The nonlinear model is studied to describe the mechanical behavior of the human knee meniscus tissue, which is composed of a solid phase, a fluid phase and also positive and negative charges. The model presents the theoretical formulation and the constitutive equations. Meniscal tissue consists primarily of a solid phase and a fluid phase. The fluid plays an important role in the mechanical behavior of the meniscus [1]. The mechanical description of the meniscus is also considered a combined action of the solid phase and the fluid phase [2]. The theoretical formulation and description of the model equations are presented. The challenge of describing the human knee meniscus in its complex inhomogeneous microstructure, which consists primarily of ionized water and collagen fibers embedded in an extracellular network of charged protein compounds. To describe the physiological behavior of the meniscus at the macroscale, the electrochemical-mechanical couplings between the components must be considered, as well as the anisotropic properties of the extracellular and viscoelastic matrix.
