Open AccessAn alumina standard reference material for resonance frequency and dynamic elastic moduli measurement. I. For use at 25 C
Author(s) -
R. W. Dickson,
J. B. Wachtman
Publication year - 1971
Publication title -
journal of research of the national bureau of standards. section a. physics and chemistry
Language(s) - English
Resource type - Journals
eISSN - 2376-5704
pISSN - 0022-4332
DOI - 10.6028/jres.075a.016
Subject(s) - resonance (particle physics) , materials science , torsion (gastropod) , bar (unit) , shear modulus , torsion spring , flexural strength , young's modulus , composite material , modulus , acoustic resonance , elasticity (physics) , physics , atomic physics , classical mechanics , medicine , surgery , meteorology
Bars of sintered polycrystalline alumina were machined to nominal dimensions of 12.7 by 1.27 by 0.32 cm. Surfaces were machined flat and parallel. The mass, dimensions, and resonance frequencies (flexural and torsional) were measured at 25 °C. The exact frequency is specified for each bar and is typically about 2030 Hz for flexural resonance and 11250 Hz for torsional resonance. The effect of suspension loading on resonance frequency was determined and a correction made. Each bar can be used as a frequency standard with an uncertainty for values measured in air of about ±0.03 Hz for flexure and ±0.08 Hz for torsion. The effect of atmosphere on resonance frequency was determined and a correction was made for this effect. The uncertainty for resonance frequencies in vacuum is about ±0.06 Hz for flexure and ±0.18 Hz for torsion. Each bar can also be used as a dynamic elasticity standard with an uncertainty estimated to be about 0.2 percent for the shear modulus and 0.4 percent for Young's modulus.