Displaying 21 – 40 of 65

Showing per page

Homogenization in perforated domains with rapidly pulsing perforations

Doina Cioranescu, Andrey L. Piatnitski (2003)

ESAIM: Control, Optimisation and Calculus of Variations

The aim of this paper is to study a class of domains whose geometry strongly depends on time namely. More precisely, we consider parabolic equations in perforated domains with rapidly pulsing (in time) periodic perforations, with a homogeneous Neumann condition on the boundary of the holes. We study the asymptotic behavior of the solutions as the period ε of the holes goes to zero. Since standard conservation laws do not hold in this model, a first difficulty is to get a priori estimates of the...

Homogenization in perforated domains with rapidly pulsing perforations

Doina Cioranescu, Andrey L. Piatnitski (2010)

ESAIM: Control, Optimisation and Calculus of Variations

The aim of this paper is to study a class of domains whose geometry strongly depends on time namely. More precisely, we consider parabolic equations in perforated domains with rapidly pulsing (in time) periodic perforations, with a homogeneous Neumann condition on the boundary of the holes. We study the asymptotic behavior of the solutions as the period ε of the holes goes to zero. Since standard conservation laws do not hold in this model, a first difficulty is to get a priori estimates...

Homogenization of a singular random one-dimensional PDE

Bogdan Iftimie, Étienne Pardoux, Andrey Piatnitski (2008)

Annales de l'I.H.P. Probabilités et statistiques

This paper deals with the homogenization problem for a one-dimensional parabolic PDE with random stationary mixing coefficients in the presence of a large zero order term. We show that under a proper choice of the scaling factor for the said zero order terms, the family of solutions of the studied problem converges in law, and describe the limit process. It should be noted that the limit dynamics remain random.

Homogenization of evolution problems for a composite medium with very small and heavy inclusions

Michel Bellieud (2005)

ESAIM: Control, Optimisation and Calculus of Variations

We study the homogenization of parabolic or hyperbolic equations like ρ ε n u ε t n - div ( a ε u ε ) = f in Ω × ( 0 , T ) + boundary conditions , n { 1 , 2 } , when the coefficients ρ ε , a ε (defined in Ø ) take possibly high values on a ε -periodic set of grain-like inclusions of vanishing measure. Memory effects arise in the limit problem.

Homogenization of evolution problems for a composite medium with very small and heavy inclusions

Michel Bellieud (2010)

ESAIM: Control, Optimisation and Calculus of Variations

We study the homogenization of parabolic or hyperbolic equations like ρ ε n u ε t n - div ( a ε u ε ) = f in Ø × ( 0 , T ) + boundary conditions , n { 1 , 2 } , when the coefficients ρ ε , a ε (defined in Ω) take possibly high values on a ε-periodic set of grain-like inclusions of vanishing measure. Memory effects arise in the limit problem.

Homogenization of highly oscillating boundaries and reduction of dimension for a monotone problem

Dominique Blanchard, Antonio Gaudiello (2010)

ESAIM: Control, Optimisation and Calculus of Variations

We investigate the asymptotic behaviour, as ε → 0, of a class of monotone nonlinear Neumann problems, with growth p-1 (p ∈]1, +∞[), on a bounded multidomain Ω ε N (N ≥ 2). The multidomain ΩE is composed of two domains. The first one is a plate which becomes asymptotically flat, with thickness hE in the xN direction, as ε → 0. The second one is a “forest" of cylinders distributed with ε-periodicity in the first N - 1 directions on the upper side of the plate. Each cylinder has a small...

Homogenization of linear elasticity equations

Jan Franců (1982)

Aplikace matematiky

The homogenization problem (i.e. the approximation of the material with periodic structure by a homogeneous one) for linear elasticity equation is studied. Both formulations in terms of displacements and in terms of stresses are considered and the results compared. The homogenized equations are derived by the multiple-scale method. Various formulae, properties of the homogenized coefficients and correctors are introduced. The convergence of displacment vector, stress tensor and local energy is proved...

Homogenization of many-body structures subject to large deformations

Philipp Emanuel Stelzig (2012)

ESAIM: Control, Optimisation and Calculus of Variations

We give a first contribution to the homogenization of many-body structures that are exposed to large deformations and obey the noninterpenetration constraint. The many-body structures considered here resemble cord-belts like they are used to reinforce pneumatic tires. We establish and analyze an idealized model for such many-body structures in which the subbodies are assumed to be hyperelastic with a polyconvex energy density and shall exhibit an initial brittle bond with their neighbors. Noninterpenetration...

Homogenization of many-body structures subject to large deformations

Philipp Emanuel Stelzig (2012)

ESAIM: Control, Optimisation and Calculus of Variations

We give a first contribution to the homogenization of many-body structures that are exposed to large deformations and obey the noninterpenetration constraint. The many-body structures considered here resemble cord-belts like they are used to reinforce pneumatic tires. We establish and analyze an idealized model for such many-body structures in which the subbodies are assumed to be hyperelastic with a polyconvex energy density and shall exhibit an...

Homogenization of micromagnetics large bodies

Giovanni Pisante (2004)

ESAIM: Control, Optimisation and Calculus of Variations

A homogenization problem related to the micromagnetic energy functional is studied. In particular, the existence of the integral representation for the homogenized limit of a family of energies ε ( m ) = Ω φ x , x ε , m ( x ) d x - Ω h e ( x ) · m ( x ) d x + 1 2 3 | u ( x ) | 2 d x of a large ferromagnetic body is obtained.

Homogenization of micromagnetics large bodies

Giovanni Pisante (2010)

ESAIM: Control, Optimisation and Calculus of Variations

A homogenization problem related to the micromagnetic energy functional is studied. In particular, the existence of the integral representation for the homogenized limit of a family of energies ε ( m ) = Ω φ x , x ε , m ( x ) d x - Ω h e ( x ) · m ( x ) d x + 1 2 3 | u ( x ) | 2 d x of a large ferromagnetic body is obtained.

Homogenization of parabolic equations an alternative approach and some corrector-type results

Anders Holmbom (1997)

Applications of Mathematics

We extend and complete some quite recent results by Nguetseng [Ngu1] and Allaire [All3] concerning two-scale convergence. In particular, a compactness result for a certain class of parameterdependent functions is proved and applied to perform an alternative homogenization procedure for linear parabolic equations with coefficients oscillating in both their space and time variables. For different speeds of oscillation in the time variable, this results in three cases. Further, we prove some corrector-type...

Homogenization of periodic non self-adjoint problems with large drift and potential

Grégoire Allaire, Rafael Orive (2007)

ESAIM: Control, Optimisation and Calculus of Variations

We consider the homogenization of both the parabolic and eigenvalue problems for a singularly perturbed convection-diffusion equation in a periodic medium. All coefficients of the equation may vary both on the macroscopic scale and on the periodic microscopic scale. Denoting by ε the period, the potential or zero-order term is scaled as ε - 2 and the drift or first-order term is scaled as ε - 1 . Under a structural hypothesis on the first cell eigenvalue, which is assumed to admit a unique minimum in the...

Currently displaying 21 – 40 of 65