Schmid P, Stuber M, Boesiger P, Hess O M, Niederer P
Institute of Biomed. Engineering and Med. Informatics, Uni and ETH Zurich, Switzerland.
Technol Health Care. 1995 Dec;3(3):209-14.
The determination of characteristic cardiac parameters, such as displacement, stress and strain distribution are essential for an understanding of the mechanics of the heart. The calculation of these parameters has been limited until recently by the use of idealised mathematical representations of biventricular geometries and by applying simple material laws. On the basis of 20 short axis heart slices and in consideration of linear and nonlinear material behaviour we have developed a FE model with about 100,000 degrees of freedom. Marching Cubes and Phong's incremental shading technique were used to visualise the three dimensional geometry. In a quasistatic FE analysis continuous distribution of regional stress and strain corresponding to the endsystolic state were calculated. Substantial regional variation of the Von Mises stress and the total strain energy were observed at all levels of the heart model. The results of both the linear elastic model and the model with a nonlinear material description (Mooney-Rivlin) were compared. While the stress distribution and peak stress values were found to be comparable, the displacement vectors obtained with the nonlinear model were generally higher in comparison with the linear elastic case indicating the need to include nonlinear effects.
确定诸如位移、应力和应变分布等特征心脏参数对于理解心脏力学至关重要。直到最近，这些参数的计算还受到双心室几何形状理想化数学表示的使用以及应用简单材料定律的限制。基于20个短轴心脏切片，并考虑线性和非线性材料行为，我们开发了一个具有约100,000个自由度的有限元模型。使用移动立方体和Phong增量着色技术来可视化三维几何形状。在准静态有限元分析中，计算了对应于收缩末期状态的区域应力和应变的连续分布。在心脏模型的所有层面都观察到了冯·米塞斯应力和总应变能的显著区域变化。比较了线性弹性模型和具有非线性材料描述（穆尼-里夫林）模型的结果。虽然发现应力分布和峰值应力值具有可比性，但与线性弹性情况相比，非线性模型获得的位移矢量通常更高，这表明需要考虑非线性效应。
