Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Dynamics, Immerwahrstraße 1, 91058 Erlangen, Germany.
Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Applied Dynamics, Immerwahrstraße 1, 91058 Erlangen, Germany.
J Biomech. 2021 Jan 22;115:110153. doi: 10.1016/j.jbiomech.2020.110153. Epub 2020 Dec 15.
In the last decades, various computational models have been developed to simulate cardiac electromechanics. The most common numerical tool is the finite element method (FEM). However, this method crucially depends on the mesh quality. For complex geometries such as cardiac structures, it is convenient to use tetrahedral discretisations which can be generated automatically. On the other hand, such automatic meshing with tetrahedrons together with large deformations often lead to elements distortion and volumetric locking. To overcome these difficulties, different smoothed finite element methods (S-FEMs) have been proposed in the recent years. They are known to be volumetric locking free, less sensitive to mesh distortion and so far have been used e.g. in simulation of passive cardiac mechanics. In this work, we extend for the first time node-based S-FEM (NS-FEM) towards active cardiac mechanics. Firstly, the sensitivity to mesh distortion is tested and compared to that of FEM. Secondly, an active contraction in circumferentially aligned fibre direction is modelled in the healthy and the infarcted case. We show, that the proposed method is more robust with respect to mesh distortion and computationally more efficient than standard FEM. Being furthermore free of volumetric locking problems makes S-FEM a promising alternative in modelling of active cardiac mechanics, respectively electromechanics.
在过去的几十年中，已经开发出了各种计算模型来模拟心脏机电。最常用的数值工具是有限元法（FEM）。然而，这种方法严重依赖于网格质量。对于心脏结构等复杂几何形状，使用可以自动生成的四面体离散化是方便的。另一方面，这种带有大变形的四面体自动网格通常会导致元素变形和体积锁定。为了克服这些困难，近年来提出了不同的平滑有限元方法（S-FEM）。它们已知是无体积锁定的，对网格变形的敏感性较小，并且迄今为止已被用于例如被动心脏力学的模拟。在这项工作中，我们首次将基于节点的 S-FEM（NS-FEM）扩展到主动心脏力学。首先，测试了对网格变形的敏感性，并与 FEM 进行了比较。其次，在健康和梗塞的情况下，模拟了沿周向对齐的纤维方向的主动收缩。我们表明，与标准 FEM 相比，所提出的方法对网格变形更稳健，并且在计算上更有效。由于不存在体积锁定问题，因此 S-FEM 是主动心脏力学或机电模拟的有前途的替代方法。
