Resonant ultrasound is the study
of the fundamental behavior of solids using characteristics associated with
their vibration properties. This study has combined elements of free and
forced vibration theory of elastic, piezoelectric, and magnetoelectroelastic
media with an experimental measurement program to determine behaviors such
as the presence of flaws and the basic material properties of these elements.
Of primary interest are the regular shapes of spheres, cylinders, and parallelepipeds.
Our main computational tool is the Ritz method applied to these shapes,
although we sometimes resort to finite element models for some applications.
Layered systems and piezoelectric/magnetostrictive
solids are of particular current interest, as are materials with unusual
constitutive relations. Current examples of materials under study are the
elastic constants of cultured quartz, the vibration characteristics of trigonal
cylinders, and the effective elastic constants of finite laminated paralellepipeds.
Co-workers on this study
include Mr. Sudook Kim (NIST), Dr. Hassel Ledbetter (CU), Dr. Ward Johnson
(NIST), Dr. Ivar Reimanis (Colorado School of Mines), Dr. Fernando Ramirez
(Universidad de los Andes), and Professor Paul Heyliger. Past and current
funding of this work has been supplied by the National Science Foundatiuon,
NIST, the United States Department of Agriculture, and Storage Tech.