Theoretical and Numerical Investigations of Swelling Phenomena of Hydrated Porous Media

生物材料(如硬组织和软组织)、人造材料(如水凝胶)或岩土材料(如粘土和页岩)的宏观行为是由微观上的多物理微结构、耗散现象和各种电化学-机械耦合决定的。此外，固体基质的非流动(固有)粘弹性性质与水力和电化学梯度引起的流动相关的粘性效应有很强的耦合。因此，我们得到了一个完全耦合的电化学-化学力学问题，包括膨胀，反之亦然，绝对有限变形时的收缩现象。基于多孔介质理论(TPM)，本项目的目标是给出固液集合体的理论和数值描述的适当公式，其中负电荷固定在固体骨架上，正离子和负离子包含在孔隙流体中。这个项目与我们的荷兰合作伙伴Jacques Huyghe博士提出的热邻近建议密切相关，其创新之处在于建立了水化固体绝对有限三维粘弹性变形下完全耦合的电化学-化学-力学模型的理论公式，以及基于有限元工具PANAS的有限元框架下的多相模型的数值处理。

The macroscopic behaviour of biomaterials like hard and soft tissues, artificial materials like hydrogel or geomaterials like clay and shale ist governed by the multiphysic microstructure together with dissipative phenomena and various electrochemomechanical couplings on the microscale. Furhtermore, flowindependent (intrinsic) viscoelastic properties of the solid matrix are strongly coupled with the flow-dependent viscous effects resulting from hydraulic and electrochemical gradients. Thus, one obtains a fully coupled electro-chemomechanical problem including swelling and, vice versa, shrinking phenomena at absolutely finite deformations. Based on the Theory of Porous Media (TPM), it is the goal of this project to deliver a proper formulation of both the theoretical and the numerical description of a solid-fluid aggregate, where negative charges are fixed to the solid skeleton and positive and negative ions are includetd into the pore-fluid. The innovation of the this project which is closely related to a thermatically neighboured proposal by our Dutch partner Dr. Jacques Huyghe lies in both the theoretical formulation of a fully coupled electro-chemomechanical model at absolutely finite 3-dimensional viscoelastic deformations of the hydrated solid and the numerical treatment of the multiphasic model in the framework of the FEM based on the FE tool PANDAS.