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Vasculogenesis and angiogenesis are two different mechanisms for blood vessel formation. Angiogenesis occurs when new vessels sprout from pre-existing vasculature in response to external chemical stimuli. Vasculogenesis occurs via the reorganization of randomly distributed cells into a blood vessel network. Experimental models of vasculogenesis have suggested that the cells exert traction forces onto the extracellular matrix and that these forces may play an important role in the network forming...
Vasculogenesis and angiogenesis are two different mechanisms for blood
vessel formation. Angiogenesis occurs when new vessels sprout from
pre-existing vasculature in response to external chemical stimuli.
Vasculogenesis occurs via the reorganization of randomly distributed
cells into a blood vessel network. Experimental models
of vasculogenesis have suggested that the cells exert traction forces
onto the extracellular matrix and that these forces may play
an important role in the network forming...
We propose a quasi-Newton algorithm for solving fluid-structure interaction problems. The basic idea of the method is to build an approximate tangent operator which is cost effective and which takes into account the so-called added mass effect. Various test cases show that the method allows a significant reduction of the computational effort compared to relaxed fixed point algorithms. We present 2D and 3D fluid-structure simulations performed either with a simple 1D structure model or with shells...
We propose a quasi-Newton algorithm for solving
fluid-structure interaction problems. The basic idea of the method is
to build an approximate tangent operator which is cost effective and
which takes into account the so-called added mass effect.
Various test cases show that the method allows a significant reduction
of the computational effort compared to relaxed fixed point
algorithms. We present 2D and 3D fluid-structure simulations performed
either with a simple 1D structure model or with...
A hyperelastic constitutive law, for use in anatomically accurate finite element models of living structures, is suggested for the passive and the active mechanical properties of incompressible biological tissues. This law considers the passive and active states as a same hyperelastic continuum medium, and uses an activation function in order to describe the whole contraction phase. The variational and the FE formulations are also presented, and the FE code has been validated and applied to describe...
A hyperelastic constitutive law, for use in anatomically accurate finite element models of
living structures, is suggested for the passive and the active mechanical properties of incompressible
biological tissues. This law considers the passive and active states as a same hyperelastic continuum
medium, and uses an activation function in order to describe the whole contraction phase.
The variational and the FE formulations are also presented, and the FE code has been validated
and applied to describe...
In this paper we elaborate a model to describe some aspects of the human lung considered as a continuous, deformable, medium.
To that purpose, we
study the asymptotic behavior of a
spring-mass system with dissipation. The key feature of our approach is the nature of this dissipation phenomena, which is related here to the flow of a viscous fluid through a dyadic tree of pipes (the branches), each exit of which being connected to an air pocket (alvelola) delimited by two successive masses.
The...
Mathematics Subject Classification: 26A33, 74B20, 74D10, 74L15The popular elastic law of Fung that describes the non-linear stress-
strain behavior of soft biological tissues is extended into a viscoelastic material
model that incorporates fractional derivatives in the sense of Caputo. This one-dimensional material model is then transformed into a
three-dimensional constitutive model that is suitable for general analysis.
The model is derived in a configuration that differs from the current, or
spatial,...
We derive a constitutive law for the myocardium from the description of both the geometrical arrangement of cardiomyocytes and their individual mechanical behaviour. We model a set of cardiomyocytes by a quasiperiodic discrete lattice of elastic bars interacting by means of moments. We work in a large displacement framework and we use a discrete homogenization technique. The macroscopic constitutive law is obtained through the resolution of a nonlinear self-equilibrum system of the discrete lattice...
We derive a constitutive law for the myocardium from the description of both the geometrical arrangement of
cardiomyocytes and their individual mechanical behaviour. We model a set of cardiomyocytes by a quasiperiodic discrete
lattice of elastic bars interacting by means of moments. We work in a large displacement framework and we use a discrete
homogenization technique. The macroscopic constitutive law is obtained through the resolution of a
nonlinear self-equilibrum system of the discrete lattice...
We prove the conical differentiability of the solution to a bone remodeling contact rod model, for given data (applied loads and rigid obstacle), with respect to small perturbations of the cross section of the rod. The proof is based on the special structure of the model, composed of a variational inequality coupled with an ordinary differential equation with respect to time. This structure enables the verification of the two following fundamental results: the polyhedricity of a modified displacement...
We prove the conical differentiability of the solution to a bone
remodeling contact rod model, for given data (applied loads and
rigid obstacle), with respect to small perturbations of the cross
section of the rod. The proof is based on the special structure of
the model, composed of a variational inequality coupled with an
ordinary differential equation with respect to time. This
structure enables the verification of the two following
fundamental results: the polyhedricity of a modified displacement
constraint...
In vivo visualization of cardiovascular structures is possible using medical images. However, one has to realize that the resulting 3D geometries correspond to in vivo conditions. This entails an internal stress state to be present in the in vivo measured geometry of e.g. a blood vessel due to the presence of the blood pressure. In order to correct for this in vivo stress, this paper presents an inverse method to restore the original zero-pressure geometry of a structure, and to recover the in vivo...
In the last years many efforts have been devoted to understand the stressmodulated growth of soft tissues. Recent theoretical achievements suggest that a component of the stress-growth coupling is tissue-independent and reads as an Eshelby-like tensor. In this paper we investigate the mathematical properties and the qualitative behavior predicted by equations that specialize that model under few simple assumptions. Equations strictly deduced from a dissipation principle are compared with heuristic...
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