Li J, Luo X Y, Kuang Z B
School of Civil Engineering and Mechanics, Xi'an Jiaotong University, 710049 Xi'an, People's Republic of China.
J Biomech. 2001 Oct;34(10):1279-89. doi: 10.1016/s0021-9290(01)00092-6.
The anisotropic property of porcine aortic valve leaflet has potentially significant effects on its mechanical behaviour and the failure mechanisms. However, due to its complex nature, testing and modelling the anisotropic porcine aortic valves remains a continuing challenge to date. This study has developed a nonlinear anisotropic finite element model for porcine heart valves. The model is based on the uniaxial experimental data of porcine aortic heart valve leaflet and the properties of nonlinear composite material. A finite element code is developed to solve this problem using the 8-node super-parameter nonlinear shells and the update Lagrangian method. The stress distribution and deformation of the porcine aortic valves with either uniform and non-uniform thicknesses in closed phase and loaded condition are calculated. The results showed significant changes in the stress distributions due to the anisotropic property of the leaflets. Compared with the isotropic valve at the same loading condition, it is found that the site of the peak stress of the anisotropic leaflet is different; the maximum longitudinal normal stress is increased, but the maximum transversal normal stress and in-plane shear stress are reduced. We conclude that it is very important to consider the anisotropic property of the porcine heart valves in order to understand the failure mechanism of such valves in vivo.
猪主动脉瓣叶的各向异性特性对其力学行为和失效机制可能具有重大影响。然而，由于其性质复杂，迄今为止，对各向异性猪主动脉瓣进行测试和建模仍然是一项持续的挑战。本研究建立了猪心脏瓣膜的非线性各向异性有限元模型。该模型基于猪主动脉心脏瓣膜叶的单轴实验数据和非线性复合材料的特性。开发了一个有限元代码，使用8节点超参数非线性壳和更新拉格朗日方法来解决此问题。计算了在关闭阶段和加载条件下具有均匀和非均匀厚度的猪主动脉瓣的应力分布和变形。结果表明，由于瓣叶的各向异性特性，应力分布发生了显著变化。与相同加载条件下的各向同性瓣膜相比，发现各向异性瓣叶的峰值应力位置不同；最大纵向正应力增加，但最大横向正应力和面内剪应力减小。我们得出结论，考虑猪心脏瓣膜的各向异性特性对于理解此类瓣膜在体内的失效机制非常重要。
