Ultrasonic Wire Defect Detection in Civil Anchorage Zones
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Solution Overview
Problem
Existing methods for detecting defects in metal wires within cables, particularly in anchoring zones of civil engineering structures, face challenges due to the cables' embedded and protected nature, making visual inspection impossible and existing non-destructive techniques like magnetic leakage flux methods ineffective due to shielding effects and high stress concentrations.
Innovation Solution
A method utilizing high-frequency ultrasonic signals centered around a specific frequency, optimized for propagation in metal wires, allowing for non-destructive and in-situ detection of defects by emitting, reflecting, and receiving ultrasonic waves, with a frequency-radius product between 10 and 20 MHz.mm, enabling long-distance evaluation and localization of defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic leakage flux method is used for defect detection, then defect detection capability is improved, but the method becomes ineffective due to shielding effects from metallic sheath and reinforcement steels
Solution Approach 1:
The patent replaces the magnetic field-based detection method with an acoustic wave-based method. Ultrasonic waves propagate through the metal wires without being significantly affected by the metallic sheath or surrounding reinforcement steels, thereby avoiding the shielding effects that plague magnetic methods. The acoustic waves interact directly with the wire material properties and defect characteristics, enabling reliable defect detection in the anchoring zone environment.
Solution Approach 2:
The patent changes the physical parameter used for detection from magnetic properties to acoustic properties. By using ultrasonic waves with specific frequency ranges and analyzing their propagation characteristics, reflection patterns, and velocity changes, the method overcomes the limitations of magnetic field penetration through metallic structures. This parameter change allows detection to proceed despite the presence of shielding materials.
2Loss of information
If visual inspection is performed by making openings in embedded materials, then defect visibility is improved, but the method becomes destructive and localized
Solution Approach 1:
The patent replaces the mechanical approach of creating physical openings for visual inspection with a non-contact acoustic wave method. Ultrasonic transducers transmit and receive acoustic signals through the cable structure without requiring any physical access openings, thereby eliminating the destructive nature of traditional inspection methods while maintaining comprehensive defect detection capability.
Solution Approach 2:
The acoustic wave-based method provides universal applicability for defect detection throughout the entire cable length, including regions previously inaccessible to visual inspection. The method can detect defects anywhere along the wire trajectory without requiring localized openings, making the inspection process non-destructive and broadly applicable to all anchoring zone configurations.
3Length of stationary object
If low-frequency acoustic waves are used for cable evaluation, then penetration depth is improved, but defect detection precision deteriorates
Solution Approach 1:
The patent employs a dynamic frequency selection strategy where the operating frequency is adaptively chosen based on the specific inspection requirements, wire diameter, and defect type. By optimizing the frequency-radius product for each inspection scenario, the method achieves both adequate propagation distance and sufficient defect detection precision, resolving the trade-off between penetration depth and measurement accuracy.
Solution Approach 2:
The patent changes the frequency parameter to operate in the high-frequency ultrasonic range rather than low-frequency acoustic range. This parameter change enables shorter wavelengths that provide better defect resolution while still achieving adequate propagation distances through the cable structure. The high-frequency ultrasonic waves are particularly effective for detecting small defects and providing precise localization.
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 non-destructive and in-situ detection of defects in metal wires within cables, particularly in anchoring zones, by concentrating ultrasonic energy in the wire, allowing for effective evaluation of wire conditions even far from accessible ends, improving defect detection accuracy and accessibility.
Implementation Method 1
emitting a high-frequency ultrasonic signal centered around a so-called specific frequency in the metal wire; step of reflection of said ultrasonic signal in the metal wire; and step of receiving the reflected ultrasonic signal
Implementation Method 2
step of reflection of said ultrasonic signal in the metal wire
Implementation Method 3
The ultrasonic signal emitted allowing excitation of at least one high-frequency wave capable of propagating in a longitudinal direction of the metal wire... The ultrasonic signal emitted is optimized so that the wave is concentrated in the wire to be analyzed
Data Source
Figure 1a~1b
Figure 1c
Figure 2
AI summary
The invention relates to a method for detecting defects of at least one metal wire of a set of metal wires, in particular in a cable, the method including: a step of emitting a high-frequency ultrasound signal around a so-called specific frequency in the metal wire; a step of reflecting said ultrasound signal in the metal wire; and a step of receiving the reflected ultrasound signal. The emitted ultrasound signal enables the energisation of at least one high-frequency wave capable of propagating in a longitudinal direction of the metal wire and having a phase velocity that is slightly higher than a compression volume wave velocity in the metal from which the metal wire is made.