Ultrasonic Surface Wave Crystallographic Orientation Measurement
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Solution Overview
Problem
Existing ultrasonic defect inspection methods for anisotropic materials, such as single crystal or directionally solidified metals, face challenges in accurately determining crystallographic orientation due to low signal-to-noise ratios when using conventional detector arrays, which hinders reliable defect inspection, especially in situations where access to both sides of the object is limited.
Innovation Solution
The method involves specifying a minimum distance between the ultrasonic transducer and the closest detector in the array, ensuring the minimum time of flight for the Rayleigh wave is greater than the sum of the maximum time of flight for the longitudinal surface wave and the pulse duration, thereby improving signal-to-noise ratio and allowing accurate crystallographic orientation measurement using an ultrasonic surface wave pulse comprising both longitudinal and Rayleigh waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional detector arrays are used to measure ultrasonic surface waves, then the measurement can be performed with simple equipment, but the signal-to-noise ratio is low and the measurement accuracy is poor
Solution Approach 1:
The patent applies preliminary action by pre-determining the minimum distance d_min before performing the measurement. This distance is calculated based on the pulse duration and wave velocities to ensure that the Rayleigh wave signal arrives after the longitudinal surface wave has completely decayed. By setting this minimum distance in advance, the measurement system is prepared to avoid signal overlap and noise contamination, thereby improving the signal-to-noise ratio and measurement accuracy of crystallographic orientation.
2Measurement precision
If the detector is placed close to the transducer to improve measurement resolution, then the measurement precision improves, but the signals overlap and noise increases
Solution Approach 1:
The patent applies parameter changes by modifying the spatial parameter (distance between transducer and detector) to its minimum acceptable value d_min. This distance is precisely calculated based on the pulse duration and wave velocity parameters. By changing the distance parameter to this optimized minimum value, the system achieves the best possible measurement resolution while ensuring that the Rayleigh wave signal does not overlap with the longitudinal surface wave, thereby eliminating signal interference and noise.
3Ease of operation
If ultrasonic surface wave method is used to enable single-face access measurement, then the ease of operation improves, but the signal-to-noise ratio deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the distance parameter d_min between the transducer and detector. This parameter is calculated based on the pulse duration and wave velocities to ensure that the Rayleigh wave signal arrives after the longitudinal surface wave has completely decayed. By setting this optimized distance parameter, the system maintains the ease of single-face access operation while significantly improving the signal-to-noise ratio, making the measurement reliable and accurate.
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 enhances the accuracy of crystallographic orientation measurement and defect inspection in anisotropic materials by improving signal resolution and reducing noise, enabling reliable detection of defects in materials like nickel-based alloys used in gas turbine engines.
Implementation Method 1
using an ultrasonic transducer to generate an ultrasonic surface wave pulse in the surface of the object, the ultrasonic surface wave pulse having a pulse duration (tw) and comprising a longitudinal surface wave and a Rayleigh wave
Implementation Method 2
measuring a time of flight of a surface wave generated by the transducer between the transducer and each detector of the array
Data Source
Figure 1a~1b
Figure 2~3
Figure 4
AI summary
A method of measuring a crystallographic orientation (X, Y, Z) of an object (10) using an ultrasonic transducer (22) and a detector array (24) comprising a plurality of ultrasonic detectors (26). The method comprises: • determining a minimum distance (dmin) between the transducer (22) and the detector (26a) of the detector array (24) closest to the transducer (22); • placing the transducer (22) and the detector array (24) in contact with a surface (14) of the object (10) such that the transducer (22) and the detector (26a) of the detector array (24) closest to the transducer (22) are separated by at least the minimum distance (dmin); • using the transducer (22) to generate an ultrasonic surface wave pulse in the surface (14) of the object, the ultrasonic surface wave pulse having a pulse duration (tw) and comprising a longitudinal surface wave (32) and a Rayleigh wave (34); and • measuring a time of flight of a surface wave generated by the transducer (22) between the transducer (22) and each detector (26) of the array (24) to determine the crystallographic orientation (X, Y, Z) of the object (10). The minimum distance (dmin) is the distance at which the minimum time of flight of the Rayleigh wave (tR) is at least the sum of the maximum time of flight of the longitudinal surface wave (tL) and the maximum pulse duration (tw).