A POROELASTIC FINITE-ELEMENT FORMULATION INCLUDING TRANSPORT AND SWELLING IN SOFT-TISSUE STRUCTURES

A field theory is presented for the study of swelling in soft tissue s tructures that are modeled as poroelastic materials. As a first approx imation, soft tissues are assumed to be linear isotropic materials und ergoing infinitesimal strains. Material properties are identified that are necessary for the solution of initial boundary value problems whe re swelling and convection are significant. A finite element model is developed that includes the solid displacements, the relative fluid di splacements, and a representative concentration as the primary unknown s. A numerical example is presented based on a triphasic model. The fi nite model simulates a typical experimental protocol for soft tissue t esting and demonstrates the interaction and coupling associated with r elative fluid motion and swelling in a deforming poroelastic material. The theory and finite element model provide a starting point for nonl inear porohyperelastic transport-swelling analyses of soft tissue stru ctures that include finite strains in anisotropic materials.