Aachen Institute for Advanced Study in Computational Engineering Science (AICES), RWTH Aachen University, Templergraben 55, 52056, Aachen, Germany.
CNRS, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 61 Avenue du Général de Gaulle, 94010, Créteil Cedex, France.
Biomech Model Mechanobiol. 2020 Jun;19(3):1091-1108. doi: 10.1007/s10237-019-01272-9. Epub 2020 Jan 8.
Cementless implants are widely used in orthopedic and dental surgery. However, debonding-related failure still occurs at the bone-implant interface. It remains difficult to predict such implant failure since the underlying osseointegration phenomena are still poorly understood. Especially in terms of friction and adhesion at the macroscale, there is a lack of data and reliable models. The aim of this work was to present a new friction formulation that can model the tangential contact behavior between osseointegrated implants and bone tissue, with focus on debonding. The classical Coulomb's law is combined with a state variable friction law to model a displacement-dependent friction coefficient. A smooth state function, based on the sliding distance, is used to model implant debonding. The formulation is implemented in a 3D nonlinear finite element framework, and it is calibrated with experimental data and compared to an analytical model for mode III cleavage of a coin-shaped, titanium implant (Mathieu et al. in J Mech Behav Biomed Mater 8(1):194-203, 2012). Overall, the results show a close agreement with the experimental data, especially the peak and the softening part of the torque curve with a relative error of less than 2.25%. In addition, better estimates of the bone's shear modulus and the adhesion energy are obtained. The proposed model is particularly suitable to account for partial osseointegration.
无骨植入物在骨科和牙科手术中被广泛应用。然而，在骨-植入物界面仍会发生脱粘相关的失效。由于对骨整合现象的了解仍然有限，因此很难预测这种植入物失效。特别是在宏观尺度上的摩擦和粘附方面，缺乏数据和可靠的模型。本工作旨在提出一种新的摩擦公式，可以模拟骨整合植入物与骨组织之间的切向接触行为，重点是脱粘。经典的库仑定律与状态变量摩擦定律相结合，以模拟位移相关的摩擦系数。基于滑动距离的平滑状态函数用于模拟植入物脱粘。该公式在三维非线性有限元框架中实现，并使用实验数据进行校准，并与用于硬币形状钛植入物的 III 型劈裂的解析模型进行比较（Mathieu 等人在 J Mech Behav Biomed Mater 8(1):194-203, 2012）。总体而言，结果与实验数据非常吻合，尤其是扭矩曲线的峰值和软化部分，相对误差小于 2.25%。此外，还可以更好地估计骨的剪切模量和粘附能。所提出的模型特别适合于考虑部分骨整合。
