Abstract
The research described in this thesis uses broadband laser generation and detection techniques to investigate acoustic wave propagation in wedge type structures. The interrogating waves were generated by a Q-switched ND:YAG laser. Fizeau based interferometry, accomplished with a constant wavelength (CW) Argon laser, was used to detect the waveforms. The experimental study was designed to examine the propagation of thermoelastically generated Lamb and Rayleigh waves in plates with ramp-like changes in thickness. The structures to be studied consist of six thin (I mm) copper plates which ramp up into a thicker section (12.86 mm). The angles of these ramps range from 150 to 90' at 15' intervals. Relationships were found between wave characteristics and the geometric aspects of the plate. Changes in frequency spectra and phase of the interrogating wave were used to identify parameters essential to the non-destructive evaluation of these specimens.
Uzzell, Christopher Tinsley (1994). The characterization of Lamb and Rayleigh waves in plates with ramp-like changes in thickness. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1994 -THESIS -U99.