Ultrasonic Surface Wave Velocity Determination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current ultrasonic non-destructive testing methods, particularly those using full-matrix capture (FMC) and total focusing method (TFM), face challenges in accurately determining acoustic velocities in test objects, which affects the reliability of TFM images due to unknown material composition and imprecise velocity measurements, especially in steel and weld inspections.
Innovation Solution
A real-time method is developed to determine the acoustic velocities of P-waves, Rayleigh waves, and S-waves by measuring the times-of-flight of surface waves at critical angles, allowing for accurate calculation of acoustic velocities and probe separation without the need for calibration blocks or flaws in the test object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration blocks are used to measure acoustic velocity, then velocity measurement can be performed, but measurement precision deteriorates because calibration blocks are not exactly the same material as the test object
Solution Approach 1:
The test object itself serves as the measurement medium by utilizing its own surface waves. The method measures acoustic velocity directly in the test object material without requiring external calibration blocks, making the test object self-sufficient for velocity measurement. This eliminates the material mismatch problem between calibration blocks and test objects.
Solution Approach 2:
Surface waves act as an intermediary to transfer measurement information from the test object surface to the sensors. By measuring the propagation characteristics of surface waves along the surface, the method indirectly obtains bulk material velocity properties without direct contact with internal structures, enabling accurate velocity measurement in the actual test material.
2Productivity
If assumed sound velocity values are used in TFM imaging, then imaging can be performed, but image quality deteriorates due to sensitivity to velocity accuracy
Solution Approach 1:
The acoustic velocity is measured in advance using surface wave time-of-flight measurements before performing TFM imaging. This preliminary velocity determination ensures that the imaging process uses accurate, material-specific velocity values rather than assumed values, thereby improving image intensity accuracy while maintaining imaging productivity.
3Ease of operation
If probe distance is maintained by adjustable mechanical link, then probe positioning is flexible, but reliability deteriorates because the link length may be inadvertently changed
Solution Approach 1:
The system continuously monitors probe separation distance using surface wave time-of-flight measurements and provides feedback to confirm the mechanical link length remains correct. This real-time verification ensures that any inadvertent changes in link length are detected, maintaining reliable probe positioning while preserving operational flexibility.
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 method provides reliable and accurate acoustic velocity measurements and probe separation, enhancing the quality of TFM images by eliminating reliance on assumed velocities and ensuring precise inspection results, even in the presence or absence of weld caps.
Implementation Method 1
A ultrasonic probe 12, 14 is in acoustic contact with a test object 10... firing of a selected one of the elements of the ultrasonic probe 12, 14 generates a surface wave
Implementation Method 2
determining a time-of-flight of the surface wave... measuring the times-of-flight of surface waves at critical angles
Implementation Method 3
the time necessary to reach a reflector at a given distance from the probe... determining the acoustic velocity in the test object during the inspection
Data Source
AI summary
Disclosed is an ultrasonic non-destructive testing and inspection system and method for determining acoustic velocities in a test object. Beams of acoustic energy from firing an element of an emitting probe propagate in a first wedge, and a beam incident at the critical angle generates a surface wave in the test object. The surface wave propagates to a second wedge and signals are received at receiving elements of a receiving probe array. When a set of appropriate delays is applied to the receiving elements, the acoustic time-of-flight is the same to all receiving elements. Determination of the appropriate delays and the times-of-flight for P-type surface waves and Rayleigh surface waves enables computation of the P- and S-wave acoustic velocities in the test object. The time-of-flight measurement also enables computation of the separation between the first and second wedges.