POROVISCOELASTIC DYNAMIC FINITE ELEMENT MODEL OF BIOLOGICAL TISSUE

Clinical evidences have demonstrated the important contribution of biomechanical factors to the behavior of soft tissues. Finite element analysis is used to study the mechanical behavior of biological tissue because it can provide numerical solutions to problems that are intractable to analytic solutions. This dissertation develops a finite element method that includes poro-viscoelastic material behavior, finite deformations, inertia and mechano-electrochemical effects for the modeling of biological tissue. The finite strains and inertial effects are introduced into the poroelastic model of biological tissues. Thus, the weak forms for the porous - electric-chemical model are developed by treating cation and anion as variables. Newmark-â method, the backward method, and Newton's method are incorporated into the implicit nonlinear solutions with the nearly incompressible and fully incompressible cases considered.This methodology and codes developed for the study have been verified with one -dimensional analytical solutions. Moreover, this study, using two dimensional examples, clearly demonstrates the importance of the finite deformation, the viscoelasticity of the material, and the electric-chemic effect. Finally, a preliminary work on the effect of impact loads on brain has show the capability of the present work in capturing sophisticated response behavior of the brain