灌流载荷作用下软骨支架降解仿真研究

Numerical Analysis on Degradation of Cartilage Scaffold under Perfusion Loading

目的通过数值模拟研究灌流力学刺激对支架降解的影响,实现对降解程度的预测。方法基于灌流实验数据,利用Comsol建立流固耦合模型;采用ABAQUS软件建立支架有限元模型。基于这两种模型,模拟并预测支架的降解性能。结果通过流固耦合仿真发现,15.79 mL/min灌流速度对支架产生的初始压强为7.89 mL/min时的2倍,但沿着支架厚度方向从表面到底层,两者的压强逐渐减小且数值接近;将降解本构及有限元模型相结合,实现了支架结构降解过程的动态仿真,获得的降解趋势数据与实验规律基本相符,在第56天残余分子量可以达到0.643,与实验数据相比,模拟精度高于98%。结论灌流速度越大,支架受到的冲击压强越大;相同灌流速度下,支架表层的受力最大。建立的降解本构及有限元模型可以预测支架的降解规律。

Objective To study the effect of irrigation mechanical stimulation on scaffold degradation by numerical simulation,so as to predict its degradation degree.Methods Based on perfusion experimental data,the fluid-solid coupling model was established by Comsol.The finite element model of scaffold was established by ABAQUS.Based on the models,the degradation performance of scaffold was simulated and predicted.Results The fluid-solid coupling simulation showed that the initial pressure at the speed of 15.79 mL/min was two-fold of that at 7.89 mL/min.Along the thickness of scaffold from the surface to the bottom,the pressures between the two velocities were decreased and gradually close to each other.The degradation of scaffold structure could be simulated dynamically by combining the degradation constitutive model with the finite element model.The obtained degradation data were consistent with the experimental data,and the residual molecular weight reached 0.643 on the 56^(th) day.Compared with the experimental data,the simulation accuracy was higher than 98%.Conclusions The larger the perfusion velocity is,the greater the pressure on scaffold will be.Under the same perfusion velocity,the maximum force occurs on the surface of scaffold.The degradation pattern of scaffold can be predicted by applying the degradation constitutive model and the finite element model.