Department of Biomedical Engineering, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA.
J Theor Biol. 2011 Oct 7;286(1):92-9. doi: 10.1016/j.jtbi.2011.05.037. Epub 2011 Jun 15.
Recently, a novel linearized constitutive model with a new strain measure that absorbs the material nonlinearity was validated for arteries. In this study, the linearized arterial stress-strain relationship is implemented into a finite element method package, ANSYS, via the user subroutine USERMAT. The reference configuration is chosen to be the closed cylindrical tube (no-load state) rather than the open sector (zero-stress state). The residual strain is taken into account by analytic calculation and the incompressibility condition is enforced with Lagrange penalty method. Axisymmetric finite element analyses are conducted to demonstrate potential applications of this approach in a complex boundary value problem where angioplasty balloon interacts with the vessel wall. The model predictions of transmural circumferential and compressive radial stress distributions were also validated against an exponential-type Fung model, and the mean error was found to be within 6%.
最近，一种新的线性化本构模型被验证可用于动脉，该模型具有一种新的应变度量，可以吸收材料的非线性。在这项研究中，线性化的动脉应力-应变关系通过用户子程序 USERMAT 被实现到有限元方法包 ANSYS 中。参考构形被选择为封闭的圆柱管（无负载状态）而不是开扇区（零应力状态）。残余应变通过解析计算考虑，并且不可压缩性条件通过拉格朗日罚函数方法强制满足。轴对称有限元分析被进行，以展示这种方法在一个复杂的边界值问题中的潜在应用，其中血管成形球囊与血管壁相互作用。模型预测的壁内周向和压缩径向应力分布也与指数型 Fung 模型进行了验证，平均误差被发现处于 6%以内。
