Аннотация:Identification of the nonlinear Maxwell-type viscoelastoplastic model using stress-strain curves at constant stress rates
А.V. Khokhlov
Lomonosov Moscow State University, Institute of mechanics, Moscow, Russia
E-mail: andrey-khokhlov@ya.ru
General properties of stress-strain curves produced by the physically non-linear constitutive equation with two arbitrary material functions under loadings at constant stress rates are studied analytically in uni-axial case. The analysis reveals several attributes of the theoretic stress-strain curves that can be utilized as the model applicability indicators which are convenient for experimental check. An effective identification technique is developed using test stress-strain curves of a material. It is proved that only two loading tests with different stress rates are required to evaluate an array of material functions values at arbitrarily chosen points in stress domain. The explicit expressions are derived for the material functions values via given stress rates and magnitudes of strain measured in the tests. They enable separate and direct evaluation of the material functions values without error accumulation. A specific rapid procedure is developed for the model identification in the class of power material functions depending on four material parameters. A number of additional applicability indicators are found for the power model employing characteristic features of test stress-strain curves.