detected and identified, the reliability of a detection result can be improved, and the application value for the electromagnetic nondestructive detection of the test piece with complicated defect shape is relatively high.

Description

technical field [0001] The invention belongs to the technical field of electromagnetic nondestructive detection of metal damage, and in particular relates to a method for electromagnetic nondestructive detection of metal surface cracks by a multi-frequency excitation field array. Background technique [0002] The scope of my country's oil development has moved towards seabed resources, and the number of my country's offshore oil exploration platforms along the coast continues to increase. These platforms are subject to routine safety hazard inspections every year. Under normal circumstances, the inspections are subsea steel frames and pipelines. Ordinary detection methods can no longer meet the detection needs. With the emergence of alternating electromagnetic field detection technology, this technology has been widely used in seabed detection. However, the high cost of foreign detection is not conducive to the vigorous development of this technology. Therefore, research exc...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): G01N27/83
CPCG01N27/83
Inventor 刘金海杨金崎汪刚张化光马大中卢森骧冯健贾茹杨鑫
Owner NORTHEASTERN UNIV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com