Elastic cartilage mechanical properties

Mechanical properties of the knee components are derived from selected referred articles (See Table 1). Bone s density and its mechanical properties varied along its length, but in this study tibia and femur simplified as a non-linear isotropic material. Meniscus is composed of fibrocartilage, an anisotropic nonlinear viscoelastic material and its viscoelastic behavior make constant after 1500s [2]. Because an instance load applied in the dynamic analysis, so the properties variation is neglected. Articular cartilage and tibia plateau cartilage are assumed as isotropic elastic material. 

Some researchers have used approximate microscopic descriptions to develop more rigorous macroscopic constitutive laws. A microstructural model of AC [5] linked the directionality of mechanical stiffness of cartilage to the orientation of its microstructure. The biphasic composite model of [6] uses an isotropic fiber network described by a simple linear-elastic equation. A homogenization method based on a unit cell containing a single fiber and a surrounding matrix was used to predict the variations in AC properties with fiber orientation and fiber-matrix adhesion. A recent model of heart valve mechanics [8] accounts for fiber orientation and predicts a wide range of behavior but does not account for fiber-fiber interactions. 

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