Microstructure Modeling And Performance Study Of Bionic Bones

With the development of bone tissue engineering and rapid prototyping technology,tissue-engineered bone scaffolds constructed by seed cells,biological factors and biomimetic scaffolds had become the most effective way to treat large-scale bone defects,and the establishment of personalized biomimetic scaffolds to meet the needs of different cases was the core of bone tissue engineering.At present,there were still many problems in designing and manufacturing bone scaffolds with appropriate bionic degree,biological activity and mechanical properties.In the field of bone tissue engineering,this paper took the bionic scaffold used in the clinical operation experiment and planning as the research object,and carried out a series of research work,such as the construction of the internal microstructure model of the bionic scaffold and the evaluation of the internal microstructure performance of the scaffold,aimed at the optimization of the mechanical properties.The main research contents were as follows:(1)The internal micro pore structure model of bionic scaffold was constructed by using constraint optimization and genetic algorithm.Used the ellipsoid as the basic unit,the negative model of the pore structure was established.The problem of solving the optimization model was transformed into the mathematical model of solving the nonlinear constrained optimization problem,and the improved genetic algorithm was used to solve and optimize the model automatically.In the aspects of convergence,global and local optimization,self-adaptive,the algorithm was designed comprehensively to improve the performance and efficiency of the algorithm.(2)Based on the analysis of the factors that affect the performance of micro pore structure,it was proposed that the porosity,pore distribution uniformity,pore size uniformity and connectivity rate of the scaffold should be taken as the criteria to evaluate the performance of the internal structure of the scaffold.Based on the geometric characteristics of the negative micro pore model,the calculation methods of each evaluation index were designed.Accorded to the influence degree of each index on the comprehensive performance of scaffold,the weight coefficients of each parameter were determined by PCA method,and the objective optimization function was established.(3)The data format of the negative pore structure model and the overall support model were determined,and the operations of file output,repair,reconstruction and Boolean operation of the negative model were completed.The negative model was transformed into the overall support model.The samples of the solid model of the scaffold were prepared by SLA,and the mechanical strength tests were carried out systematically,and the mechanical properties parameters of the scaffold model were obtained.CAE simulation analysis of the whole model of mandible was carried out.The results showed that the bionic scaffold has good mechanical properties.