A linear viscoelastic biphasic model for soft tissues based on the theory of porous media

Based on the Theory of Porous Media (mixture theories extended by the conce pt of volume fractions), a model describing the mechanical behavior of such as articular cartilage is presented. As usual, the tissue will be modeled as a materially incompressible binary medium of one linear viscoelastic por ous solid skeleton saturated by a single viscous pore-fluid. The contributi on of this paper is to combine a descriptive representation of the linear v iscoelasticity law for the organic solid matrix with an efficient numerical treatment of the strongly coupled solid-fluid problem. Furthermore, deform ation-dependent permeability effects tire considered. Within the finite ele ment method (FEM), the weak forms of the governing model equations tire set tip in a system of differential algebraic equations (DAE) in time. Thus, a ppropriate embedded error-con trolled time integration methods can be appli ed that allow for it reliable and efficient numerical treatment of complex initial boundary-value problems. Tile applicability and the efficiency of t he presented model are demonstrated within canonical, numerical examples, w hich reveal the influence of the intrinsic dissipation on the general behav ior of hydrated soft tissues, exemplarily on articular cartilage.