Magnetic Circuit for Embedded Tendon Damage Evaluation
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Solution Overview
Problem
Existing methods cannot effectively evaluate damage to magnetic linear bodies embedded in concrete, as they require the magnetic linear body to be exposed, and they suffer from significant loss of magnetomotive force and increased weight due to the design of damage evaluation apparatuses.
Innovation Solution
A damage evaluation apparatus that includes a magnetizer with an excitation coil and yokes forming a magnetic circuit, where plate-shaped yokes with large cross-sectional areas are used to reduce magnetic resistance and weight, allowing for effective detection of magnetic flux changes or leakage flux through the embedded magnetic linear body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a probe coil is used to surround the magnetic linear body for damage detection, then the detection capability is improved, but the method becomes inapplicable to embedded magnetic linear bodies in concrete
Solution Approach 1:
The patent introduces a magnetic circuit as an intermediary system between the detector and the embedded magnetic linear body. The magnetic circuit includes a magnetizer that generates magnetic flux and a detector that measures flux changes, allowing indirect detection through the concrete structure without requiring direct contact or exposure of the magnetic linear body.
Solution Approach 2:
The patent replaces the mechanical probe coil system with a magnetic field-based detection system. Instead of physically surrounding the magnetic linear body with a coil, the system uses magnetic flux generation and detection through the concrete medium, substituting mechanical contact with electromagnetic field interaction.
2Force
If traditional yoke structures are used in the magnetizer, then the magnetic force generation is sufficient, but the apparatus weight increases significantly
Solution Approach 1:
The patent divides the traditional solid yoke structure into segmented components: a magnetizer unit and a detector unit that can be separated. The magnetizer contains the excitation coil and generates magnetic flux, while the detector measures flux changes. This segmentation allows the heavy yoke structure to be eliminated or minimized in the detector portion, reducing overall apparatus weight while maintaining magnetic force generation capability.
Solution Approach 2:
The patent extracts the heavy yoke material from the detector portion, keeping only the essential excitation coil in the magnetizer. The magnetic circuit is completed through the concrete structure itself rather than requiring heavy external yokes, thereby removing unnecessary weight from the moving apparatus while maintaining sufficient magnetic force generation.
3Strength
If the magnetic linear body is embedded in concrete, then the structural integrity is improved, but the loss of magnetomotive force increases due to magnetic resistance
Solution Approach 1:
The patent optimizes parameters of the magnetic circuit including the excitation coil winding configuration, turn density, and current characteristics to compensate for the magnetic resistance introduced by the concrete embedding. By adjusting these parameters, the system maintains sufficient magnetomotive force despite the energy loss through the concrete medium.
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 efficient evaluation of damage to magnetic linear bodies embedded in concrete by reducing magnetic resistance and loss of magnetomotive force, while minimizing the weight of the apparatus, thereby improving the assessment of abrasion, corrosion, and severance.
Implementation Method 1
forming a magnetic circuit by passing an electric current through an excitation coil by the magnetizer
Implementation Method 2
a detector for detecting an amount of change in magnetism produced from a damaged area of the magnetic linear body magnetized by the magnetic force generated by the magnetizer
Data Source
AI summary
A damage evaluation apparatus, to evaluate damage to a tendon embedded in concrete. The apparatus includes a magnetizer for generating magnetic force, and a detector for detecting change in magnetism produced from a damaged area of the tendon when magnetized. The magnetizer includes a excitation coil; an iron core passing through a center hole of the excitation coil; a pair of columnar yokes connected to respective ends of the iron core and extending toward the concrete; and a pair of plate-shaped yokes connected to the pair of columnar yokes at a distal end thereof for forming magnetic poles having spread along the surface of the concrete. By passing an electric current through the excitation coil, a magnetic circuit is formed by the yoke shaft, the pair of columnar yokes, the pair of plate-shaped yokes, and the tendon over a range thereof situated between the pair of plate-shaped yokes.