Prof. Keppens










Veerle Keppens
Dept. Materials Science & Engineering
401A Ferris Hall
Knoxville,TN 37996

ph.: 865 974 3494
fax: 865 974 4115



Welcome to the Resonant Ultrasound Spectroscopy Group

Professor Keppens's research group focuses on the characterization of novel materials using Resonant Ultrasound Spectroscopy (RUS). RUS is an effective technique for determining the elastic moduli of solids, based on the measurement of the resonances of a freely vibrating body. 

principles of RUS
The mechanical resonances can be calculated for a sample with known dimensions, density, and elastic tensor.  In a RUS experiment, the mechanical resonances of a freely vibrating solid of known shape are measured, and an iteration procedure is used to “match” the measured lines with the calculated spectrum.  This allows determination of all elastic constants of the solid from a single frequency scan, which clearly indicates a main advantage of RUS: there is no need for separate measurements to probe different moduli, and multiple sample remounts and temperature sweeps are avoided.  The sample is lightly held between two transducers, eliminating bonding agents that can be particularly bothersome at low temperatures.  Another advantage lies in the ability of RUS to work with small samples.  Whereas conventional techniques can demand a sample-size up to a centimeter, RUS measurements can be made on mm-sized samples.