Abstract: To investigate the microscopic mechanical behavior of articular cartilage with different compressive rates by combining experiment and simulation. A finite element model was built based on fibril-reinforced porous elastic model, where proteoglycan and interstitial fluid were considered as two phase and non-linear spring elements SPRINGA played the part of collagenous fibers. The experimental data was used to determine the relevant parameters of the finite element model and the rate-dependent properties of different layers were analyzed by using ABAQUS. It is found that the compressive strain of superficial layer is the largest, the compressive strain of deep layer is the smallest and the compressive strain of middle layer is between the superficial and deep zones under constant loading rate. The compressive strains of different layers increase with increase of loading rate. At the initial stage, fluid flows out mainly in the superficial zone, while fluid gradually flows into middle and deep layers with the increasing time and the position of maximum flow moves downward. The fibril reinforced poroelastic model based on experiment is created successfully. The mechanical properties of different layers in articular cartilage are rate-dependent. The liquid phase plays a key role in bearing load and the flow of liquid in cartilage under load leads to the exchange of nutrients in cartilage.

Key words: compressive rate, mechanical property, ABAQUS, articular cartilage, different layers