Nonlinear Fe Analysis Of Hyperelastic Behavior For Biological Composite

Biological composites, including natural and artificial composites, exhibit nonlinear hyperelastic behavior. The present dissertation develops the micromechanical model and investigates behavior of the hyperelastic deformation for biological composite by using the nonlinear finite element method.(1) Basic theories, potential functions and hyperelastic constitutive relations of the hyperelastic materials are reviewed. Then, the nonlinear finite element equations based on these hyperelastic constitutive models are established, and solved by incremental Newton-Raphson method.(2) The hyperelastic deformation behavior of the biological soft tissues is studied. An inhomogeneous hyperelastic model for biological soft tissues with vascular inclusions is proposed for investigating the hyperelastic behavior of the biological soft tissues. The influence of the inclusions on the macroscopic behavior is studied in which the variable parameters are the thickness of the wall, the shear modulus and the interior diameter of blood vessel.(3) For artificial intervertebral disc, the hyperelastic deformation is studied. A hyperelastic plan-strain model is built for simulation of hyperelastic deformation behavior of artificial intervertebral disc under tension, compression and shear loadings.(4) The hyperelastic deformation behavior of the fiber reinforced polymer is studied. The fiber reinforced polymer has been widely used in replacement of human organs and tissues. The signal-fiber model and fiber bundle model are built. Furthermore, the influence of the fiber properties and volume fractions on the macroscopic behavior of the FRP is discussed. Then, a comparison between the macroscopic behaviors of signal-fiber composites and fiber bundle composites is investigated.It is shown that the hyperelastic model can describe the nonlinear behavior of the most of biological composites. The nonlinear finite element method based on the hyperelastic constitutive relations can effectively simulate the deformation of biological composites. The comparison between numerical results and experimental data shows the validity and effectiveness of the present methods and models. They can be extended to deformation smulation of the other materials which exhibit nonlinear hyperelastic behavior.