Guided Wave Defect Characterization Using Dual-Frequency Amplitude Analysis
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Solution Overview
Problem
Conventional methods cannot simultaneously estimate the cross-sectional area and width of a defect part in a subject using guided waves, despite being able to locate defect positions.
Innovation Solution
A testing method that generates guided waves at two different frequencies, detects the reflected waves, and uses pre-obtained data relationships to estimate the defect cross-sectional area and width by solving simultaneous equations based on the amplitudes of the reflected waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional single-frequency guided wave testing is used, then defect position can be located, but defect cross-sectional area and width cannot be simultaneously estimated
Solution Approach 1:
The patent introduces a frequency dimension by using multiple guided wave frequencies (first frequency and second frequency) to probe the defect. By measuring reflected wave amplitudes at different frequencies and utilizing pre-obtained data relationships from calibration specimens, the system can simultaneously estimate both defect cross-sectional area and width, transforming a single-parameter measurement into a multi-dimensional characterization.
Solution Approach 2:
The patent changes the frequency parameter of the guided wave to extract different information about the defect. By varying the frequency and measuring the corresponding reflected wave amplitudes, combined with pre-obtained calibration data, the system can determine multiple defect parameters (cross-sectional area and width) that cannot be obtained with a single frequency measurement.
2Measurement precision
If guided wave frequency is increased for better resolution, then measurement precision improves, but attenuation increases reducing testing range
Solution Approach 1:
The patent utilizes multiple frequency parameters to balance resolution and attenuation. By using both lower frequency (better penetration, less attenuation) and higher frequency (better resolution) guided waves, the system can estimate defect dimensions while maintaining adequate testing range. The pre-obtained data relationships account for the frequency-dependent behavior of wave attenuation and reflection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the simultaneous estimation of defect cross-sectional area and width by utilizing pre-obtained data for each frequency, improving the accuracy of defect characterization in subjects like pipes and rods.
Implementation Method 1
AC current flowing through a coil wound around a subject generates AC magnetic field. A magnetic force from this AC magnetic field can be used to vibrate the subject, whereby a guided wave as a kind of sound waves can be generated.
Implementation Method 2
The thus-generated oscillation wave propagates through the subject along the longitudinal direction thereof.
Implementation Method 3
A reflected wave of the guided wave is detected, whereby the soundness of the subject can be tested. A guided wave is reflected as a reflected wave at a discontinuous part of the subject or at a part of a change in cross-sectional area of the subject in the circumferential direction.
Data Source
AI summary
(A) first data for defect amount estimation for the guided wave of a first frequency is obtained, the data indicating a relationship among amplitude of the reflected wave, a defect cross-sectional area and a defect width. (B) second data for defect amount estimation for the guided wave of a second frequency is obtained, the data indicating a relationship among amplitude of the reflected wave, a defect cross-sectional area and a defect width. (C) a guided wave of the first frequency is generated, and amplitude of a reflected wave is detected as first amplitude. (D) a guided wave of the second frequency is generated, and amplitude of a reflected wave is detected as second amplitude. (E) on a basis of the first and second data and the first and second amplitude, a defect cross-sectional area and a defect width of the defect part are estimated.