论文标题
计算细胞力的应力和位移的数值方法:应用于组织的收缩
Numerical Methods to Compute Stresses and Displacements from Cellular Forces: Application to the Contraction of Tissue
论文作者
论文摘要
我们考虑了伤口收缩的数学模型,该模型基于在各向同性,同质性,胡克定律,无穷小应变理论和细胞施加的点力的假设下解决动量平衡。但是,由Dirac Delta分布描述的点力导致了一个单数溶液,在许多情况下,由于规律性较低,这可能会导致有限元方法的麻烦。因此,我们考虑了解决点力的几种替代方法,也就是说,是否处理将力作为计算域的一部分或计算域中的“孔”覆盖的区域。形式主义分别发展为沉浸的边界方法和“孔方法”。这些方法之间的一致性在理论环境中得到了验证,但也通过计算确认。但是,在迁移细胞的情况下,“孔方法”的需求更加昂贵,而且更为复杂,而它提高了数值的准确性,这使得很难适应多细胞模型。因此,对于多个细胞,我们考虑用于近似施加收缩力的细胞边界的多边形。发现低度的多边形,特别是三角形或方形的细胞边界,已经在工程精度方面可接受的结果,因此它适合计算域中大量细胞的情况。
We consider a mathematical model for wound contraction, which is based on solving a momentum balance under the assumptions of isotropy, homogeneity, Hooke's Law, infinitesimal strain theory and point forces exerted by cells. However, point forces, described by Dirac Delta distributions lead to a singular solution, which in many cases may cause trouble to finite element methods due to a low degree of regularity. Hence, we consider several alternatives to address point forces, that is, whether to treat the region covered by the cells that exert forces as part of the computational domain or as 'holes' in the computational domain. The formalisms develop into the immersed boundary approach and the 'hole approach', respectively. Consistency between these approaches is verified in a theoretical setting, but also confirmed computationally. However, the 'hole approach' is much more expensive and complicated for its need of mesh adaptation in the case of migrating cells while it increases the numerical accuracy, which makes it hard to adapt to the multi-cell model. Therefore, for multiple cells, we consider the polygon that is used to approximate the boundary of cells that exert contractile forces. It is found that a low degree of polygons, in particular triangular or square shaped cell boundaries, already give acceptable results in engineering precision, so that it is suitable for the situation with a large amount of cells in the computational domain.