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Ultrasonic attenuation of a void-containing medium for very long wavelengths
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Yuece, H. Lee, S. S. Williams Jr., J. H. |
| Copyright Year | 1983 |
| Description | Ultrasonic longitudinal through-thickness attenuation in an isotropic medium due to scattering by randomly distributed voids is considered analytically. The attenuation is evaluated on the assumption of no interaction between voids. The scattered power is assumed to be entirely lost, thus accounting for the ultrasonic attenuation. The scattered power due to the presence of a void is described in terms of the scattering cross section of the void. An exact solution exists for the scattering cross section of a spherical void. An approximate solution for the scattering cross section of an ellipsoidal void is developed based on the so-called Born approximation commonly used in quantum mechanics. This approximate solution is valid for k sub p a sub i 1, where k sub p is the wave number of the incident longitudinal wave and a sub i is the largest dimension of the void. It is found that the shape of the void has negligible effect on the scattering cross section and that only the volume of the void is important. Thus, it is noted that in cases where k sup p a sub i 1, the exact scattering cross section of a spherical void having the same volume as an arbitrarily shaped void can be used for evaluating ultrasonic attenuation. |
| File Size | 1285137 |
| Page Count | 22 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19830020195 |
| Archival Resource Key | ark:/13960/t9b61dg9d |
| Language | English |
| Publisher Date | 1983-06-01 |
| Access Restriction | Open |
| Subject Keyword | Nondestructive Tests Scattering Cross Sections Acoustic Scattering Spheres Ellipsoids Born Approximation Voids Isotropic Media Plane Waves Longitudinal Waves Mathematical Models Ultrasonic Radiation Acoustic Attenuation Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
