Digital ultrasonics for materials science
Migliori, Albert National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico.
Suzuki, Yoko National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico.
Betts, Jonathan B. National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico.
Fanelli, Victor National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico.
- Measurements of resonances
- Measurements of time of flight
- Links to Primary Literature
- Additional Readings
The parameters that measure the resistance to compression and resistance to shear of a solid are called elastic moduli and, together with density, determine two observables: the speed of propagation of stress waves (some of which are sound waves, some of which are shear waves) and the mechanical resonances. Resonances are most easily understood by thinking of the ringing of a bell. The tones produced by the bell are determined by the shape of the bell and the material from which it is made. Generally, if the shape is known, the tones of the bell can be used to determine the elastic moduli, or stiffnesses, of the material, and vice versa. Through the elastic stiffnesses, the wave speeds and resonances provide a measure of two fundamental thermodynamic quantities: internal energy and free energy. Unlike most of the properties used to characterize condensed matter, the elastic moduli are tensors (there can be up to 21 different moduli) containing a wealth of detail that provide one of the most revealing probes of solids. Elastic moduli also determine the frequencies of low-frequency phonons. Phonons are the quanta of vibration in solids. They can be thermally excited, and contribute to the internal energy and heat capacity. A phonon is a resonance; the lowest-energy phonons have wavelengths that approach the size of a specimen and are measured directly by resonance ultrasound methods. Because of the connections to fundamental thermodynamic properties, ultrasound measurements in condensed matter are so important that hundreds of useful approaches have been developed.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information