@Article{cmc.2009.010.243,
AUTHOR = {B  Keerthika, Y P  Cao, D  Raabe},
TITLE = {Mechanical Characterization of Viscoelastic-Plastic Soft Matter Using Spherical Indentation},
JOURNAL = {Computers, Materials \& Continua},
VOLUME = {10},
YEAR = {2009},
NUMBER = {3},
PAGES = {243--258},
URL = {http://www.techscience.com/cmc/v10n3/22466},
ISSN = {1546-2226},
ABSTRACT = {In this study, effects of the plastic deformation and the time-dependent deformation behavior on the fundamental relations in the Oliver & Pharr method are studied by using finite element analysis based on a viscoelastic-plastic model developed for polymers. The study eventually yields an experimental protocol and using which, the instantaneous modulus of the viscoelastic-plastic materials may be reliably determined. Experiments have been performed on four polymers to verify the conclusions from the numerical analysis.},
DOI = {10.3970/cmc.2009.010.243}
}