动物医用铁磁软导丝的分段磁化及变形分析

Segmentation magnetization and deformation analysis of ferromagnetic soft guidewire for veterinary medicine

介入式医疗技术已被广泛用于动物医疗,为畜牧业发展和保护濒危野生动物发挥了越来越重要的作用。由于需要适应不同物种的复杂血管结构,需要新型的导丝以满足微型化和灵活化的需求。在各种新型导丝中,最具有潜力的是基于硬磁软材料的铁磁软导丝(ferromagnetic soft guidewire,FSG),已被证明非常适用于在微小的非结构化环境中的生物医学操作,可以很好地适应各种动物的血管组织尺度。本研究中,基于硬磁软材料的力学模型,进行了均匀磁化和分段磁化的FSG在磁场下的有限元仿真分析。对于均匀磁化的FSG,以导丝的长度、磁场模式为变量,得到了不同长度的FSG在不同磁场下的仿真变形结果。仿真和实验的一致性验证结果表明有限元仿真的可靠性和有效性,对于实现FSG在特定作业中的正确转向具有指导意义。在此基础上,根据硬磁软材料的变形规律,对FSG进行分段的磁化模式设计,以实现其在磁场下的预定义变形形态。有限元仿真结果表明所设计的分段磁化FSG可以很好地复现预定义变形,为进一步推进FSG的形状可编程性研究及在生物医学领域的应用提供了重要参考。

Interventional medical technology has been widely used in animal medicine,playing an increasingly important role in the development of animal husbandry and the protection of endangered wild animals.Due to the complex vascular structures of different species,novel guidewires are required to meet the demands of miniaturization and flexibility.Among different new guidewire types,the most promising is the ferromagnetic soft guidewire(FSG)based on hard-magnetic soft materials,which have been proven to be well adapted to the scale of vascular tissue in various animals.Here,based on the mechanical model of hard-magnetic soft materials,finite element simulation analysis of uniformly magnetized FSG and segmented-magnetized FSG under magnetic fields was performed.For a uniformly magnetized tip,the length of the guidewire and the magnetic field mode were set as variables to obtain the simulation deformation results of the FSG with different lengths under different magnetic fields.The consistency verification results of simulation and experiments showed the reliability and validity of the finite element simulation,which has guiding significance for realizing the correct steering of the FSG in specific operations.On this basis,according to the deformation law of hard-magnetic soft materials,the FSG with a segmented magnetization pattern were designed to achieve its predefined deformation morphology under a magnetic field.The finite element simulation results showed that the segmented magnetized FSG could reproduce the predefined deformation well,which provides an important reference for further promoting the shape programmability of FSG and its application in the biomedical field.