Finite element analysis on the mechanical behavior of articular cartilage under rolling load

Objective: The normal displacement, pore pressure and strain of different layers for articular cartilage were obtained with different compressive strains and rolling rates by finite element simulation method. Methods: The fibril reinforced poroelastic model of cartilage was built by considering depth-dependent elastic modulus, initial void ratio, permeability of strain and collagen fiber. By utilizing ABAQUS software, the finite element analysis on mechanical behavior of articular cartilage under the condition of rolling load was conducted. Results: With time continues, the normal displacement of different layers for cartilage tends to increase firstly and then decrease under rolling load. The normal displacement of superficial layer is largest, middle layer is smaller and deep layer is smallest. The normal displacement of different layers increases with the increment of compressive strain, however the changing tendency is not obvious with different rolling rates. Strain of superficial is largest while it decreases gradually with depth increasing. The pore pressure of different layers for articular cartilage increases with the increment of compressive strain while the pore pressure decreases along cartilage depth from surface to deep layer. Conclusions: It is found that the normal displacement and strain vary with different layers for articular cartilage under rolling load. The change of normal displacement of different layers is different with compressive strain and rolling rates. The paper acquires the pore pressure changes, which is hard to obtain by the experiment. The study contributes to the evaluation on the mechanical properties of cartilage with more accuracy and is significant for articular cartilage disease treatment and cartilage defect repair.