颅内动脉支架的疲劳强度
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摘要
目的分析颅内动脉支架疲劳强度与连接体长度的关系,探究支架发生疲劳断裂的准确位置。方法采用疲劳断裂的有限元分析方法对3种脑动脉支架进行疲劳寿命分析,并运用Goodman曲线绘制支架疲劳危险点分布图。基于美国材料与实验学会F2477-07标准,对3种支架的疲劳寿命进行测试。结果支架连接体长度越长,支架危险点最大等效应力和平均应力越大,危险点分布越接近疲劳极限曲线,支架更容易发生疲劳断裂。Goodman疲劳极限曲线表明,3种血管支架在体内10年的使用时间里是安全的。有限元分析与实验结果表明,支架结构连接点附近区域疲劳寿命较低,支架危险点位于连接处的圆弧部位。结论血管支架有限元分析的技术合理可行,有限元分析结果与实验数据基本吻合。在支架结构设计时,可以减少连接体的长度,从而提高支架的使用寿命。
Objective To analyze the relationship between fatigue strength and connector length of intracranial artery stents,so as to investigate the exact location of fatigue fracture for the stent. Methods The fatigue life for 3 kinds of artery stents were analyzed by finite element analysis method of fatigue fracture,and distribution map of dangerous points was drawn by means of Goodman curve. Based on F2477-07 standard from American Society for Testing and Materials( ASTM),the fatigue life for 3 kinds of stents was tested. Results If the length of the support connector was longer,the maximum equivalent stress and the average stress in dangerous points of the stent would be larger. If the distribution of dangerous points was more close to the curve of fatigue limit,and fatigue fracture was more likely to occur in the stent. Goodman curves indicated that 3 kinds of stents was safe to be used in the body for ten years. Finite element analysis and experimental result showed that fatigue life near the stent junction was relatively lower,and dangerous points of the stent was located at the arc junction. Conclusions It is reasonable to study stents by finite element analysis,whose results are basically coincided with the experimental data. Fatigue life can be extended by reducing connector's length for the design of stent structure.
Objective To analyze the relationship between fatigue strength and connector length of intracranial artery stents,so as to investigate the exact location of fatigue fracture for the stent. Methods The fatigue life for 3 kinds of artery stents were analyzed by finite element analysis method of fatigue fracture,and distribution map of dangerous points was drawn by means of Goodman curve. Based on F2477-07 standard from American Society for Testing and Materials( ASTM),the fatigue life for 3 kinds of stents was tested. Results If the length of the support connector was longer,the maximum equivalent stress and the average stress in dangerous points of the stent would be larger. If the distribution of dangerous points was more close to the curve of fatigue limit,and fatigue fracture was more likely to occur in the stent. Goodman curves indicated that 3 kinds of stents was safe to be used in the body for ten years. Finite element analysis and experimental result showed that fatigue life near the stent junction was relatively lower,and dangerous points of the stent was located at the arc junction. Conclusions It is reasonable to study stents by finite element analysis,whose results are basically coincided with the experimental data. Fatigue life can be extended by reducing connector's length for the design of stent structure.
引文
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[10]冯海全,何平基,胡志勇.球囊扩张式冠脉支架的弯曲疲劳寿命[J].机械设计与研究,2013,29(2):36-39.
[11]李红霞,张艺浩,王希诚.基于有限元模拟的支架扩张、血流动力学及支架疲劳分析[J].医用生物力学,2012,27(2):178-185.LI HX,ZHANG YH,WANG XC.Analysis of stent expansion,blood flow and fatigue life based on finite element analysis[J].J Med Biomech,2012,27(2):178-185.
[12]RAMESH V,MARREYA,ROBERT B,et al.Fatigue and life prediction for cobalt-chromium stents:A fracture mechanics analysis[J].Biomaterials,2006,27(1):1988-2000.
[13]NAKAZAWA G,ALOKE VF,MARC V,et al.Incidence and predictors of drug-eluting stent fracture in human coronary artery[J].J Am Coll Cardiol,2009,54(21):1924-1931.
[2]石更强,宋晓冰.基于ANSYS软件血管支架的有限元分析[J].生物医学工程学杂志,2015,32(5):1004-1008.
[3]SIANOS G,HOFMA S,LIGTHART JMR,et al.Stent fracture and restenosis in the drug-eluting stent era[J].Catheter Cardio Inte,2004,61(1):111-116.
[4]ASTM Standard F2477 07.Standard test methods for in vitro pulsatile durability testing of vascular stents[S].2007.
[5]田文彦,陈庆福.冠脉支架用Co-Cr合金L605管材的特性[J].材料科学与工艺,2007,15(6):797-780.
[6]郭飞飞,冯海全,江旭东.球囊扩张式冠脉支架耦合扩张变形机理研究[J].机械设计与研究,2012,28(3):30-37.
[7]冯海全,胡志勇,江旭东.冠脉支架用CoCr合金的弹塑性变形行为[J].塑性工程学报,2012,19(4):108-112.
[8]张洪辉,冯海全,刘佳.血管支架柔顺性能的仿真模拟及灰色相关性分析[J].医用生物力学,2016,31(3):206-212.ZHANG HH,FENG HQ,LIU J.Simulation on flexibility o vascular stents and grey correlation analysis[J].J Med Biomech,2016,31(3):206-212.
[9]张瑞敏,冯海全,陈彦龙,等.基于有限元分析的冠脉支架疲劳强度研究[J].机械设计与制造,2013,2(2):268-271.
[10]冯海全,何平基,胡志勇.球囊扩张式冠脉支架的弯曲疲劳寿命[J].机械设计与研究,2013,29(2):36-39.
[11]李红霞,张艺浩,王希诚.基于有限元模拟的支架扩张、血流动力学及支架疲劳分析[J].医用生物力学,2012,27(2):178-185.LI HX,ZHANG YH,WANG XC.Analysis of stent expansion,blood flow and fatigue life based on finite element analysis[J].J Med Biomech,2012,27(2):178-185.
[12]RAMESH V,MARREYA,ROBERT B,et al.Fatigue and life prediction for cobalt-chromium stents:A fracture mechanics analysis[J].Biomaterials,2006,27(1):1988-2000.
[13]NAKAZAWA G,ALOKE VF,MARC V,et al.Incidence and predictors of drug-eluting stent fracture in human coronary artery[J].J Am Coll Cardiol,2009,54(21):1924-1931.