复合材料支架的仿生界面设计与有限元优化方法

Biomimetic Interface Design and Finite Element Optimisation for Osteochondral Composite Scaffold

研究光固化成形复合材料支架的材料界面分层问题。以关节软骨下骨板为仿生对象，提出骨软骨复合材料支架的界面结构仿生设计与优化方法。在构建关节软骨下骨板表面孔隙结构模型（面孔隙率为6．7土0．71％，孔隙分布夹角为40°-50°或80-90°）的基础上，建立PEGDA／β-TCP软骨复合支架的仿生界面结构模型和有限元分析模型。结合多目标优化方法确定影响骨体孔隙成形性及其与软骨层分层的关键参数为孔隙直径、结构单元（三边形、四边形、六边形）、孔隙间距（边长）、面孔隙率；确定具有四边形结构单元，面孔隙率为5％-15％，孔隙尺寸为不小于400μm的界面结构具有良好的骨体孔隙结构成形性和较好的界面材料结合能力。该方法为复合材料支架仿生结构设计与制造一体化的研究提供新的评估与预测手段。

A method of biomimetic interface design and multi-objective optimisation is presented for the aim of preventing the interfacial delamination of composite scaffolds for the osteochondral tissue engineering application. The engineering structure model （6.7±0.71% of surface porosity and 40°-50° or 80°-90° of distribution angle） is firstly established from the surface characterization of subchondral bone plate, following the biomimetic interface model and finite element models of the osteochondral composite assembled by PEGDA hydrogel chondral compound and β-TCP ceramic bone compound fabricated using laser stereolithography and ceramic sintering techniques. Combined with multi-objective optimisation approach, the parameters, that is, the diameter of pore, structural unit （triangular, quadrilateral or hexagonal unit）, pore spacing （or side length）, surface porosity, are identified as playing an important role in the pore formibility and interracial delamination between the PEGDA hydrogel and [3-TCP ceramic compound of osteochondral composite. The optimized interracial structure is defined as having the charactizations of quatrilateral unit, surface porosity in a range of 5%-15%, pore diameter of more than 400 μm, which having a better capability both to achieve pore formibility and to prevent delamination. The method discussed in this paper provides a promise assessment way to integrate biomimetic design with rapid manufacturing of composite scaffold.