Most of the micro-components, such as coronary stents, consist of an oligo-crystalline micro-structure. This means that the detection of the few coarse grains which are columnar and parallel to the longitudinal ingot axis is possible. The deformation behavior of such micro-structures is obviously different from polycrystalline materials, since the anisotropic properties of one grain, in relation to its nearest neighbors should be considered. The goal of this study is the simulation of the crack initiation process under a cyclic loading situation in the oligo-crystalline micro-structure of the stent component made of X2CrNiMo-18-15-3. The crack initiation process is simulated employing the physically-based Tanaka-Mura model implemented in Finite Element Method (FEM). The available experimental result data have also been used as the input parameters to the current modelling approach. In this regard the grain size and the grain orientation are changed, and their effect together with the influence of the surface roughness on the fatigue life of the stent components has been studied.

大多数微组件，例如冠状动脉支架，由寡晶微结构组成。这意味着可以检测少量的柱状且平行于纵向锭轴的粗晶粒。这种微结构的变形行为明显不同于多晶材料，因为应该考虑一个晶粒相对于其最近邻晶粒的各向异性特性。本研究的目的是模拟由 X2CrNiMo-18-15-3 制成的支架组件的寡晶微结构在循环加载情况下的裂纹萌生过程。裂纹萌生过程采用有限元法 (FEM) 中基于物理的 Tanaka-Mura 模型进行模拟。可用的实验结果数据也被用作当前建模方法的输入参数。在这方面，晶粒尺寸和晶粒取向发生了变化，并且研究了它们的影响以及表面粗糙度对支架部件疲劳寿命的影响。