Constitutive Formulation of the Mechanical Properties of Synthetic Hydrogels

Abstract

This study attempts to define a universal description of the constitutive formulation of mechanical properties of synthetic hydrogels that can be manufactured as load-bearing structures to replace diseased or damaged soft tissues. While the strain energy density function (SEF) describing the elastic properties of a soft tissue generally depends on two invariants, we propose a SEF that depends on only the first strain invariant. This allows quantifying the SEF from data of a uniaxial extension test. The single invariant SEF was used to predict the mechanical response of a thick-walled tube inflated by an internal pressure. The results show excellent concordance with recorded experimental data, indicating that the mechanical properties of elastic hydrogels can be accurately represented by a SEF that is an exponential function of the first strain invariant with two material constants.

Poro-viscoelastic constitutive modeling of unconfined creep of hydrogels using finite element analysis with integrated optimization method

“…Nonlinear elastic models such as hyperelasticity were initially applied to characterize the rubberlike mechanical response of hydrogels (Rachev et al, 2004;Swieszkowski et al, 2006). Elastic models cannot account for the viscoelastic responses of hydrogels observed experimentally.…”

A Study on the Effects of Covered Stents on Tissue Prolapse

“…Polyvinyl alcohol cryogels are assumed to be incompressible, isotropic, homogeneous, and elastic [36]. A 20% PVA formulation was selected based on previous experience [12], This material was also modeled with the Mooney-Rivlin model of Eq.…”