Application of the singularity expansion method to elastic wave scattering

Journal Article · Mon Oct 01 04:00:00 EDT 1990 · Applied Mechanics Reviews; (United States)

OSTI ID:6101480

Ueberall, H ^[1]; Delsanto, P P ^[2]; Alemar, J D; Rosario, E ^[3]; Nagl, A ^[4]

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1. Univ. of America, Washington DC (United States)
2. Dipt. di Fisica del Politecnico, Torino (Italy)
3. Univ. of Puerto Rico, Mayaguez (Puerto Rico)
4. Pailen-Johnson Associates, Vienna, VA (United States)

The singularity expansion method (SEM), established originally for electro-magnetic-wave scattering by Carl Baum, has later been applied also to acoustic scattering. In the present paper, the authors describe further applications of this method of analysis to the scattering of elastic waves from cavities or inclusions in solids. They first analyze the resonances that appear in the elastic-wave scattering amplitude, when plotted vs frequency, for evaluated or fluid-filled cylindrical and spherical cavities or for solid inclusions. These resonances are interpreted as being due to the phase matching, ie, the formation of standing waves, of surface waves that encircle the obstacle. The resonances are then traced to the existence of poles of the scattering amplitude in the fourth quadrant of the complex frequency plane, thus establishing the relation with the SEM. The usefulness of these concepts lies in their applicability for solving the inverse scattering problem, which is the central problem of Nondestructive Evaluation (NDE). Since for the case of inclusions, or of cavities with fluid fillers, the scattering of elastic waves gives rise to very prominent resonances in the scattering amplitude, it will be of advantage to analyze these with the help of the resonance scattering theory or RST. These resonances are caused by the proximity of the SEM poles to the real frequency axis, on which the frequencies of physical measurements are located. A brief history of the establishment of the RST is included here immediately following the Introduction.

• OSTI ID: 6101480
• Journal Information: Applied Mechanics Reviews; (United States), Journal Name: Applied Mechanics Reviews; (United States) Vol. 43:10; ISSN 0003-6900; ISSN AMREA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420500* -- Engineering-- Materials Testing
ACOUSTIC TESTING
CAVITIES
CYLINDERS
DATA ANALYSIS
ELASTIC SCATTERING
INELASTIC SCATTERING
MATERIALS TESTING
NONDESTRUCTIVE TESTING
RESONANCE SCATTERING
SCATTERING
SOLIDS
SPHERES
STANDING WAVES
TESTING
WAVE PROPAGATION