Multimode Acoustic Signal Detection in Metallic Structures
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Solution Overview
Problem
Current methods for detecting and monitoring changes in mechanical structures, such as corrosion or material loss in pipes and vessels, are inefficient due to limited range, high cost, or inability to determine specific locations of anomalies, especially in hard-to-access environments like under insulation.
Innovation Solution
A method using joint through-transmission/pulse-echo techniques with acoustic transducers to propagate and receive signals, allowing for the determination of mechanical changes and their locations by analyzing differential signals and delay profiles, enabling effective monitoring of elongated rigid structures like pipes and vessels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual inspection by removing insulation is used to detect corrosion, then detection accuracy is improved, but time consumption and cost increase
Solution Approach 1:
The patent replaces mechanical visual inspection (requiring insulation removal) with acoustic wave-based detection. Acoustic transducers transmit and receive acoustic waves through the pipe wall to detect mechanical changes such as corrosion, cracks, or material loss without physical contact or insulation removal, thereby maintaining detection accuracy while eliminating time-consuming insulation removal.
Solution Approach 2:
The patent introduces acoustic waves as an intermediary to detect mechanical changes in the pipe. The acoustic waves propagate through the pipe wall and interact with defects, carrying information about the pipe's condition back to sensors. This intermediary approach enables indirect detection without direct visual access, solving the contradiction between detection accuracy and accessibility.
2Length of stationary object
If acoustic transducers are used for long-range acoustic interrogation, then detection range is improved, but device complexity and cost increase
Solution Approach 1:
The patent employs acoustic transducers that can function in multiple modes: generating acoustic waves, receiving acoustic waves, and operating in both through-transmission and pulse-echo configurations. This multi-functionality allows a single type of device to achieve long-range detection capabilities without requiring multiple specialized apparatus, thereby reducing overall system complexity while maintaining extended detection range.
Solution Approach 2:
The patent uses periodic acoustic wave transmission and reception to achieve long-range detection. By transmitting acoustic waves in repeated cycles and analyzing the returned signals, the system can detect defects over long distances through cumulative signal processing, reducing the need for complex high-power single-shot detection apparatus.
3Reliability
If existing acoustic methods are used, then detection capability is improved, but ability to determine specific location of anomaly deteriorates
Solution Approach 1:
The patent divides the pipe into multiple discrete zones along its length, with acoustic transducers positioned at specific locations to monitor each zone. By segmenting the detection problem into zone-specific analyses and using the relative positions of transducers and the characteristics of acoustic wave travel times, the system can determine the specific location of anomalies within particular zones, thereby improving location determination accuracy while maintaining 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
This approach allows for accurate detection and localization of mechanical changes with high sensitivity and selectivity, even in complex geometries, and can monitor large areas with minimal access points, improving detection robustness and reliability over time.
Implementation Method 1
a particular location of a mechanical change or anomalous feature within a zone identified on a rigid structure may be determined by using a joint through-transmission/pulse-echo technique... whereby the originating vibrational signals are propagated in opposing directions
Implementation Method 2
a mono-tone pulse at a specific frequency with a certain time duration is employed in a pulse-echo method, from which spatial information of the changes within either zone is deduced
Data Source
AI summary
Methods for detection, monitoring, and determination of location of changes in rigid structures with arbitrarily complex geometries are described. Implementations include locating acoustic transducers that generate and receive acoustic signals at multiple locations along a surface of the rigid structure, wherein longitudinal spacing between the transducer locations define measurement zones. Acoustic signals with chosen amplitude-time-frequency characteristics excite multiple vibration modes in the structure within each zone. Small mechanical changes in the inspection zones lead to scattering and attenuation of broadband acoustic signals, which are detectable as changes in received signal characteristics as part of a through-transmission technique. Additional use of short, narrowband pulse acoustic signals as part of a pulse-echo technique allows determination of the relative location of the mechanical change within each zone based on the differential delay profiles.