基于离散单元法的人工骨材料微观结构研究

Research on Artificial Bone Material Microstructure Based on Discrete Element Method

人工骨支架的孔隙率是影响体液在人工骨内部循环和细胞在内部生长能力的重要参数.利用离散单元法分析人工骨支架制备过程中羟基磷灰石微球的堆积过程,根据每一时刻各颗粒间的相互作用计算接触力,再运用牛顿第二定律计算单元的运动参数,从而实现对运动情况的预测.在颗粒的碰撞过程中,运动的颗粒必然趋于稳定,最终计算出稳定状态下人工骨支架的孔隙率和配位数.利用掺杂可溶解生物微球的方法调节人工骨支架的孔隙率和配位数,对人工骨支架孔隙率进行控制,实现了按照个体差异制备人工骨支架.对比前人晶格理论计算人工骨孔隙率的方法,验证了晶格理论的可行性,同时也体现了离散单元法的准确性.

The porosity of an artificial bone scaffold is an important parameter that evaluates the nutrition fluid seepage and the bone cell ingrowth capability in the patient body. The Hydroxyaptite （HA） microsphere accumulation process in fabricating the bone scaffold is analyzed using the discrete element approach; Contact force is calculated according to interaction among microspheres at every moment of the whole process; And the motion parameters are calculated based on the Newton＇s second law of motion to describe all the HA microspheres falling and their moving curve. The porosity and coordination number of artificial bone scaffold are finally calculated as the colliding microspheres being stable during the fabrication stage. Required porosity and coordination number of biological artificial bone scaffold are regulated by using doped soluble microsphere process. Compared with the former calculated results by the feasible lattice theory, the discrete element method is validated and proves more accurate than the lattice theory in calculating porosity of porous material.