Xin H, Shepherd Det, Dearn Kd
School of Mechanical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
Open Biomed Eng J. 2012;6:73-9. doi: 10.2174/1874230001206010073. Epub 2012 May 9.
This paper presents a theoretical analysis of the maximum contact stress and the lubrication regimes for PEEK (Polyether-ether-ketone) based self-mating cervical total disc arthroplasty. The NuNec(®) cervical disc arthroplasty system was chosen as the study object, which was then analytically modelled as a ball on socket joint. A non-adhesion Hertzian contact model and elastohydrodynamic lubrication theory were used to predict the maximum contact stress and the minimum film thickness, respectively. The peak contact stress and the minimum film thickness between the bearing surfaces were then determined, as the radial clearance or lubricant was varied. The obtained results show that under 150 N loading, the peak contact stress was in the range 5.9 - 32.1 MPa, well below the yield and fatigue strength of PEEK; the calculated minimum film thickness ranged from 0 to 0.042 µm and the corresponding lambda ratio range was from 0 to 0.052. This indicates that the PEEK based cervical disc arthroplasty will operate under a boundary lubrication regime, within the natural angular velocity range of the cervical spine.
本文对基于聚醚醚酮（PEEK）的自匹配型颈椎全椎间盘置换术的最大接触应力和润滑状态进行了理论分析。选择NuNec（®）颈椎间盘置换系统作为研究对象，将其解析建模为球窝关节。分别使用非粘着赫兹接触模型和弹流润滑理论来预测最大接触应力和最小油膜厚度。然后，随着径向间隙或润滑剂的变化，确定轴承表面之间的峰值接触应力和最小油膜厚度。所得结果表明，在150 N载荷下，峰值接触应力在5.9 - 32.1 MPa范围内，远低于PEEK的屈服强度和疲劳强度；计算得到的最小油膜厚度范围为0至0.042 µm，相应的lambda比范围为0至0.052。这表明，在颈椎自然角速度范围内，基于PEEK的颈椎间盘置换术将在边界润滑状态下运行。
