Bathe M, Kamm R D
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge 02139, USA.
J Biomech Eng. 1999 Aug;121(4):361-9. doi: 10.1115/1.2798332.
A new model is used to analyze the fully coupled problem of pulsatile blood flow through a compliant, axisymmetric stenotic artery using the finite element method. The model uses large displacement and large strain theory for the solid, and the full Navier-Stokes equations for the fluid. The effect of increasing area reduction on fluid dynamic and structural stresses is presented. Results show that pressure drop, peak wall shear stress, and maximum principal stress in the lesion all increase dramatically as the area reduction in the stenosis is increased from 51 to 89 percent. Further reductions in stenosis cross-sectional area, however, produce relatively little additional change in these parameters due to a concomitant reduction in flow rate caused by the losses in the constriction. Inner wall hoop stretch amplitude just distal to the stenosis also increases with increasing stenosis severity, as downstream pressures are reduced to a physiological minimum. The contraction of the artery distal to the stenosis generates a significant compressive stress on the downstream shoulder of the lesion. Dynamic narrowing of the stenosis is also seen, further augmenting area constriction at times of peak flow. Pressure drop results are found to compare well to an experimentally based theoretical curve, despite the assumption of laminar flow.
一种新模型被用于通过有限元法分析脉动血流通过顺应性轴对称狭窄动脉的全耦合问题。该模型对固体采用大位移和大应变理论，对流体采用完整的纳维 - 斯托克斯方程。给出了面积缩减增加对流体动力学和结构应力的影响。结果表明，随着狭窄处面积缩减从51%增加到89%，病变处的压降、峰值壁面剪应力和最大主应力均显著增加。然而，由于狭窄处流量因收缩处的损失而随之减少，狭窄横截面面积的进一步减小在这些参数上产生的额外变化相对较小。随着下游压力降至生理最小值，狭窄远端的内壁环向拉伸幅度也随着狭窄严重程度的增加而增大。狭窄远端动脉的收缩在病变的下游肩部产生显著的压应力。还观察到狭窄的动态变窄，在峰值血流时进一步增大了面积收缩。尽管假设为层流，但压降结果与基于实验的理论曲线比较吻合。
