不同截面和尺寸镁合金支架扩张过程中的应力变化

Stress change during the expanding process of magnesium alloy stents with different strut shapes and sizes

背景:降解带来的一个重要变化是支架尺寸的减小,从而影响支架的支撑力。由于支架的结构复杂性,导致其应力分布的复杂性。目的:分析不同截面形状和尺寸的镁合金支架在扩张过程中的应力变化。方法:利用有限元法分别计算正方形、八边形、圆形3种筋截面形状的镁合金支架扩张过程中主要受力部位的残余应力,同时计算120,140,160,180μm的4种不同尺寸下该处残余应力的变化情况。结果与结论:正方形、八边形、圆形这3种不同筋截面形状支架扩张后,圆形筋截面形状支架上主要受力部位的应力最大。对3种支架而言,随着筋截面尺寸的减小,该部位的应力减小,提示支架筋截面形状及尺寸均对支架扩张后的残余应力产生影响。

BACKGROUND：An important change of the degradation is the decreased size of the stents,thus affecting its support force.Due to the complexity of stent structure,stress distribution becomes complicated.OBJECTIVE：To analyze the stress change generated during the expansion of magnesium alloy stents at various strut shape and size.METHODS：Residual stress generated during the expanding process on cross-section stents with square,octagonal and circular strut was calculated by finite element method.Meanwhile,residual stress of different strut cross-section sizes （120,140,160,180 μm） was also calculated.RESULTS AND CONCLUSION：After the stent expanded,the stress generated in circular strut cross-section was the maximium,as for three kinds of stents,the stress decreased with the decline of cross-section size.Strut cross-section shape and size both have an effect on the residual stress generated during expanding process.