Correction factor for contact radius in spherical indentation measurements
Résumé
A correction factor for applying previous method proposed by Collin et al. (2008) to indentation test with high strain rate is proposed in this paper. While the previous method allowed an accurate determination of the contact radius changes from the unloading stiffness and the elastic properties for a/R ratio lower than 0.25, the correction factor allows application of the method whatever the a/R ratio. It is shown that the proposed method is more accurate than methods using C-2 factor depending on plastic properties of the sample. Moreover, the proposed method is the only one to determine the contact radius changes during the unloading process. (C) 2012 Elsevier Ltd. All rights reserved.