Model for analyzing the mechanical behavior of articular cartilage under creep indentation test

摘要

In this study, an innovative depth dependent biphasic transversely isotropic model (DBT) was proposed to study the mechanical behavior of Articular Cartilage (AC). To find a more precise model to address the mechanical behavior of AC, the vital role of collagen fibers in all zones of the AC has been taken into account and depth dependent elasticity mechanical properties of cartilage are calculated as a function of collagen fibers orientation and volume fraction. Material parameters of permeability function were calculated in such a way that the variations of indenter displacement with time predicted by Finite Element Method (FEM) simulation for creep indentation test of the AC sample based on DBT model. In addition, the test was simulated by an isotropic-biphasic model to compare the capabilities of these two models and difference in mechanical behaviors of biphasic-isotropic and depth dependent transversely isotropic materials. According to the calculations, the presence of collagen fibers triggers increasing of stresses in fibers direction and decreasing of stresses perpendicular to fiber direction in the superficial and deep zones of AC. The findings of this study may have implications not only for calculating stress distributions in AC components but also for developing progressive damage model of AC for predicting osteoarthritic cartilage behavior in different cartilage-related diseases.