Numerical Simulation to the Process of Damage Evolution of Defect Cartilage

Abstract

Objective To understand the stresses distribution and process of damage evolution of both matrix and fiber in the defect cartilage under load of compression. The numerical results may provide a reference to both of the design for cartilage alternatives and clinical repair of defect cartilage. Methods The thickness of different layers of cartilage was obtained by a kind of experiment, in which the displacement in different layers zone cartilage under the compression load was obtained by the digital correlation technique. The multi-layer cartilage model with fiber and defect was established by the multi-physics analysis software ANSYS, with the different layers of the cartilage refer to the experimental results. According to the strength condition, the cartilage damage evolution process was simulated by the method of modifying the stiffness of the elements. The influence of the different defect depth to the damage evolution of cartilage was considered in parameter study. Result The simulation results have shown that the stress distribution in matrix was related to the cartilage defect depth. The minimum stress was distributed in the deep areas and below the damage area, stress concentration was located in the both sides of the defect area in the cartilage matrix, and the damaged area developed gradually from surface to deep, the maximum stress located at both sides of defect area. The stress distribution of cartilage fibers related with their location, the compressive stresses are mainly distributed in the middle and deep area, which are greater than those of undamaged. Conclusion In the process of damage evolution, the damaged area gradually developed from the surface to the deep. In the case of defect value of 60%, the maximum equivalent stresses in matrix will be increased in the process of damage evolution; in the case of defect value of 5%, the maximum axial stresses in fibers will be increased in the process of damage evolution.