Development of Dispersion Curves for Two-Layered Cylinders Using Laser Ultrasonics
Publication Name: Journal of the Acoustical Society of America
In this paper, laser-ultrasonic techniques are employed to develop a quantitative understanding of the underlying principles of the propagation of guided circumferential waves in two-layered cylindrical components. The high-fidelity, broad-bandwidth, point source/receiver and noncontact nature of these optical techniques are critical elements to the success of this work. The experimental procedure consists of measuring a series of transient, circumferentially propagating waves in a cylindrical waveguide and then operating on these transient waveforms with signal-processing techniques to develop the dispersion relationship for that waveguide; this procedure extracts the steady-state behavior from a series of transient measurements. These dispersion curves are compared to theoretical values. There is good agreement between the experimental and theoretical results, thus demonstrating the accuracy and effectiveness of using laser-ultrasonic techniques to study the propagation of guided circumferential waves.