Remote characterization of surface slots by enhanced laser-generated ultrasonic Rayleigh waves
Jing Xiao1, Jian Chen2, Xudong Yu3
1School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore; Institute of High Performance Computing, A*STAR (Agency for Science, Technology and Research), Singapore 138632, Singapore.
Ultrasonics
|October 12, 2021
Summary
This study introduces a laser-based ultrasonic method to measure long surface slots. The technique accurately determines slot length using Rayleigh waves without needing slot orientation or width details.
Area of Science:
- Materials Science
- Non-Destructive Testing
- Acoustics
Background:
- Surface feature characterization is critical for industrial applications, particularly for features with large depths, high aspect ratios, or those under extreme conditions.
- Current methods may face limitations in characterizing such features, especially in non-contact scenarios or harsh environments.
Purpose of the Study:
- To present a novel non-contact method for characterizing surface slots with large lengths using laser-generated ultrasonic Rayleigh waves.
- To demonstrate the feasibility and accuracy of this method through numerical simulations and experimental validation.
- To investigate the impact of mode conversion on reconstruction accuracy.
Main Methods:
- Generation of ultrasonic Rayleigh waves using a pulsed laser.
- Application of a delay-and-sum superposition technique to enhance the signal-to-noise ratio of transmitted Rayleigh waves.
- Calculation of slot length from Rayleigh wave time-of-flight data, independent of orientation, width, or aspect ratio.
Main Results:
- The proposed method successfully characterizes surface slots with large lengths.
- Numerical simulations and experiments confirm the method's excellent performance.
- Analysis of mode conversion provides insights into reconstruction accuracy.
Conclusions:
- The laser ultrasonic technique offers a simple and feasible approach for rapid characterization of surface slots.
- This non-contact method is suitable for assessing normal and angled features with high aspect ratios, even in extreme environments.
