Omni-directional Shear-horizontal Wave Magnetostrictive Patch Transducer
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Solution Overview
Problem
Existing omni-directional transducers have limitations in generating and measuring shear-horizontal waves, which are non-dispersive but have limitations compared to Lamb waves, necessitating the development of magnetostrictive patch transducers capable of efficiently producing and measuring these waves.
Innovation Solution
A transducer design featuring a permanent magnet generating a magnetostatic field, a nickel patch deforming in response to magnetic fields, an insulator, and a coil wound in a specific form to induce a magnetomotive field orthogonal to the magnetostatic field, allowing for the generation of omni-directional shear-horizontal waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If typical omni-directional transducers are used to generate Lamb waves, then wave generation is achieved, but the waves exhibit dispersion properties and surface load sensitivity that limit measurement precision
Solution Approach 1:
The patent changes the fundamental wave mode parameter from Lamb waves to shear-horizontal waves, which have non-dispersive properties. This parameter change resolves the contradiction by eliminating dispersion effects that degrade measurement precision while maintaining reliable wave generation through the magnetostrictive effect.
Solution Approach 2:
The patent replaces contact-type mechanical sensors with magnetostrictive transducers that use magnetic field interactions. This substitution eliminates the need for mechanical contact, thereby avoiding surface load sensitivity issues while maintaining reliable wave generation and improving measurement precision.
2Ease of manufacture
If a coil is wound to generate a magnetomotive field parallel to the magnetostatic field, then the winding is simple, but shear-horizontal waves cannot be generated
Solution Approach 1:
The patent introduces asymmetry in the magnetic field orientation by winding the coil at a specific angle (e.g., 45 degrees) relative to the magnetostatic field direction. This asymmetric configuration enables the generation of shear-horizontal waves by creating the necessary magnetic field components, thereby achieving wave generation capability while maintaining reasonable manufacturing simplicity.
Solution Approach 2:
The patent transitions from a single-dimensional field alignment (parallel) to a two-dimensional field configuration by introducing angular orientation. The coil is wound at a specific angle to the magnetostatic field, creating both parallel and perpendicular field components that together generate shear-horizontal waves, thus achieving wave generation capability.
3Adaptability or versatility
If contact-type sensors are used for measurement, then the measurement method is simple, but application to objects where contact is impossible is limited
Solution Approach 1:
The patent replaces contact-type mechanical sensors with magnetostrictive transducers that operate through magnetic field interactions. This substitution enables non-contact measurement, significantly expanding adaptability to objects where contact is impossible (e.g., rotating parts, high-temperature surfaces) while the transducer structure remains relatively simple and integrated.
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 shear-horizontal waves in all directions, overcoming dispersion properties and surface load sensitivity issues of Lamb waves, enabling precise and efficient non-destructive inspections.
Implementation Method 1
Magnetostriction, also referred to as the Joule effect, is a phenomenon in which a mechanical strain occurs when a ferromagnetic material is located under a magnetic field.
Implementation Method 2
a coil wound on the patch and the insulator in a certain form and inducing a magnetomotive field on the patch according to an applied current
Data Source
AI summary
Provided is a transducer. The transducer includes a permanent magnet that generates a magnetostatic field, a patch disposed below the permanent magnet and formed of a material that deforms according to a magnetic field, an insulator disposed on a top surface of the patch, and a coil wound around the patch and the insulator in a certain form and allowing a magnetomotive field to be induced on the patch according to an applied current. The wound coil has a form in which directions of the magnetostatic field generated by the permanent magnet and the magnetomotive field generated by winding the coil are orthogonal to each other.