The resonant ultrasound spectroscopy method for determining the Poisson׳s ratio of spheres over the full range

• A method for determining the Poisson׳s ratio of isotropic spheres was provided via resonant ultrasound spectroscopy (RUS) for the full range (−1 to +0.5).
• The steel, SiO2, re-entrant copper foam, pure Indium and 13.5 wt% In–Sn alloy spheres were prepared and the Poisson׳s ratios of them were determined experimentally via RUS.
• Experimental measurements were compared with the numerical results, and good agreement was found between the measurements and predictions.
• The effects of slight deviation in shape from an ideal sphere are analyzed for various Poisson׳s ratios.

The method for determining the Poisson׳s ratio of isotropic spheres was studied via resonant ultrasound spectroscopy (RUS). To that end, The mode structure maps for freely vibrating isotropic spheres were obtained via finite element method over the full range of Poisson׳s ratio (−1 to+0.5). RUS measurements for spherical samples (indium, steel, SiO2, 13.5 wt% In–Sn, and copper foam) were compared with the numerical results and the Poisson׳s ratios were determined as +0.4, +0.3, +0.2, −0.08, and −0.3, respectively. The effects of slight shape imperfection upon the first 12 modes were analyzed for various Poisson׳s ratios, and were found to be negligible in interpretation of the experimental results.