Evaluating patient-specific abdominal aortic aneurysm wall stress based on flow-induced loading
Evaluating patient-specific abdominal aortic aneurysm wall stress based on flow-induced loading
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DOI：
10.1007/s10237-009-0163-4
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发表时间：
2010-04-01
影响因子：
3.5
通讯作者：
Peattie, R. A.
中科院分区：
文献类型：
--
作者：
Dorfmann, A.;Wilson, C.;Peattie, R. A.
在本文中，我们开发了一个生理室壁应力分析程序，将实验测量，非均匀压力加载在基于患者的有限元模拟。首先，在一系列生理相关的稳定流速下，在基于患者的管腔铸型中测量壁压分布。然后，使用已发表的等双轴应力-变形数据从动脉瘤组织样本，一个非线性超弹性本构方程被用来描述动脉瘤壁的力学行为。该模型考虑了由于几乎不可伸展的胶原纤维的快速接合而导致的特征指数硬化，并假设动脉壁的各向同性行为作为第一近似。结果表明，动脉瘤隆起后表面内表面上的局部最大主应力值为660 kPa，这是一个复杂的壁应力分布，比均匀载荷假设下的壁应力计算中通常报告的值大得多。这可能很重要，因为后壁被认为是常见的破裂部位，并且其他作者报告的动脉瘤拉伸强度与此处发现的最大应力值处于同一数量级。
In this paper, we develop a physiologic wall stress analysis procedure by incorporating experimentally measured, non-uniform pressure loading in a patient-based finite element simulation. First, the distribution of wall pressure is measured in a patient-based lumen cast at a series of physiologically relevant steady flow rates. Then, using published equi-biaxial stress-deformation data from aneurysmal tissue samples, a nonlinear hyperelastic constitutive equation is used to describe the mechanical behavior of the aneurysm wall. The model accounts of the characteristic exponential stiffening due to the rapid engagement of nearly inextensible collagen fibers and assumes, as a first approximation, an isotropic behavior of the arterial wall. The results show a complex wall stress distribution with a localized maximum principal stress value of 660 kPa on the inner surface of the posterior surface of the aneurysm bulge, a considerably larger value than has generally been reported in calculations of wall stress under the assumption of uniform loading. This is potentially significant since the posterior wall has been suggested as a common site of rupture, and the aneurysmal tensile strength reported by other authors is of the same order of magnitude as the maximum stress value found here.