Murphy B P, Savage P, McHugh P E, Quinn D F
National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland.
Ann Biomed Eng. 2003 Jun;31(6):686-91. doi: 10.1114/1.1569268.
Coronary stents are used to re-establish the vascular lumen and flow conditions within the coronary arteries; the typical thickness of a stent strut is 100 microm, and average grain sizes of approximately 25 microm exist in stainless steel stents. The purpose of this study is to investigate the effect of strut size on the stress strain behavior of 316 L stainless steel. Other materials have shown a size dependence at the micron size scale; however, at present there are no studies that show a material property size dependence in coronary stents. Electropolished stainless steel stent struts within the size range of 60-500 microm were tensile tested. The results showed that within the size range of coronary stent struts a size dependent stress-strain relationship is required to describe the material. Finite element models of the final phase of fracture, i.e., void growth models, explained partially the reason for this size effect. This study demonstrated that a size based stress-strain relationship must be used to describe the tensile behavior material of 316 L stainless steel at the size scale of coronary stent struts.
冠状动脉支架用于重建冠状动脉内的血管腔和血流状况；支架支柱的典型厚度为100微米，不锈钢支架中存在平均粒径约为25微米的晶粒。本研究的目的是研究支柱尺寸对316L不锈钢应力应变行为的影响。其他材料在微米尺寸尺度上已显示出尺寸依赖性；然而，目前尚无研究表明冠状动脉支架的材料性能存在尺寸依赖性。对尺寸范围在60 - 500微米的电解抛光不锈钢支架支柱进行了拉伸试验。结果表明，在冠状动脉支架支柱的尺寸范围内，需要一种尺寸依赖的应力应变关系来描述该材料。断裂最后阶段的有限元模型，即孔洞生长模型，部分解释了这种尺寸效应的原因。本研究表明，必须使用基于尺寸的应力应变关系来描述冠状动脉支架支柱尺寸尺度下316L不锈钢的拉伸行为材料。
