Omni-Directional Shear-Horizontal Wave EMAT Design
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Solution Overview
Problem
Existing omni-directional transducers are limited in generating and measuring shear-horizontal waves, which have non-dispersive properties and are not as efficient as Lamb waves, necessitating the development of transducers capable of efficiently producing and measuring shear-horizontal waves for phased array systems.
Innovation Solution
A transducer design featuring a circular ring permanent magnet unit with opposite magnetic poles and a coil wound in a diametrical and circumferential direction, where the current direction is orthogonal to the magnetic field, generating a vertical magnetic flux to produce shear-horizontal waves efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If typical omni-directional transducers are used to generate Lamb waves, then wave generation capability is achieved, but the waves exhibit dispersive properties and sensitivity to surface loads which limit inspection precision
Solution Approach 1:
The patent changes the wave mode parameter from Lamb waves to shear-horizontal waves, which fundamentally alters the wave properties to achieve non-dispersive characteristics and reduced sensitivity to surface loads. This parameter change in wave type resolves the contradiction by providing both inspection precision and wave stability.
2Productivity
If conventional transducer designs are used, then manufacturing simplicity is maintained, but the ability to generate shear-horizontal waves efficiently is insufficient
Solution Approach 1:
The patent employs a circular ring permanent magnet arrangement with specific diametrical width configuration to generate shear-horizontal waves. The curved/circular geometry of the magnet arrangement enables efficient shear-horizontal wave generation while maintaining manufacturing feasibility through standardized circular component fabrication.
3Productivity
If the permanent magnet diametrical width is increased to improve shear-horizontal wave generation, then wave generation efficiency improves, but the transducer size increases
Solution Approach 1:
The patent optimizes the permanent magnet diametrical width to be substantially equal to half the wavelength of the target shear-horizontal wave. This parameter optimization achieves efficient wave generation at a controlled size by establishing a direct relationship between magnet dimension and wave characteristics, resolving the contradiction between generation efficiency and transducer compactness.
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
The transducer effectively generates and measures omni-directional shear-horizontal waves, overcoming dispersion properties and sensitivity to surface loads, enabling precise and efficient inspections with improved non-destructive examination capabilities.
Implementation Method 1
a permanent magnet unit formed in a form of a circular ring having upper and lower surfaces each having a predetermined diametrical direction width while having a circular through-portion in a central portion of the permanent magnet unit, the permanent magnet unit generating a vertical magnetic flux due to opposite magnetic poles that are formed in the upper and lower surfaces
Implementation Method 2
a coil wound in a diametrical direction across an area between an inner surface formed by the circular through-portion of the permanent magnet and an outer surface formed by an outer circumference of the permanent magnet and also wound in a circumferential direction of the permanent magnet, wherein the coil includes a conductive material so that a current is applied to the coil, and when an alternating current is applied to the coil, a direction of the alternating current flowing along the coil and a direction of a magnetic field passing through the coil are orthogonal to each other
Data Source
AI summary
A transducer is provided. The transducer includes: a permanent magnet unit formed in a form of a circular ring having upper and lower surfaces each having a predetermined diametrical direction width while having a circular through-portion in a central portion of the permanent magnet unit, the permanent magnet unit generating a vertical magnetic flux due to opposite magnetic poles that are formed in the upper and lower surfaces; and a coil wound in a diametrical direction across an area between an inner surface formed by the circular through-portion of the permanent magnet and an outer surface formed by an outer circumference of the permanent magnet and also wound in a circumferential direction of the permanent magnet, wherein the coil comprises a conductive material so that a current is applied to the coil, and when an alternating current is applied to the coil, a direction of the alternating current flowing along the coil and a direction of a magnetic field passing through the coil are orthogonal to each other.