Biomechanical Modeling Of Articular Bone And Cartilage In Virtual Operation System Of Hip Joint

Through analyzing studys on the biomechanical model of articular bone and articular cartilage from a large number of scholars,advantages and disadvantages of various models were summarized.In addition,combined with the characteristics of virtual surgery system,the paper establishes reasonable biomechanical models for bone and cartilage respectively which meet the requirements of virtual operation of hip joint.In this paper,the model of articular bone describes the inhomogeneous properties based on the linear relationship between the CT values at each point which can be obtained from images and the corresponding apparent densities at the point.For realizing the anisotropy properties of bone material,the anisotropic elastic constitutive relation used in finite element method developed from Hooke’s Law was introduced and then deduced to the form of engineering constants.In the processes of validate experiment,three-dimension finite element volume mesh model was read into MATLAB and the availability of biomechanical model of bone built in this paper was proved by bringing the vitro biomechanical experimental results to contrast.In virtue of the idea derived from composite cylinder applied in composite material theory,the biomechanical model of articular cartilage was established.The effective stiffness of each basic structural unit was related to microstructural information observed with LSCA and constitute materials(collagen and proteoglycan matrix)properties according to research results by Hill and his co-worker.Then substitute the material properties patameters in effective stiffness of fibre phase with a viscoelastic constitutive relation,and the model of cartilage associated with time and minimal-invasive-derived microstructure information was obtained.A reasonable design and concrete steps for validate experiment of cartilage biomechanic model are carried out in this paper,also the explanation for how to impement.Although the errors in both contrasting experiment are large,in the condition where errors can’t be avoided,they will be acceptable.