Advances in modelling saturated soft biological tissues and chemically active gels

作者：Ehlers Wolfgang; Acartuerk Ayhan; Karajan Nils^*

来源：Archive of Applied Mechanics, 2010, 80(5): 467-478.

DOI：10.1007/s00419-009-0386-y

• Theory of Porous Media (TPM)
• Coupled problems
• Swelling
• Soft biological tissue
• Biomechanics
• Electro-active polymer

Swelling-active materials are numerous and can be found in many applications regarding geotechnical, biological or chemical problems. In general, these materials consist of a charged solid skeleton which is saturated by a fluid mixture containing a solvent and one or more dissolved electrolytes. Following this, the swelling mechanism can either be triggered via changes of the solute concentration in the surrounding solution or by the application of an electric field. Due to the complex micro structure and the numerous coupled effects which result from the electro-mechanical coupling, this class of materials is very effectively described using the Theory of Porous Media. In this regard, the present paper will provide a brief overview of the involved mixture kinematics, the balance equations, as well as the necessary constitutive theory. The presented model is then brought into a weak formulation which is suitable for a numerical treatment using the Finite Element Method. The chosen degrees of freedom are the solid displacement, the ion concentrations, the pressure and the electrical potential, which are discontinuous over the domain boundary. These discontinuities lead to stability problems which can be solved by a penalty method. Finally, two representative examples are presented addressing a free swelling experiment of a cylindrical nucleus pulposus specimen, as well as an electrically initiated bending of a cantilever made of an electro-active polymer like hydrogel, for instance.

• 出版日期2010-5