北京生物醫(yī)學(xué)工程

編織支架彎曲變形時(shí)扁平現(xiàn)象的數(shù)值模擬研究

Numerical simulation of flattening phenomenon in braided stent during bending deformation

作者：付文宇李立新喬愛科

單位：北京聯(lián)合大學(xué)機(jī)器人學(xué)院(北京 100027) 北京工業(yè)大學(xué)環(huán)境與生命學(xué)部(北京100124)

關(guān)鍵詞：編織支架；有限元分析；扁平現(xiàn)象；數(shù)值模擬；參數(shù)分析

分類號(hào)：R318.01

出版年·卷·期（頁碼）：2020·39·5（455-461）

摘要：

目的編織支架通常用于介入治療腦動(dòng)脈瘤或動(dòng)脈狹窄。在彎曲變形時(shí)，編織支架有可能出現(xiàn)截面扁平現(xiàn)象。而在彎曲變形過程中保持其截面形狀不變，是編織支架實(shí)現(xiàn)介入治療療效的必要條件。因此，有必要對(duì)編織支架編織角、金屬絲根數(shù)、軸向長(zhǎng)度及名義直徑和扁平現(xiàn)象的關(guān)系進(jìn)行定量研究。方法首先使用參數(shù)化造型方法構(gòu)造具有不同的編織角度、金屬絲根數(shù)、軸向長(zhǎng)度和名義直徑的19個(gè)編織支架模型；然后對(duì)這些模型在純彎曲過程中的扁平現(xiàn)象用Abaqus / Explicit進(jìn)行計(jì)算分析；最后與實(shí)驗(yàn)數(shù)據(jù)進(jìn)行對(duì)比，驗(yàn)證有限元分析結(jié)果。結(jié)果力學(xué)計(jì)算表明編織角大于50?時(shí)扁平率小于0.0022；隨著彎曲角度的增大，扁平率也增大；編織角為60?或70?時(shí)，編織支架軸向長(zhǎng)度對(duì)扁平率基本沒有影響；編織角為50?時(shí)，支架軸向長(zhǎng)度增加，扁平率逐漸減小。編織角為30?，名義直徑從2 mm增加到5 mm，扁平率在0.26~0.46之間變化。編織角30?，軸向長(zhǎng)度35mm,支架金屬絲根數(shù)從12增加到48，扁平率從接近為0迅速增加到0.607。結(jié)論編織支架彎曲變形時(shí)扁平現(xiàn)象的數(shù)值模擬結(jié)果可以為臨床應(yīng)用中編織支架的結(jié)構(gòu)設(shè)計(jì)提供理論指導(dǎo)。

Objective Braided stent is usually used for interventional treatment of cerebral aneurysm or arterial stenosis. During the bending deformation, flattening phenomenon may occur. To achieve the therapeutic effect of the braided stent, a necessary condition is that its cross-sectional shape keeps unchanged during the bending deformation. Therefore, the quantitative effects of the braiding angle, the number of wires, axial length and nominal diameter on the flattening phenomenon of the cross section during bending deformation are studied. Methods Firstly， nineteen models of braided stent were constructed, which have different braiding angles, axial lengths，nominal diameter and the number of wires. Then the evaluation of flattening phenomenon was conducted using Abaqus / Explicit. Finally，the numerical results of finite element analysis were validated by comparison with the data of the experiment. Results The flattening ratio was less than 0.0022 when the braiding angle was greater than 50 degree; as the bending angle increased, the flattening ratio also increased; when the braiding angle was 60 degree or 70 degree, the axial length of the braided stent had almost no effect on the flattening ratio; when the braiding angle was 50 degree, the flatten ratio gradually decreased as the axial length of the stent increased. The braiding angle was 30 degree, the nominal diameter increased from 2mm to 5mm, and the flattening ratio varied from 0.26 to 0.46. The flatten ratio increased rapidly from close 0 to 0.607 as the number of wires increased from 12 to 48 (braiding angle was 30 degree and the axial length was 35 mm). Conclusions Numerical simulation of flattening phenomenon in braided stent during bending deformation can provide theoretical guidance for the structural design of braided stents in clinical applications.

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