多平面锥形针接触建模与影响因素研究

Study on Contact Model and Influencing Factors of Multiplanar Pyramid Needle

针对平面锥形针在组织接触变形阶段受力变化难以分析的现状,根据弹性组织与针接触时的变形特点,建立了多平面锥形针的接触模型,并重点探讨了该阶段针的受力与穿刺性能问题。接触模型揭示了在穿刺深度相同的情况下,锥形针的接触受力受组织剪切模量、针形半顶角和针的平面数三个因素共同影响。通过实验对接触模型进行验证,发现实验曲线和理论曲线能够较好地吻合,表明该模型是有效可行的。由研究可得:为减小平面锥形针的接触受力、提高针的穿刺性能,可选择较小剪切模量的组织、减小针形半顶角或减少针的平面数。

Considering the difficulties in analyzing multiplanar pyramid needle＇s force at the tissue＇s contact stage,a multiplanar pyramid needle＇s contact model was derived,which was based on the deformation between needle and tissue,and the problems of contact force and the puncturing performance was emphatically discussed.The model indicated that the contact force of the multiplanar pyramid needle was influenced by three factors,tissue＇s shear modulus,needle＇s half-apex angle and the number of needle＇s surfaces.The contact model was validated by the experiments and the experimental curves are in good agreement with theoretical data,which indicates the model is accurate and effective.According to the research results,in order to reduce the contact force and improve the puncturing performance of needle during the contact stage,it is a wise choice to select smaller tissue shear modulus,decrease needle＇s half-apex angle or the number of needle＇s surfaces.