Embedded Magnetic Linear Body Damage Evaluation
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Solution Overview
Problem
Existing methods cannot effectively inspect magnetic linear bodies embedded in concrete for damage such as abrasion, corrosion, and severance, as they require the magnetic linear body to be exposed, and variations in distance from the evaluation apparatus affect damage assessment accuracy.
Innovation Solution
A damage evaluation apparatus with a magnetizer and detector that forms a magnetic circuit using an excitation coil, yoke shaft, and columnar yokes to maintain constant magnetic flux density along the embedded magnetic linear body, allowing for accurate damage assessment by controlling electric current based on the embedded depth and using search coils to sense changes in magnetic flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a probe coil is used to surround the magnetic linear body for damage detection, then the detection method is simple, but the magnetic linear body must be exposed and cannot be inspected when embedded in concrete
Solution Approach 1:
The patent introduces a magnetic circuit system comprising a magnetizer with excitation coil and yoke structure as an intermediary between the detector and the embedded magnetic linear body. This magnetic circuit system transmits magnetic force through the concrete medium to magnetize the embedded body, enabling detection without direct contact or exposure of the linear body.
2Adaptability or versatility
If the distance from the damage evaluation apparatus to the magnetic linear body varies, then the apparatus can adapt to different embedded depths, but the signal waveform representing damage cannot be normalized
Solution Approach 1:
The patent employs feedback control where the detector measures the actual magnetic flux density at the embedded magnetic linear body, and this measurement is fed back to adjust the excitation current dynamically. This closed-loop control compensates for distance variations and normalizes the signal waveform, ensuring consistent damage assessment accuracy regardless of embedded depth.
Solution Approach 2:
The patent changes the excitation current parameter dynamically based on the detected magnetic flux density and embedded depth. By adjusting this electrical parameter in response to measured conditions, the system maintains optimal magnetization levels and normalizes detection signals across varying distances.
3Strength
If the magnetic linear body is embedded deeper in concrete, then the structural integrity is improved, but the magnetic flux density becomes insufficient for accurate damage detection
Solution Approach 1:
The patent transforms the static excitation current into a dynamic parameter that automatically adjusts based on embedded depth and detected magnetic flux density. This dynamic adaptation allows the system to overcome the attenuation of magnetic flux with depth while maintaining accurate damage detection capability.
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 accurate evaluation of damage to magnetic linear bodies embedded in concrete by normalizing signal waveforms, regardless of distance variations, and effectively detects changes in magnetic flux due to damage like abrasion or corrosion.
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, which is used on a concrete structure having an embedded tendon to be evaluated for damage. The damage apparatus includes a magnetizer for generating magnetic force, and a detector for detecting a change in magnetism produced from a damaged area of the tendon. The magnetizer includes an excitation coil; an iron core passed through a center hole of the excitation coil; and a pair of columnar yokes connected to respective ends of the iron core and each extending toward 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, and the tendon over a range thereof situated between a pair of plate-shaped yokes. Current that flows through the excitation coil is controlled such that the magnetic flux density of the tendon is rendered constant.