Search for: homogenization-techniques
Unified model of brain tissue microstructure dynamically binds diffusion and osmosis with extracellular space geometry, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 94, Issue 3 , 2016 ; 15393755 (ISSN) ; Fotouhi, M ; Vejdani, K ; Kamali Zare, P ; Sharif University of Technology
American Physical Society 2016
We present a universal model of brain tissue microstructure that dynamically links osmosis and diffusion with geometrical parameters of brain extracellular space (ECS). Our model robustly describes and predicts the nonlinear time dependency of tortuosity (λ=D/D∗) changes with very high precision in various media with uniform and nonuniform osmolarity distribution, as demonstrated by previously published experimental data (D = free diffusion coefficient, D∗ = effective diffusion coefficient). To construct this model, we first developed a multiscale technique for computationally effective modeling of osmolarity in the brain tissue. Osmolarity differences across cell membranes lead to changes...
Modeling the interphase layer between CNT and matrix in nanocomposites using nonlinear large deformation hierarchical multiscale, Article 4th International Conference on Multiscale Materials Modeling, MMM 2008, 27 October 2008 through 31 October 2008 ; 2008 , Pages 239-242 ; 9780615247816 (ISBN) ; Naghdabadi, R ; Sharif University of Technology
Department of Scientific Computing, Florida State University 2008
We have used a hierarchical multiscale modeling scheme for the analysis of carbon nanotube reinforced nanocomposites. This scheme consists of definition of two boundary value problems, one for macroscale (the scale in which the material exists homogeneously and we are interested in modeling the material behavior on that scale), and another for microscale (the scale in which the material becomes heterogeneous and microstructural constituents emerge). The coupling between these scales is done by using homogenization techniques. Using the presented scheme, we have studied carbon nanotube (CNT) reinforced composites behavior and the effects of an interphase layer between CNT and matrix material....
Article Computer Methods in Applied Mechanics and Engineering ; Volume 376 , April , 2021 ; 00457825 (ISSN) ; Saeedmonir, S ; Sharif University of Technology
Elsevier B. V 2021
In this paper, a computational modeling tool is developed for fully coupled multiphase flow in deformable heterogeneous porous medium that consists of complex and non-uniform micro-structures using the dual continuum scales based on the computational homogenization approach. The first-order homogenization technique is employed to perform the multi-scale analysis. The governing equations of two-phase flow of immiscible fluids, including an equilibrium equation and two mass continuity equations, are considered based on the appropriate main variables. According to the well-known Hill–Mandel principle of macro-homogeneity, the proper energy types are defined instead of conventional stress power...
Nonlinear mechanics of soft composites: hyperelastic characterization of white matter tissue components, Article Biomechanics and Modeling in Mechanobiology ; Volume 19, Issue 3 , 2020 , Pages 1143-1153 ; Shamloo, A ; Farahmand, F ; Sharif University of Technology
This paper presents a bi-directional closed-form analytical solution, in the framework of nonlinear soft composites mechanics, for top-down hyperelastic characterization of brain white matter tissue components, based on the directional homogenized responses of the tissue in the axial and transverse directions. The white matter is considered as a transversely isotropic neo-Hookean composite made of unidirectional distribution of axonal fibers within the extracellular matrix. First, two homogenization formulations are derived for the homogenized axial and transverse shear moduli of the tissue, based on definition of the strain energy density function. Next, the rule of mixtures and...
Nonlinear hierarchical multiscale modeling of cortical bone considering its nanoscale microstructure, Article Journal of Biomechanics ; Volume 42, Issue 10 , 2009 , Pages 1560-1565 ; 00219290 (ISSN) ; Naghdabadi, R ; Sharif University of Technology
We have used a hierarchical multiscale modeling scheme for the analysis of cortical bone considering it as a nanocomposite. This scheme consists of definition of two boundary value problems, one for macroscale, and another for microscale. The coupling between these scales is done by using the homogenization technique. At every material point in which the constitutive model is needed, a microscale boundary value problem is defined using a macroscopic kinematical quantity and solved. Using the described scheme, we have studied elastic properties of cortical bone considering its nanoscale microstructural constituents with various mineral volume fractions. Since the microstructure of bone...