The Experts below are selected from a list of 714 Experts worldwide ranked by ideXlab platform

Zilian Andreas - One of the best experts on this subject based on the ideXlab platform.

  • ANN-aided incremental multiscale-remodelling-based finite Strain poroelasticity
    2021
    Co-Authors: Dehghani Hamidreza, Zilian Andreas
    Abstract:

    Mechanical modelling of poroelastic media under finite Strain is usually carried out via phenomenological models neglecting complex micro-macro scales interdependency. One reason is that the mathematical two-scale analysis is only straightforward assuming Infinitesimal Strain Theory. Exploiting the potential of ANNs for fast and reliable upscaling and localisation procedures, we propose an incremental numerical approach that considers rearrangement of the cell properties based on its current deformation, which leads to the remodelling of the macroscopic model after each time increment. This computational framework is valid for finite Strain and large deformation problems while it ensures Infinitesimal Strain increments within time steps. The full effects of the interdependency between the properties and response of macro and micro scales are considered for the first time providing more accurate predictive analysis of fluid-saturated porous media which is studied via a numerical consolidation example. Furthermore, the (nonlinear) deviation from Darcy's law is captured in fluid filtration numerical analyses. Finally, the brain tissue mechanical response under uniaxial cyclic test is simulated and studied

  • ANN-aided incremental multiscale-remodelling-based finite Strain poroelasticity
    'Springer Science and Business Media LLC', 2021
    Co-Authors: Dehghani Hamidreza, Zilian Andreas
    Abstract:

    Mechanical modelling of poroelastic media under finite Strain is usually carried out via phenomenological models neglecting complex micro-macro scales interdependency. One reason is that the mathematical two-scale analysis is only straightforward assuming Infinitesimal Strain Theory. Exploiting the potential of ANNs for fast and reliable upscaling and localisation procedures, we propose an incremental numerical approach that considers rearrangement of the cell properties based on its current deformation, which leads to the remodelling of the macroscopic model after each time increment. This computational framework is valid for finite Strain and large deformation problems while it ensures Infinitesimal Strain increments within time steps. The full effects of the interdependency between the properties and response of macro and micro scales are considered for the first time providing a more accurate predictive analysis of fluid-saturated porous media which is studied via a numerical consolidation example. Furthermore, the (nonlinear) deviation from Darcy’s law is captured in fluid filtration numerical analyses. Finally, the brain tissue mechanical response under the uniaxial cyclic test is simulated and studied

Reza Behrou - One of the best experts on this subject based on the ideXlab platform.

  • numerical study of temperature effects on the poro viscoelastic behavior of articular cartilage
    Journal of The Mechanical Behavior of Biomedical Materials, 2018
    Co-Authors: Reza Behrou, Hamid Foroughi, Fardad Haghpanah
    Abstract:

    This paper presents a new approach to study the effects of temperature on the poro- elastic and viscoelastic behavior of articular cartilage. Biphasic solid-fluid mixture Theory is applied to study the poro-mechanical behavior of articular cartilage in a fully saturated state. The balance of linear momentum, mass, and energy are considered to describe deformation of the solid skeleton, pore fluid pressure, and temperature distribution in the mixture. The mechanical model assumes both linear elastic and viscoelastic isotropic materials, Infinitesimal Strain Theory, and a time-dependent response. The influence of temperature on the mixture behavior is modeled through temperature dependent mass density and volumetric thermal Strain. The fluid flow through the porous medium is described by the Darcy's law. The stress-Strain relation for time-dependent viscoelastic deformation in the solid skeleton is described using the generalized Maxwell model. A verification example is presented to illustrate accuracy and efficiency of the developed finite element model. The influence of temperature is studied through examining the behavior of articular cartilage for confined and unconfined boundary conditions. Furthermore, articular cartilage under partial loading condition is modeled to investigate the deformation, pore fluid pressure, and temperature dissipation processes. The results suggest significant impacts of temperature on both poro- elastic and viscoelastic behavior of articular cartilage.

  • level set topology optimization of structural problems with interface cohesion
    International Journal for Numerical Methods in Engineering, 2017
    Co-Authors: Reza Behrou, Matthew Lawry, Kurt Maute
    Abstract:

    Summary This paper presents a finite element topology optimization framework for the design of two-phase structural systems considering contact and cohesion phenomena along the interface. The geometry of the material interface is described by an explicit level set method, and the structural response is predicted by the extended finite element method. In this work, the interface condition is described by a bilinear cohesive zone model on the basis of the traction-separation constitutive relation. The non-penetration condition in the presence of compressive interface forces is enforced by a stabilized Lagrange multiplier method. The mechanical model assumes a linear elastic isotropic material, Infinitesimal Strain Theory, and a quasi-static response. The optimization problem is solved by a nonlinear programming method, and the design sensitivities are computed by the adjoint method. The performance of the presented method is evaluated by 2D and 3D numerical examples. The results obtained from topology optimization reveal distinct design characteristics for the various interface phenomena considered. In addition, 3D examples demonstrate optimal geometries that cannot be fully captured by reduced dimensionality. The optimization framework presented is limited to two-phase structural systems where the material interface is coincident in the undeformed configuration, and to structural responses that remain valid considering small Strain kinematics. Copyright © 2017 John Wiley & Sons, Ltd.

Fardad Haghpanah - One of the best experts on this subject based on the ideXlab platform.

