Two Studies in Evanescent Wave Propagation (Beam, Acoustic, Gaussian)

Two problems are studied in this dissertation. In the first problem, surface motion, excited by acoustic emissions produced by fracture processes at the edge of a buried, penny-shape crack, are investigated. First, wave-front approximations to the emissions generated by the sudden growth of a tensile crack in the unbounded elastic solid are reviewed. These approximations are then Fourier transformed to give the high-frequency portion of their spectra. Second, time- and frequency-domain approximations to the surface motions excited by this growing crack, when it is buried in a half-space, are calculated. These results are then scrutinized to elucidate what part of the signals measured at the surface carry information about the crack's size, its orientation, and the fracture processes near the crack-tip.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Theoretical and Applied Mechanics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Pott, John

• Applied Mechanics

Identifier

(UMI)AAI8422800

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/71676