Testing For The Mechanical Properties Of Articular Cartilage And Finite Element Simulation

Articular cartilage is a kind of viscoelastic, nonlinear connective tissue, and the complexstructure and composition affects its unique mechanical properties. The mechanical propertiesof articular cartilage is widely concerned about, and it is important to test the mechanicalproperties of the cartilage detailedly for revealing the mechanism of the cartilage tissuemetabolism. It can also provide important basis for the treatment of diseases and clinicalcartilage repair and then promote the development of clinical cartilage disease research. Inthis paper, we use biological mechanics and engineering theory to reveal the change rule ofmechanical parameters in normal circumstances, our research is done with the aid of loadingdevices which designed by ourself, finite element simulation technology, Solidworksmodeling software and digital image correlation technology.To reveal the mechanical performance of articular cartilage, in this research we do theexperiment using digital image relevant technology which is advanced currently. Applyingcompressed, sliding and rolling load to fresh cartilage with loading devices and fixture whichdesigned by our own team in vitro which is similar to that in the body environment. Inexperiments we take effective measures to avoid the effect of boundary problem and mark thespot with nanoparticles in cartilage surface to analysis the whole and each layer’s change ofstress and strain in loading from the macroscopic and microscopic perspectives. We also usesimulation software of ANSYS to simulate compress and sliding load for explaining theresults from both theoretical and practical aspects.Research shows that, in direct compression, sliding and rolling loading, articularcartilage presents different mechanical characteristics, and its stress and strain valuechanges in different compression and loading speed. For its peculiar structure, mechanicalproperties between different layers differ greatly which changes obviously in surface layer,later the middle layer and the deep layer is stable. In addition, the load in vivo is continuous,in the experiment we find that strain value of the whole cartilage reduced during the loadingprocess of each time. This is the results of organization deformation and water transfer incartilage. Results of the experiment test are consistent with simulation analysis results, whichmake the theory and the practice to unity. They both reveal the unique mechanical propertiesof articular cartilage under loading.The methods and tools used in this study can be used in subsequent research as reference,information of the conclusion can provid basis for clinical disease of articular cartilage andsports health care research. It is helpful to the development of cartilage force biology.