  • numerical study of temperature effects on the poro viscoelastic behavior of articular cartilage
    Journal of The Mechanical Behavior of Biomedical Materials, 2018
    Co-Authors: Reza Behrou, Hamid Foroughi, Fardad Haghpanah
    Abstract:

    This paper presents a new approach to study the effects of temperature on the poro- elastic and viscoelastic behavior of articular cartilage. Biphasic solid-fluid mixture Theory is applied to study the poro-mechanical behavior of articular cartilage in a fully saturated state. The balance of linear momentum, mass, and energy are considered to describe deformation of the solid skeleton, pore fluid pressure, and temperature distribution in the mixture. The mechanical model assumes both linear elastic and viscoelastic isotropic materials, Infinitesimal Strain Theory, and a time-dependent response. The influence of temperature on the mixture behavior is modeled through temperature dependent mass density and volumetric thermal Strain. The fluid flow through the porous medium is described by the Darcy's law. The stress-Strain relation for time-dependent viscoelastic deformation in the solid skeleton is described using the generalized Maxwell model. A verification example is presented to illustrate accuracy and efficiency of the developed finite element model. The influence of temperature is studied through examining the behavior of articular cartilage for confined and unconfined boundary conditions. Furthermore, articular cartilage under partial loading condition is modeled to investigate the deformation, pore fluid pressure, and temperature dissipation processes. The results suggest significant impacts of temperature on both poro- elastic and viscoelastic behavior of articular cartilage.

Dehghani Hamidreza - One of the best experts on this subject based on the ideXlab platform.

  • ANN-aided incremental multiscale-remodelling-based finite Strain poroelasticity
    2021
    Co-Authors: Dehghani Hamidreza, Zilian Andreas
    Abstract:

    Mechanical modelling of poroelastic media under finite Strain is usually carried out via phenomenological models neglecting complex micro-macro scales interdependency. One reason is that the mathematical two-scale analysis is only straightforward assuming Infinitesimal Strain Theory. Exploiting the potential of ANNs for fast and reliable upscaling and localisation procedures, we propose an incremental numerical approach that considers rearrangement of the cell properties based on its current deformation, which leads to the remodelling of the macroscopic model after each time increment. This computational framework is valid for finite Strain and large deformation problems while it ensures Infinitesimal Strain increments within time steps. The full effects of the interdependency between the properties and response of macro and micro scales are considered for the first time providing more accurate predictive analysis of fluid-saturated porous media which is studied via a numerical consolidation example. Furthermore, the (nonlinear) deviation from Darcy's law is captured in fluid filtration numerical analyses. Finally, the brain tissue mechanical response under uniaxial cyclic test is simulated and studied

  • ANN-aided incremental multiscale-remodelling-based finite Strain poroelasticity
    'Springer Science and Business Media LLC', 2021
    Co-Authors: Dehghani Hamidreza, Zilian Andreas
    Abstract:

    Mechanical modelling of poroelastic media under finite Strain is usually carried out via phenomenological models neglecting complex micro-macro scales interdependency. One reason is that the mathematical two-scale analysis is only straightforward assuming Infinitesimal Strain Theory. Exploiting the potential of ANNs for fast and reliable upscaling and localisation procedures, we propose an incremental numerical approach that considers rearrangement of the cell properties based on its current deformation, which leads to the remodelling of the macroscopic model after each time increment. This computational framework is valid for finite Strain and large deformation problems while it ensures Infinitesimal Strain increments within time steps. The full effects of the interdependency between the properties and response of macro and micro scales are considered for the first time providing a more accurate predictive analysis of fluid-saturated porous media which is studied via a numerical consolidation example. Furthermore, the (nonlinear) deviation from Darcy’s law is captured in fluid filtration numerical analyses. Finally, the brain tissue mechanical response under the uniaxial cyclic test is simulated and studied

Maarten Fauvart - One of the best experts on this subject based on the ideXlab platform.

  • model driven controlled alteration of nanopillar cap architecture reveals its effects on bactericidal activity
    Microorganisms, 2020
    Co-Authors: Taiyeb Zahir, Jiri Pesek, S Franke, Jasper Van Pee, Ashish Rathore, Bart Smeets, Herman Ramon, Maarten Fauvart
    Abstract:

    Nanostructured surfaces can be engineered to kill bacteria in a contact-dependent manner. The study of bacterial interactions with a nanoscale topology is thus crucial to developing antibacterial surfaces. Here, a systematic study of the effects of nanoscale topology on bactericidal activity is presented. We describe the antibacterial properties of highly ordered and uniformly arrayed cotton swab-shaped (or mushroom-shaped) nanopillars. These nanostructured surfaces show bactericidal activity against Staphylococcus aureus and Pseudomonas aeruginosa. A biophysical model of the cell envelope in contact with the surface, developed ab initio from the Infinitesimal Strain Theory, suggests that bacterial adhesion and subsequent lysis are highly influenced by the bending rigidity of the cell envelope and the surface topography formed by the nanopillars. We used the biophysical model to analyse the influence of the nanopillar cap geometry on the bactericidal activity and made several geometrical alterations of the nanostructured surface. Measurement of the bactericidal activities of these surfaces confirms model predictions, highlights the non-trivial role of cell envelope bending rigidity, and sheds light on the effects of nanopillar cap architecture on the interactions with the bacterial envelope. More importantly, our results show that the surface nanotopology can be rationally designed to enhance the bactericidal efficiency.