The Finite Element Method For Chemo-Mechanical Coupling Behavior

Many smart materials, such as biology tissues and polymer gel, exhibit multi-field coupling behavior. Chemo-mechanical coupling is a relatively new problem whose theory does not been well established. Chemo-mechanical coupling behavior is investigated and modeled by using software ABAQUS in this dissertation. The research contents are as follows.1 A mass diffusion theory is reviewed. It is shown that concentration gradient, stress field and temperature field can cause mass diffusion.2 Swelling and deswelling behavior of ionic polymer subjected to an electrical field is investigated. Ionic diffusion equation in electrical field is obtained. Electro-chemo-mechanical coupling model is established for ionic polymer. It is shown that ions will be redistributed under the load of electrical field, which induces the swelling and deswelling.3 Full coupling behavior of chemo-mechanical problem is investigated. The equivalent integral form for coupling system of equilibrium equations, ionic diffusion equations and constitutive equations is obtained. User element subroutines are developed in ABAQUS for calculation. It is shown that mechanical and chemical fields interacts each other, and the deformation of solid skeleton is caused by the concentration variation; Both of the effective behaviors of solid skeleton and mass diffusion are changed because of coupling effect; Actually, the chemo-mechanical coupling behavior is a form of energy transformation between mechanical energy and chemical energy. Finally, energy in polymer will be balanced and mass conservation is also satisfied in this procedure.The present chemo-mechanical theory and numerical method can be applied to model chemo- mechanical coupling behavior of biology tissues, clays and so on.