| ABSTRACT: | ELECTROMAGNETIC-RESONANCE-ULTRASOUND MICROSCOPY (ERUM) FOR
QUANTITATIVE EVALUATION OF LOCALIZED ELASTIC CONSTANTS OF SOLIDS
J. Tian, O. Hirotsugu, T. Toyokazu, H. Masahiko
Osaka University, Osaka, Japan
This paper presents a new acoustic-resonance microscopy, electromagnetic-resonance- ultrasound
microscopy (ERUM), to evaluate localized elastic constant of a solid material. It is based on the resonance-
frequency shift of a vibrating oriented langasite (La3Ga5SiO14) crystal contacting the specimen via a sphere
tip. The vibration of langasite is excited and detected by a dynamic electric field from a sorrounding
solenoid coil. Thus, the acoustic coupling between the oscillator and specimen is made only through the tip,
isolating the oscillator from any other contacts. (They may otherwise obscure the effect of point contact with
specimen and annihilate the quantitative evaluation.) Selection of a vibration mode that is sensitive to
Young’s modulus of specimen is achieved by a calculation using the Rayleigh- Ritz method. On the basis of
the calibration for the specimen’s contact effective stiffness, the local elastic stiffness is determined from
resonance-frequency shifts of the oscillator. As an illustrative example, the distribution of Young’s modulus
of an SCS-6 SiCf/Ti-6Al-4V composite is presented.
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