Theory of elastic wave scattering: Applications of the method of optimal truncation

Abstract

Discrete variational quantum reactive scattering method with optimal distorted waves. I. Theory

Strong Scatterers and 1-D Born Inversion

“…The far field impulse response function given for a void in Titanium [5] is shown as Figure 1. An al ternative model, based on MOOT has been provided by Opsal and Visscher [6] and this gives results which are almost identical to those shown as Figure 1. Time doma in r e sponse for a spherical void in Tit anium [5].…”

Ultrasonic Signal Characterizations of Flat-Bottom Holes in Titanium Alloys: Experiment and Theory

“…One such plane-wave solution, the method Qf Qptimallruncation (MOOT) [4], is particularly suitable for our FBH study. This method expresses the plane-wave solution in terms of series expansion truncated optimally in the least-squares sense.…”

Elastic Wave Scattering by Arbitrarily Shaped Voids

“…The results were compared with the MOOT backscatter solution [3] . Sample comparisons for a variety of frequencies and polar angles are given in 6 give results for an axisymmetric shape which is known as "Mickey Mouse" to the NDE community.…”

“…However, numerical evaluations of scattering amplitudes have generally been restricted to idealized fl aw shapes and , t o our knowledge , no scheme to calculate scattering amplitude s of arbitrary shape has ever been implemented in 3D. Volumetric shapes with an axis of symmetry have been examined with T-matrix and MOOT [2,3] but the axisymmetric limitation precludes a large portion of all expected flaw shapes. Furthermore, a quasi-plane wave assumption is often made.…”