This paper presents a review of recent work by us and others on the scattering of elastic waves from simple defects in solids. The emphasis in the report is on the representation in the time-domain as contrasted to that in the frequency-domain, although both aspects are discussed. The defects are principally small voids ranging in shape from spherical voids to simulated flat cracks with combinations of these, such as a double void and a void surrounded by a flat crack. The defects were produced in Ti-alloy by the diffusion bonding process and were typically about 1 mm in extent. The scattered radiation pattern was probed in the 1<ka<4 range using conventional transducers and electronics. Upon capture, the scattered waveforms were digitized and processed in a Data General M 600 laboratory computer in which the usual Fourier transform and deconvolution processes were executed. An additional feature, emphasizing the time-domain aspect, was the capability to determine the impulse response function from the experimental data. The results show that careful evaluation of the time-domain results, even before extensive signal processing, form an invaluable guide to the characterization of a simple flaw, which is the object of advanced techniques in NDE.
All Science Journal Classification (ASJC) codes
- Modeling and Simulation
- Physics and Astronomy(all)
- Computational Mathematics
- Applied Mathematics