3D打印TPU气道支架的有限元仿真分析及其力学性能

3D printing of TPU airway stent and finite element simulation analysis and its mechanical properties

气道支架的可压缩性直接影响手术操作,植入后与气道的相互作用力对临床疗效影响大,开展支架植入气道的力学性能仿真分析可为产品研发和临床应用提供参考。采用计算机软件构建气道支架3D模型,以热塑性聚氨酯弹性体为打印材料,熔融沉积3D打印制备挤出率和壁厚不同的气道支架,采用万能试验机测试其支撑力、压缩强度和压缩弹性缩量,对支架植入气道狭窄简化模型中的受力情况进行有限元仿真分析。随着径向压缩率增大,支架的压缩强度和径向支撑力呈上升趋势,压缩弹性模量呈现下降趋势;随着打印挤出率的增大,支架中丝材堆积更紧密,压缩弹性模量、压缩强度和径向支撑力均呈上升趋势。有限元仿真分析结果表明,随着壁厚增加,支架变形困难,产生的支撑力增大;随着狭窄率的增加,支架所受压迫力增大,应力集中与支架变形能力、气道狭窄情况密切有关。

The compressibility of airway stent directly affects surgical operation,and the interaction force between the implanted stent and the airway has a significant impact on clinical efficacy.Simulation analysis on mechanical performance after stent implantation in the airway can provide reference for product development and clinical application.3D models of airway stents were constructed by using computer software,and airway stents with different extrusion rates and wall thicknesses were fabricated with thermoplastic elastomers as printing material by melt deposition 3D printing.The support force,compressive strength,and compressive modulus were tested by using a universal testing machine,and the stress situation in the simplified model of airway stenosis after stent implantation was analyzed through finite element simulation.As the radial compression ratio increases,the compression strength and radial support force of the stents show an upward trend,while the compression modulus shows a downward trend.As the printing extrusion rate increases,the silk material in the stent is stacked more tightly,and the compressive modulus,compressive strength,and radial support force all show an upward trend.The result of finite element simulation analysis shows that as the wall thickness increases,the deformation of the stent becomes difficult,and the generated support force becomes greater.As the stenosis rate increases,the compressive force on the stent increases,and stress concentration is closely related to the deformation ability of stent and the condition of airway stenosis.