Acoustic Thermography NDE System for In-Situ Flaw Detection
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Solution Overview
Problem
Existing nondestructive evaluation systems face challenges in inspecting large or integrated structural objects in situ, as they often require removal and cannot accurately detect subsurface flaws without altering the object's integrity or precision.
Innovation Solution
A non-contact system utilizing an electromagnetic acoustic transducer (EMAT) to generate acoustic vibrations and an infrared detector to record thermal images, synchronized by a control system and velocity interferometer, allowing for continuous imaging of a test object's surface as it or the platform moves relative to the object, enabling detection of flaws without precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional contact-based NDE methods are used, then measurement precision can be improved, but the object must be removed from its operational location and the testing process becomes complex and time-consuming
Solution Approach 1:
The patent replaces contact-based mechanical ultrasonic testing with a non-contact system using electromagnetic acoustic transducers (EMATs) to generate acoustic waves and infrared sensors to detect thermal responses. This substitution eliminates the need for physical contact and removal of the test object, enabling in-situ inspection while maintaining flaw detection precision through the coupling of acoustic excitation with thermal imaging detection
Solution Approach 2:
The patent introduces thermal energy as an intermediary to translate acoustic wave interactions with subsurface flaws into detectable thermal signals. The acoustic waves generate localized heating at flaw locations, which is then detected by infrared sensors, creating a bridge between acoustic excitation and visual detection without requiring direct contact with the test object
2Reliability
If the test object is removed for laboratory testing, then comprehensive inspection can be performed, but productivity is reduced and the object cannot be tested in its operational environment
Solution Approach 1:
The patent creates a dynamic, mobile testing system where the EMAT and infrared sensor assembly can be moved along the test object to perform comprehensive inspections. This dynamic capability allows the system to achieve complete coverage similar to laboratory testing while maintaining the object in its operational location, thereby improving productivity by eliminating removal and reinstallation time
Solution Approach 2:
The patent develops a universal testing system that can inspect various types of objects (metal plates, pipes, structures) in their operational environments without requiring specialized laboratory equipment. The system combines acoustic excitation and thermal detection in a single integrated platform that adapts to different inspection scenarios, providing both comprehensive inspection capability and operational flexibility
3Loss of information
If acoustic vibrations are applied to detect subsurface flaws, then measurement capability is enhanced, but the testing process becomes complex requiring precise synchronization and alignment
Solution Approach 1:
The patent implements feedback control by using the infrared sensor to detect thermal responses in real-time and adjusting the acoustic excitation parameters accordingly. The system monitors the thermal signal strength and timing to optimize the detection of subsurface flaws, automatically compensating for variations in material properties and flaw characteristics without requiring manual recalibration
Solution Approach 2:
The patent employs periodic acoustic excitation at specific frequencies to stimulate resonant responses from subsurface flaws. By using pulsed or continuous wave acoustic excitation at predetermined frequencies, the system enhances the thermal signal from flaws while simplifying the synchronization requirements, as the periodic nature of the excitation provides natural timing references for the detection system
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 robust, accurate detection of surface flaws on large or integrated objects in their operational environment, allowing for rapid identification of defects like cracks and disbonds without altering the object's integrity or requiring precise alignment of sensors.
Implementation Method 1
an electromagnetic acoustic transducer (EMAT) to generate acoustic vibrations
Implementation Method 2
an infrared detector to record thermal images
Implementation Method 3
acoustic thermography... acoustic vibrations... thermal images
Data Source
Figure 1~2
Figure 3~4
AI summary
A system (10) for nondestructive evaluation of a test object (12) includes a platform (14), an electromagnetic acoustic transducer (EMAT) (16) to create acoustic vibrations (18) that travel along the test object (12); an infrared detector (20) positioned to record thermal images (200) of a plurality of test areas (24, 26, 28) on the test object (12) to detect flaws (30) in the test object (12) as the platform (14) and the test object (12) move relative to each other; and a control (22) connected to actuate the EMAT (16) and the infrared detector (20), synchronize the creation of vibrations (18) with the recording of thermal images (200), receive a signal from the infrared detector (20) indicative of the thermal image (200) of the surface (23) of the test object (12), and record locations of the flaws (30) appearing on the thermal images (200) of the test areas (24, 26, 28), all as the platform (14) and the test object (12) move relative to each other.