A DAMAGE MECHANISM OF MICRO-PARTICLES ON ARTICULAR CARTILAGE OF KNEE BY NANOINDENTATION

Articular cartilage plays an important role in organism due to its excellent shock absorbing and buffering functions. Increasing problems about damages of articular cartilage are making a great deal of trouble to human beings. The damage mechanism of articular cartilage is very complicated and keeps unclear. In this research, the damage mechanism was investigated from the perspective of micro-particle attrition by nanoindentation experiments. The micro-particle was simulated by the indenter in experiments. The experimental results demonstrated that the load from micro-particle could not maintain when water content was adequate. However, the load could maintain and increase after dehydration. It was found that the partial surface of articular cartilage was crushed and adhered to the indenter. The plastic energy was bigger than elastic energy in the nanoindentation process. Therefore, water content was the crucial factor to protect the articular cartilage from damage. And the recurring partial dehydration owing to ongoing compression enhanced the damage of micro-particle to articular cartilage. This research may provide a new understanding to the damage mechanism of articular cartilage.