Objective:To study the stress distribution of the femoral hip prosthesis after the hip joint replacement.Methods:After the hip joint replacement,when the femur and prosthesis are considered as concentric cylinders with perfectly banded interface,a relatively perfect theoretical model of simulating the interfacial stress transfer is established.Results:The maximum interfacial shear stress occured at Z=0.At the cross-section of the femoral neck,interfacial shear stress decreased exponentially with the increases of the Z.Shear stress became very small at Z>0.1 m,which meant that the shear stress at the far end of the femoral hip prosthesis was very small.In order to avoid the stress concentration and femoral hip prosthesis sinking,interfacial stress must remain constant and balanced with the pressure load at Z=0.The radius of the femoral hip prosthesis changed with interfacial shear stress.The maximum value of the radius occured at Z=0,then it decreased at m.Specially,a=18.2 mm at Z=10 mm,a=5.36 mm at Z=98 mm,these are ideal radius.Conclusion:A theoretical model of simulating the interfacial stress is established when the femur and prosthesis are considered as concentric cylinders.The distributions of the interfacial shear and radial stresses with the axial positions are obtained.A theoretical reference for the design of the prosthesis is provided.
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