The effect of imperfections on acoustic wave propagation along a wedge waveguide

This is a note which describes the experimental results concerning the infl uence of defect of acuteness, such as edge milling burrs and truncation, on the dispersive behavior of acoustical wave trains transmitted through a ri ght angle wedge. It is observed that high frequency components propagate mo re slowly or more quickly than low frequency components according to the ki nd of defects which affect the edge of the wedge. The observed dispersive b ehavior may be explained qualitatively by considering that the sharp provid ing burrs act as a wedge with a depth-dependent apex angle. The other expla nation for the dispersion effect involves modeling the imperfections as rec tangular waveguides on a half semi-infinite medium. However this theoretica l approach does not agree with the experimental results qualitatively. (C) 1999 Elsevier Science B.V. All rights reserved.