抄録
Articular cartilage provides joints with low friction and wear resistance essential for repetitive gliding motion and shock absorption, while evenly spreading the applied load onto the underlying bone. Mechanical factors are strongly implicated in the development of osteoarthritis, although the exact mechanisms are still not known. To aid in understanding whether mechanical factors are primary or secondary in the evolution of the degeneration of joint, knowledge of the contact stress distribution on the joint surface is needed. In this study, the static stress distribution on the surface of contact of two rigid spheres coated with elastic layers is estimated utilizing a mechanical model to simulate a diarthrodial joint. The problem is equivalent to the mixed boundary-value problem of the three-dimensional theory of elasticity. The dual integral equations are reduced to infinite systems of simultaneous equations by using the technique of expanding the normal contact stress with infinite series. The exact and complete analytical solution of contact stress is obtained. Numerical results are obtained with indication of the effect of the cartilage layer thickness, elastic modulus, Poisson's ratio and joint conformity on the contact stress distribution.
