BACKGROUND Previous studies on aneurysm modeling have focused on the blood rheology and vessel elasticity separately. The combined effects of blood shear thinning properties and wall elasticity need to be revealed. OBJECTIVE To provide insights on how pulsatile hemodynamics vary with blood rheology and vessel elasticity for a developed abdominal aortic aneurysm (AAA). METHOD An Arbitrary Lagrangian-Eulerian fluid-solid interaction method is adopted with the Newtonian and the shear thinning Carreau constitutive models for the fluid with the linearly elastic and the hyperelastic Yeoh models for the vessel. Finite element based numerical solver is used to simulate the blood flow in the AAA. RESULTS Newtonian model overestimates the velocity values compared to the Carreau model and the difference in the velocity field increases as the shear rate decreases at the instances of the cardiac cycle. The rigid walled simulations display higher deviations in the velocity and wall shear stress with the fluid rheology. The risk indicators show that Newtonian assumption combined with the linearly elastic model may overlook degeneration risk of arterial tissue. CONCLUSIONS Newtonian assumption for the blood as well as modelling the arterial wall as linearly elastic lead to significant differences in oscillatory hemodynamic properties with respect to the use of Carreau fluid together with hyperelastic vessel model, even in large vessel aneurysms.

中文翻译：

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血液流变学和壁弹性在脉动血流条件下对腹主动脉瘤的影响的数值研究。

背景技术先前关于动脉瘤建模的研究分别集中于血液流变学和血管弹性。需要揭示血液剪切稀化特性和壁弹性的综合作用。目的探讨腹部主动脉瘤（AAA）的搏动性血流动力学随血液流变学和血管弹性的变化。方法采用任意拉格朗日-欧拉流固耦合方法，对流体采用牛顿和剪切稀化Carreau本构模型，对容器采用线性弹性和超弹性Yeoh模型。基于有限元的数值求解器用于模拟AAA中的血流。结果与Carreau模型相比，牛顿模型高估了速度值，并且在心动周期时，随着剪切速率的降低，速度场中的差异增加。刚性壁仿真显示出随着流体流变性的速度和壁切应力的更大偏差。风险指标表明，牛顿假设与线性弹性模型相结合可能会忽略动脉组织退化的风险。结论牛顿关于血液的假设以及将动脉壁建模为线性弹性，导致相对于Carreau流体和超弹性血管模型的使用，即使在大血管动脉瘤中，振荡血液动力学特性也存在显着差异。刚性壁仿真显示出随着流体流变性的速度和壁切应力的更大偏差。风险指标表明，牛顿假设与线性弹性模型相结合可能会忽略动脉组织退化的风险。结论牛顿关于血液的假设以及将动脉壁建模为线性弹性，导致相对于Carreau流体和超弹性血管模型的使用，即使在大血管动脉瘤中，振荡血液动力学特性也存在显着差异。刚性壁仿真显示出随着流体流变性的速度和壁切应力的更大偏差。风险指标表明，牛顿假设与线性弹性模型相结合可能会忽略动脉组织退化的风险。结论牛顿关于血液的假设以及将动脉壁建模为线性弹性，导致相对于Carreau流体和超弹性血管模型的使用，即使在大血管动脉瘤中，振荡血液动力学特性也存在显着差异。