Integral-based formulations of viscoelasticity have been widely used to describe the mechanical behavior of soft biological tissues and polymers. However, it is suggested that they are not suitable to be used under high strain rates. On the other hand, strain-rate sensitive models with an explicit dependence on the strain-rate have been developed for a certain class of materials. They predict the viscoelastic behavior during ramp loading more accurately while fail to account for the relaxation response. In order to overcome these drawbacks, a viscoelastic constitutive model has been proposed in this study based on the concept of internal variables. While the behavior of elastic materials is uniquely determined by the current state of deformation or external variables, the mechanical response of inelastic materials are regulated also by internal variables. The internal variables are associated with the dissipative mechanisms in the material and along with the evolution equations introduce the effect of history of the deformation to the current configuration. The current study employs short-term and long-term internal variables to account for the viscoelastic response during loading and relaxation respectively.
Strain-Rate Sensitive Constitutive Modeling of Anisotropic Visco-Hyperelastic Materials
Ahsanizadeh, S, & Li, L. "Strain-Rate Sensitive Constitutive Modeling of Anisotropic Visco-Hyperelastic Materials." Proceedings of the ASME 2012 International Mechanical Engineering Congress and Exposition. Volume 8: Mechanics of Solids, Structures and Fluids. Houston, Texas, USA. November 9–15, 2012. pp. 747-748. ASME. https://doi.org/10.1115/IMECE2012-88608
Download citation file: