Hodis S, Zamir M
Department of Applied Mathematics, University of Western Ontario, London, Ontario, N6A 5B7, Canada.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 Aug;78(2 Pt 1):021914. doi: 10.1103/PhysRevE.78.021914. Epub 2008 Aug 29.
Mechanical events within the thickness of the vessel wall caused by pulsatile blood flow are considered, with focus on axial dynamics of the wall, driven by the oscillatory drag force exerted by the fluid on the endothelial layer of the wall. It is shown that the focus on the axial direction makes it possible to derive simplified equations of motion which, combined with a viscoelastic model of the wall material, makes it possible in turn to obtain solutions in closed form for the displacement and stress of material elements within the wall. The viscoelastic model allows a study of the dynamics of the wall with different ratios of viscosity to elasticity of the wall material, to mimic changes in the properties of the arterial wall caused by disease or aging. It is found that when the wall is highly viscous the displacements and stresses caused by the flow are confined to a thin layer close to the inner boundary of the wall, while as the wall material becomes less viscous and more rigid the displacements and stresses spread deeper into the thickness of the wall to affect most of its elements.
考虑由脉动血流引起的血管壁厚度范围内的力学事件,重点关注血管壁的轴向动力学,这是由流体作用于血管壁内皮细胞层的振荡阻力驱动的。结果表明,关注轴向使得可以推导简化的运动方程,该方程与血管壁材料的粘弹性模型相结合,进而能够以封闭形式获得血管壁内材料元素的位移和应力的解。粘弹性模型允许研究具有不同粘度与弹性比的血管壁动力学,以模拟疾病或衰老引起的动脉壁特性变化。研究发现,当血管壁粘性很高时,由血流引起的位移和应力局限于靠近血管壁内边界的薄层,而随着血管壁材料粘性降低且刚性增加,位移和应力会深入血管壁厚度并影响其大部分元素。