EVENTO
Integrative Computational Modeling in Hemodynamics: from Preload Analysis to 3D-1D Simulations
Tipo de evento: Seminário de Avaliação - Série A
In this seminar a comprehensive approach for the simulation of arterial blood flow and its effect on the stress state of the arterial wall is presented. An original modeling framework is proposed for the treatment of hemodynamic problems with increased realism, featuring an unprecedented combination of several modeling techniques in order to account for i) the fact that the initial (image-based) geometry corresponds to a configuration which is at equilibrium with an internal pressure and with the existing tethering forces located at the artificial boundaries delimiting the region of interest; ii) the fluid-structure interaction (FSI) problem; iii) the complex constitutive behavior of the arterial wall; iv) the influence of surrounding tissues; and v) the interaction of the vessel with the rest of the cardiovascular system.In order to tackle the issues described above, the preload mechanical problem is solved in a first stage, finding thus the zero-load material configuration which is employed to define suitable constitutive equations. This is performed by finding the solution for the mechanical equilibrium of the given image configuration considering the vessel at this state to be loaded by an internal reference (diastolic) pressure and an axial traction (caused by tethering forces) at the artificial boundaries. It is worthwhile to mention that this axial traction is such that a previously defined pre-stretch level is presented on the equilibrium image configuration.Once the reference configuration is obtained, a complete 3D FSI simulation is carried out, coupled with a dimensionally reduced 1D model of the rest of the cardiovascular system. Strong coupling via fixed-point iterations is achieved for the FSI, while the dimensionally heterogeneous coupling is achieved through a Broyden method. Regarding the constitutive modeling, a fiber-reinforced hyperelastic law is considered; collagen orientation is defined on the image based geometry and its reference length is set on this image (diastolic) configuration.The capabilities of this integrative approach will be demonstrated through an example of a patient-specific geometry featuring a cerebral aneurysm, displaying a 3D-1D FSI simulation with mechanical preload. Furthermore, the sensitivity with respect to the existence of the preload stresses is assessed to quantify the importance of this issue.
Data Início: 03/11/2015 Hora: 10:00 Data Fim: 03/11/2015 Hora: 14:00
Local: LNCC - Laboratório Nacional de Computação Ciêntifica - Auditorio A
Aluno: Gonzalo Damián Ares - LABORATÓRIO NACIONAL DE COMPUTAÇÃO CIENTÍFICA - LNCC
Orientador: Pablo Javier Blanco - Laboratório Nacional de Computação Científica - LNCC
Participante Banca Examinadora: Abimael Fernando Dourado Loula - Laboratório Nacional de Computação Científica - LNCC Alessandro Veneziani - Department of Mathematics and Computer Science and Wallace H. Coulter Department of Biomedical Engineering, Emory University, USA - Antônio André Novotny - LNCC - LNCC Pablo Javier Blanco - Laboratório Nacional de Computação Científica - LNCC
