MULTI-PHYSICS ANALYSES OF ARTICULAR CARTILAGE AND SUBCHONDRAL BONE BY USING MICRO-CT AND MPM MEASUREMENT BASED MODEL

摘要

The articular cartilage and subchondral bone are modeled by using μ-CT and MPM measurement results for multi-physics analyses, which employed the conventional finite element code for the solid continuum and particle method - SPH- for the liquid continuum. The articular cartilage at the micro-scale consists of the chondrocyte, the extracellular matrix-collagen fiber, the proteoglycan and the intercellular fluid and modeled by using MPM observation results. The subchondral bone consists of the trabecular bone and the intercellular fluid, and these are modeled by using μ-CT measurement results. Both are remodeled by the cyclic stress caused by the joint movement such as walking and jogging. Especially, the flow of intercellular fluid causes the shear stress on the chondrocyte cell in the articular cartilage and on the bone cell in the trabecular bone. Therefore, the flow and stress analyses of both the articular cartilage and subchondral bone are strongly required. In this study, the multi-physics analyses combined with finite element and particle methods are carried out to investigate the stress stimulation on the chondrocyte cell and the surface of trabecular bone. For the solid phase analyses by using finite element code, the nonlinear viscoelastic constitutive model was introduced for collagen fiber, the elastic model for the trabecular bone. For the fluid phase analyses by using SPH code, the viscosity model was introduced for intercellular fluid.