Electromagnetic ultrasonic flaw detecting method for eliminating electromagnetic ultrasonic Lamb wave multi-mode influence

An electromagnetic ultrasonic and flaw detection technology, which is applied in the direction of using ultrasonic/sonic/infrasonic waves, using sound waves/ultrasonic/infrasonic waves to analyze solids, measuring devices, etc., can solve the problems of complex echo signals and undetectable problems, so as to improve detection performance, The effect of removing multimodal effects

Inactive Publication Date: 2010-08-11
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] In order to solve the problem that the echo signal is complex and undetectable due to the multi-mode characteristics of the electromagnetic ultrasonic Lamb wave in the process of realizing non-contact ultrasonic non-destru

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  • Electromagnetic ultrasonic flaw detecting method for eliminating electromagnetic ultrasonic Lamb wave multi-mode influence
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  • Electromagnetic ultrasonic flaw detecting method for eliminating electromagnetic ultrasonic Lamb wave multi-mode influence

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specific Embodiment approach 1

[0009] Embodiment 1: The electromagnetic ultrasonic flaw detection method for eliminating the multi-mode influence of electromagnetic ultrasonic Lamb waves described in this embodiment, its specific process is: first, according to the material properties and thickness of the test piece 1 in the electromagnetic ultrasonic transducer, Determine the spacing L of the meander coil 2 of the electromagnetic ultrasonic transducer and its fluctuation range is [L-ΔL, L+ΔL] and the excitation current frequency f and its bandwidth range [f-Δf, f through the meander coil 2 +Δf], causing the probe of the electromagnetic ultrasonic transducer to excite a single-mode electromagnetic ultrasonic Lamb wave in the test piece 1 or to excite multiple modes of electromagnetic ultrasonic Lamb waves with the same propagation velocity, and then start detection , the probe of an electromagnetic ultrasonic transducer is used to send a detection signal to the test piece 1, and the detection signal is recei...

specific Embodiment approach 2

[0011] Specific embodiment 2: This embodiment is a further description of specific embodiment 1. According to the material properties and thickness of the test piece 1 in the electromagnetic ultrasonic transducer described in the specific embodiment 1, the electromagnetic ultrasonic transducer is determined. The spacing L of the zigzag coil 2 and its fluctuation range are [L-ΔL, L+ΔL] and the excitation current frequency f and its bandwidth range [f-Δf, f+Δf] passed through the zigzag coil 2, so that the The method that the probe of the electromagnetic ultrasonic transducer excites the electromagnetic ultrasonic Lamb wave of a single mode in the test piece 1 is:

[0012] Step 1: Obtain the material properties of the test piece 1 in the electromagnetic ultrasonic transducer, the material properties include thickness, shear wave velocity and longitudinal wave velocity, according to the material properties and electromagnetic ultrasonic Lamb wave excitation equation

[0013] , ...

specific Embodiment approach 3

[0031] Specific embodiment three: This embodiment is a further description of specific embodiment one. According to the material properties and thickness of the test piece 1 in the electromagnetic ultrasonic transducer described in the specific embodiment one, the electromagnetic ultrasonic transducer is determined. The fluctuation range of the spacing L of the meandering coil 2 is [L-ΔL, L+ΔL] and the bandwidth range [f-Δf, f+Δf] of the excitation current frequency f in the meandering coil 2, so that the electromagnetic The method for the probe of the ultrasonic transducer to excite multiple modes of electromagnetic ultrasonic Lamb waves with the same propagation velocity in the test piece 1 is as follows:

[0032] Step A: Obtain the material properties of the test piece 1 in the electromagnetic ultrasonic transducer, the material properties include thickness, shear wave velocity and longitudinal wave velocity, according to the material properties, electromagnetic ultrasonic L...

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Abstract

The invention discloses an electromagnetic ultrasonic flaw detecting method for eliminating an electromagnetic ultrasonic Lamb wave multi-mode influence, relates to the technical field of ultrasonic detection, and solves the problem that echo signals are complex and cannot be detected caused by the multi-mode characteristic of electromagnetic ultrasonic Lamb waves in the process of realizing non-contact ultrasonic nondestructive detection by adopting the electromagnetic ultrasonic detection method at present. The method comprises the following steps: determining the distance fluctuation range of coil windings of an electromagnetic ultrasonic transducer and a bandwidth range of excitation current frequency introduced in the coil windings according to the property and the thickness of the material of a piece to be detected, so that a probe of the electromagnetic ultrasonic transducer excites single-mode electromagnetic ultrasonic Lamb waves or excites multi-mode electromagnetic ultrasonic Lamb waves with the same propagation speed in the piece to be tested; and starting detecting, acquiring a detection result signal and processing data so as to obtain the position and the size of a flaw in the piece to be detected. The method provides a foundation for the wide application of electromagnetic ultrasonic detection.

Description

technical field [0001] The invention relates to the technical field of ultrasonic detection, in particular to an electromagnetic ultrasonic flaw detection method for eliminating the multi-mode influence of electromagnetic ultrasonic Lamb waves. Background technique [0002] Lamb wave has a long propagation distance and high detection efficiency, and is a form of guided wave widely used in ultrasonic nondestructive testing. Electromagnetic ultrasonic testing technology is a relatively popular non-contact ultrasonic nondestructive testing method. It does not require acoustic coupling agents and pretreatment of the surface of the specimen. Therefore, the electromagnetic ultrasonic Lamb wave excited by electromagnetic ultrasonic technology has special advantages and is suitable for large Area, long-distance or deep underground, the detection of clad metal plate and tubular test pieces is particularly suitable, and can be used in special occasions such as high temperature and hig...

Claims

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Application Information

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IPC IPC(8): G01N29/04G01N29/07G01B17/02
Inventor 翟国富蒋韬康磊王淑娟宫佳鹏
Owner HARBIN INST OF TECH
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