Efficient anisotropic adaptive discretization of the cardiovascular system

Sahni, Onkar; Müller, Jens; Jansen, Kenneth E.; Shephard, Mark S.; Taylor, Charles A.

doi:10.1016/j.cma.2005.10.018

Cited by 153 publications

(121 citation statements)

References 30 publications

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“…A CFD analysis was performed to simulate blood flow and pressure in the endograft using techniques developed in-house that enabled accurate representation of the TAA geometry and of the postoperative hemodynamic variables (i.e., cardiac output, heart rate, and systolic and diastolic blood pressure). [8][9][10][11][12][13] Once the CFD analysis was completed, the magnitude and direction of the time-varying displacement forces (DF) acting on each of the 4 modules (i.e., DF 1 , DF 2 , DF 3 , DF 4 ; see Fig. 2) of the endograft were calculated.…”

Section: Model Designmentioning

confidence: 99%

Computational Analysis of Stresses Acting on Intermodular Junctions in Thoracic Aortic Endografts

Prasad

Gorrepati

et al. 2011

Journal of Endovascular Therapy

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¤ ¤Purpose: To evaluate the biomechanical and hemodynamic forces acting on the intermodular junctions of a multi-component thoracic endograft and elucidate their influence on the development of type III endoleak due to disconnection of stent-graft segments.Methods: Three-dimensional computer models of the thoracic aorta and a 4-component thoracic endograft were constructed using postoperative (baseline) and follow-up computed tomography (CT) data from a 69-year-old patient who developed type III endoleak 4 years after stent-graft placement. Computational fluid dynamics (CFD) techniques were used to quantitate the displacement forces acting on the device. The contact stresses between the different modules of the graft were then quantified using computational solid mechanics (CSM) techniques. Lastly, the intermodular junction frictional stability was evaluated using a Coulomb model. Results:The CFD analysis revealed that curvature and length are key determinants of the displacement forces experienced by each endograft and that the first 2 modules were exposed to displacement forces acting in opposite directions in both the lateral and longitudinal axes. The CSM analysis revealed that the highest concentration of stresses occurred at the junction between the first and second modules of the device. Furthermore, the frictional analysis demonstrated that most of the surface area (53%) of this junction had unstable contact. The predicted critical zone of intermodular stress concentration and frictional instability matched the location of the type III endoleak observed in the 4-year follow-up CT image. Conclusion:The region of larger intermodular stresses and highest frictional instability correlated with the zone where a type III endoleak developed 4 years after thoracic stentgraft placement. Computational techniques can be helpful in evaluating the risk of endograft migration and potential for modular disconnection and may be useful in improving device placement strategies and endograft design.

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Section: Model Designmentioning

confidence: 99%

Computational Analysis of Stresses Acting on Intermodular Junctions in Thoracic Aortic Endografts

Prasad

Gorrepati

et al. 2011

Journal of Endovascular Therapy

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“…Since mesh metric field represents the transformation that maps an ellipsoid into a unit sphere, any tetrahedron that satisfies the mesh metric field in the unstructured part of the mesh should be a unit equilateral tetrahedron in the transformed space [1] (see left of Figure 2). Meanwhile, in order to align mesh metric decomposition with the boundary layer structure specification, at any vertex of a boundary layer the ellipsoid associated with the metric tensor is decomposed into a planar part, which dictates in-plane size resolution control, and a normal component which influences the the stack height adjustment [11,12]. Figure 2 (right) illustrates the decomposition of mesh metric field for the boundary layer vertices.…”

Section: Mesh Metric Fieldmentioning

confidence: 99%

“…It is a parallelization of mesh adaptation technique previously presented and proved the robustness of the method with the analysis of simulation results [11,12]. The advantage of this method is the ability to handle curved complex 3D geometries while being able to achieve a desired degree of anisotropy with inexpensive solution transfer process.…”

Section: Introductionmentioning

confidence: 99%

“…In these regions carefully constructed boundary layers that consider the physics of the flow and the abilities of the flow models used result in the most effective means to construct the local portions of the mesh [11][12][13][14]. The best method of construction of such boundary layer meshes is to decompose the mesh in an unstructured mesh in the "plane of the surface" and a graded and structured mesh in the normal direction [11,12,[15][16][17]. Layered structure of elements in boundary layer meshes near no-slip walls plays a critical role.…”

Section: Introductionmentioning

confidence: 99%

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Parallel Adaptive Boundary Layer Meshing for CFD Analysis

Ovcharenko

Chitale

Sahni

et al. 2013

Proceedings of the 21st International Meshing Roundtable

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Summary. This paper describes a parallel procedure for anisotropic mesh adaptation with boundary layers for use in scalable CFD simulations. The parallel mesh adaptation algorithm operates with local mesh modification operations developed for both unstructured and boundary layer parts of the mesh. The adaptive approach maintains layered elements near the viscous walls and accounts for the mesh modification operations that are carried out in parallel on a distributed mesh. In the process mesh relationships and approximations with respect to curved complex 3D geometries of interest are properly maintained. The parallel mesh adaptation procedures are applied to two problems: a heat transfer manifold and a scramjet engine.

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“…In addition to the CFD flow solver PHASTA, adaptive meshing [8,9,11,10] and mesh partitioning [7] techniques are other essential ingredients required to generate and partition significantly large (in the order of 5 billion or more elements) 3D unstructured finite element meshes for the target applications. Indeed, the application of reliable numerical simulations requires them to be executed in an automated manner with explicit control of the approximations made.…”

Section: Adaptive Mesh Control and Mesh Partitioningmentioning

confidence: 99%

Efficient anisotropic adaptive discretization of the cardiovascular system

Cited by 153 publications

References 30 publications

Computational Analysis of Stresses Acting on Intermodular Junctions in Thoracic Aortic Endografts

Computational Analysis of Stresses Acting on Intermodular Junctions in Thoracic Aortic Endografts

Parallel Adaptive Boundary Layer Meshing for CFD Analysis

Petascale, Adaptive CFD (ALCF ESP Technical Report): ALCF-2 Early Science Program Technical Report

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