This study develops a computational model of the braided stent for interpreting the mechanism of stent flattening during deployment into curved arteries. Stent wires are expressed using Kirchhoff's rod theory and their mechanical behavior is treated using a corotational beam formulation. The equation of motion of the braided stent is solved in a step-by-step manner using the resultant elastic force and mechanical interactions of wires with friction. Examples of braided-stent deployment into idealized arteries with various curvatures are numerically simulated. In cases of low curvature, the braided stent expands from a catheter by releasing the bending energy stored in stent wires, while incomplete expansion is found at both stent ends (ie, the fish-mouth phenomenon), where relatively little bending energy is stored. In cases of high curvature, much torsional energy is stored in stent wires locally in the midsection of the curvature and the bending energy for stent self-expansion is not fully released even after deployment, leading to stent flattening. These findings suggest that the mechanical state of the braided stent and its transition during deployment play an important role in the underlying mechanism of stent flattening.

中文翻译：

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用于解释支架展平机制的编织支架展开计算模型

本研究开发了一个编织支架的计算模型，用于解释支架在部署到弯曲动脉期间变平的机制。支架线使用 Kirchhoff 的杆理论表示，并且它们的机械行为使用 corotational 梁公式处理。编织支架的运动方程使用合成的弹性力和线与摩擦的机械相互作用逐步求解。数值模拟了将编织支架部署到具有各种曲率的理想动脉中的示例。在低曲率的情况下，编织支架通过释放储存在支架线材中的弯曲能量从导管膨胀，而在储存相对较少弯曲能量的支架两端发现不完全膨胀（即鱼嘴现象）。在高曲率的情况下，支架线材在曲率中段局部储存了大量的扭转能，支架自展的弯曲能即使在展开后也没有完全释放，导致支架扁平化。这些发现表明，编织支架的机械状态及其在展开过程中的转变在支架展平的潜在机制中起重要作用。