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Fluid-Structure Interaction Modeling of Aneurysmal Conditions with High Blood Pressure
The Deforming-Spatial-Domain/Stabilized Space-Time (DSD/SST) formulation was introduced in [1-3] for flow problems with moving boundaries and interfaces and has been applied to a large class of problems, including FSI. In this joint work with Ryo Torii and Marie Oshima (University of Tokyo), the version of the DSD/SST formulation introduced in  is applied to computation of the FSI and wall shear stress for aneurysmal conditions with high blood pressure. This joint work is described fully in . The computations were carried out by Ryo Torii, using a computer program he wrote with guidance and help from the T*AFSM.
The computer model was extracted from the computed tomography (CT) model of the middle cerebral artery bifurcation of a 59 year-old female patient. In the FSI computation, the arterial walls are assumed to be made of a linearly elastic material, but the geometric nonlinearities are accounted for. A computation was carried out also with a model with normal blood pressure, so that we can see the influence of hypertension. The computations show that hypertension makes a significant difference in the predicted values of not only the mechanical stress in the aneurysmal wall but also the wall shear stress.
|Fig. 1. Normal and high blood pressure profiles.|
|Fig. 2. Deformation of the arterial walls at the peak systole (colors show the wall displacement in the normal direction). Left: Normal blood pressure. Right: High blood pressure. For more details, see .
|Fig. 3. Wall shear stress distribution at the peak systole. Left: Normal blood pressure. Right: High blood pressure. For wall shear stress distributions at other instants during the cardiac cycle and for flow velocities at various cross-sections, see .
1. T.E. Tezduyar, "Stabilized Finite Element Formulations for Incompressible Flow Computations", Advances in Applied Mechanics, 28 (1992) 1-44.
2. T.E. Tezduyar, M. Behr and J. Liou, "A New Strategy for Finite Element Computations Involving Moving Boundaries and Interfaces -- The Deforming-Spatial-Domain/Space-Time Procedure: I. The Concept and the Preliminary Numerical Tests", Computer Methods in Applied Mechanics and Engineering, 94 (1992) 339-351.
3. T.E. Tezduyar, M. Behr, S. Mittal and J. Liou, "A New Strategy for Finite Element Computations Involving Moving Boundaries and Interfaces -- The Deforming-Spatial-Domain/Space-Time Procedure: II. Computation of Free-surface Flows, Two-liquid Flows, and Flows with Drifting Cylinders", Computer Methods in Applied Mechanics and Engineering, 94 (1992) 353-371.
4. T.E. Tezduyar, "Computation of Moving Boundaries and Interfaces and Stabilization Parameters", International Journal for Numerical Methods in Fluids, 43 (2003) 555-575.
5. R. Torii, M. Oshima, T. Kobayashi, K. Takagi and T.E. Tezduyar, "Fluid-Structure Interaction Modeling of Aneurysmal Conditions with High and Normal Blood Pressures", Computational Mechanics, 38 (2006) 482-490.