Segmented Magnetostrictive Patch Array for Pipe Defect Detection
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Solution Overview
Problem
Conventional magnetostrictive transducers for generating torsional waves in structures like rods or pipes face issues with non-uniform pre-magnetization of ferromagnetic strips, leading to inconsistent measurement repeatability and inability to determine the angular position of structural defects along the circumference.
Innovation Solution
A segmented magnetostrictive patch array transducer is developed, comprising magnetostrictive patches, insulators, meander coils, and a magnetic field forming unit, which generates a high-frequency shear wave along the rod or pipe, allowing precise measurement of defect distance and angle by controlling the propagation direction of the shear wave using a magnetic field and current flow through the meander coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ferromagnetic strip is wound around a rod member to generate torsional waves, then the transducer can produce elastic guided waves, but the pre-magnetization becomes non-uniform leading to poor measurement repeatability
Solution Approach 1:
The patent divides the continuous ferromagnetic strip into discrete magnetostrictive patches arranged in an array around the rod member. Each patch can be independently magnetized and controlled, eliminating the non-uniform pre-magnetization problem that occurs with continuous strips. The segmentation allows for precise control of magnetic field distribution and wave generation.
Solution Approach 2:
The patent employs meander coils that can dynamically control the magnetization state of each magnetostrictive patch through applied current. This dynamic control enables consistent and repeatable pre-magnetization by electrically setting the magnetic state rather than relying on mechanical winding and manual magnetization processes.
2Measurement precision
If a ferromagnetic strip is used to generate torsional waves, then elastic waves can be produced, but the angular position of structural defects cannot be determined
Solution Approach 1:
By segmenting the transducer into multiple discrete patches arranged circumferentially, the system can determine the angular position of defects. Each patch corresponds to a specific angular position, allowing the system to identify which patch detects the reflected wave first, thereby determining the defect's angular location around the rod member.
Solution Approach 2:
The patent transitions from a single continuous measurement point to a multi-dimensional array of patches distributed around the circumference. This spatial distribution in the angular dimension enables the system to capture not only the distance to defects but also their angular position, providing two-dimensional defect localization.
3Power
If conventional magnetostrictive transducers are used, then torsional waves can be generated, but the wave amplitude is limited
Solution Approach 1:
The patent combines multiple magnetostrictive patches working in unison, with each patch contributing to the overall wave amplitude. By synchronously actuating multiple patches around the rod member, the system generates larger amplitude torsional waves compared to a single conventional transducer, while sharing the complexity across modular units.
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 solution enables precise detection and measurement of structural defects in rods or pipes, including both distance and circumferential angle, with improved repeatability and accuracy by generating a larger shear wave and controlling its propagation, enhancing the diagnostic capabilities for structural health monitoring.
Implementation Method 1
Magnetostriction refers to mechanical deformation of ferromagnetic materials in a magnetic field. It is also referred as the Joule effect.
Implementation Method 2
An inverse effect thereof is referred as an inverse magnetostrictive effect or the Villari effect in which a magnetic state of a material changes when stress is applied thereto.
Data Source
AI summary
A segmented magnetostrictive patch array transducer capable of generating a high frequency shear wave in a structure such as a rod or a pipe, a structural fault diagnosing apparatus including the segmented magnetostrictive patch array transducer, and a method of operating the segmented magnetostrictive patch array transducer are shown. The segmented magnetostrictive patch array transducer includes a plurality of magnetostrictive patches attached along a circumference of a rod member; a plurality of insulators that are disposed on the magnetostrictive patches; a plurality of meander coils, each of the meander coils comprising a plurality of coil lines extending along the circumference direction of the rod member on each of the insulators, wherein a current flows through adjacent coil lines in opposite directions to one another; and a plurality of magnets that respectively form a magnetic field along the circumferential direction of the rod member on the magnetostrictive patches.