Faculty of Computer Science and Biomedical Engineering, Institute of Biomechanics, Graz University of Technology, Graz, Austria.
Biomedical Engineering Department, King's College London, London, United Kingdom.
PLoS One. 2020 Jun 24;15(6):e0234340. doi: 10.1371/journal.pone.0234340. eCollection 2020.
The experimental quantification and modeling of the multiaxial mechanical response of polymer membranes of coronary balloon catheters have not yet been carried out. Due to the lack of insights, it is not shown whether isotropic material models can describe the material response of balloon catheter membranes expanded with nominal or higher, supra-nominal pressures. Therefore, for the first time, specimens of commercial polyamide-12 balloon catheters membranes were investigated during uniaxial and biaxial loading scenarios. Furthermore, the influence of kinematic effects on the material response was observed by comparing results from quasi-static and dynamic biaxial extension tests. Novel clamping techniques are described, which allow to test even tiny specimens taken from the balloon membranes. The results of this study reveal the semi-compliant, nonlinear, and viscoelastic character of polyamide-12 balloon catheter membranes. Above nominal pressure, the membranes show a pronounced anisotropic mechanical behavior with a stiffer response in the circumferential direction. The anisotropic feature intensifies with an increasing strain-rate. A modified polynomial model was applied to represent the realistic mechanical response of the balloon catheter membranes during dynamic biaxial extension tests. This study also includes a compact set of constitutive model parameters for the use of the proposed model in future finite element analyses to perform more accurate simulations of expanding balloon catheters.
尚未对冠状动脉球囊导管聚合物膜的多轴机械响应进行实验量化和建模。由于缺乏深入的了解，因此尚不清楚各向同性材料模型是否可以描述在名义或更高的超压下膨胀的球囊导管膜的材料响应。因此，首次在单轴和双轴加载情况下对商业聚酰胺-12 球囊导管膜的样本进行了研究。此外，通过比较准静态和动态双轴拉伸测试的结果，观察了运动学效应对材料响应的影响。本文还介绍了新颖的夹紧技术，该技术允许从小型的球囊膜样本上进行测试。本研究的结果揭示了聚酰胺-12 球囊导管膜的半柔顺、非线性和粘弹性特性。在名义压力以上，膜表现出明显的各向异性力学行为，在周向的响应更硬。各向异性特征随应变率的增加而增强。应用改进的多项式模型来表示在动态双轴拉伸测试中球囊导管膜的真实力学响应。本研究还包括一组紧凑的本构模型参数，用于在未来的有限元分析中使用所提出的模型，以更准确地模拟扩张球囊导管。
