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Boundary controllability of the finite-difference space semi-discretizations of the beam equation

Liliana León, Enrique Zuazua (2002)

ESAIM: Control, Optimisation and Calculus of Variations

We propose a finite difference semi-discrete scheme for the approximation of the boundary exact controllability problem of the 1-D beam equation modelling the transversal vibrations of a beam with fixed ends. First of all we show that, due to the high frequency spurious oscillations, the uniform (with respect to the mesh-size) controllability property of the semi-discrete model fails in the natural functional setting. We then prove that there are two ways of restoring the uniform controllability...

Boundary controllability of the finite-difference space semi-discretizations of the beam equation

Liliana León, Enrique Zuazua (2010)

ESAIM: Control, Optimisation and Calculus of Variations

We propose a finite difference semi-discrete scheme for the approximation of the boundary exact controllability problem of the 1-D beam equation modelling the transversal vibrations of a beam with fixed ends. First of all we show that, due to the high frequency spurious oscillations, the uniform (with respect to the mesh-size) controllability property of the semi-discrete model fails in the natural functional setting. We then prove that there are two ways of restoring the uniform controllability...

Boundary feedback stabilization of a three-layer sandwich beam : Riesz basis approach

Jun-Min Wang, Bao-Zhu Guo, Boumediène Chentouf (2006)

ESAIM: Control, Optimisation and Calculus of Variations

In this paper, we consider the boundary stabilization of a sandwich beam which consists of two outer stiff layers and a compliant middle layer. Using Riesz basis approach, we show that there is a sequence of generalized eigenfunctions, which forms a Riesz basis in the state space. As a consequence, the spectrum-determined growth condition as well as the exponential stability of the closed-loop system are concluded. Finally, the well-posedness and regularity in the sense of Salamon-Weiss class as...

Boundary feedback stabilization of a three-layer sandwich beam: Riesz basis approach

Jun-Min Wang, Bao-Zhu Guo, Boumediène Chentouf (2005)

ESAIM: Control, Optimisation and Calculus of Variations

In this paper, we consider the boundary stabilization of a sandwich beam which consists of two outer stiff layers and a compliant middle layer. Using Riesz basis approach, we show that there is a sequence of generalized eigenfunctions, which forms a Riesz basis in the state space. As a consequence, the spectrum-determined growth condition as well as the exponential stability of the closed-loop system are concluded. Finally, the well-posedness and regularity in the sense of Salamon-Weiss class as...

Boundary stabilization of the linear elastodinamic system by a Lyapunov-type method.

Rabah Bey, Amar Heminna, Jean-Pierre Lohéac (2003)

Revista Matemática Complutense

We propose a direct approach to obtain the boundary stabilization of the isotropic linear elastodynamic system by a natural feedback; this method uses local coordinates in the expression of boundary integrals as a main tool. It leads to an explicit decay rate of the energy function and requires weak geometrical conditions: for example, the spacial domain can be the difference of two star-shaped sets.

Bounds and estimates on the effective properties for nonlinear composites

Peter Wall (2000)

Applications of Mathematics

In this paper we derive lower bounds and upper bounds on the effective properties for nonlinear heterogeneous systems. The key result to obtain these bounds is to derive a variational principle, which generalizes the variational principle by P. Ponte Castaneda from 1992. In general, when the Ponte Castaneda variational principle is used one only gets either a lower or an upper bound depending on the growth conditions. In this paper we overcome this problem by using our new variational principle...

Bounds and numerical results for homogenized degenerated p -Poisson equations

Johan Byström, Jonas Engström, Peter Wall (2004)

Applications of Mathematics

In this paper we derive upper and lower bounds on the homogenized energy density functional corresponding to degenerated p -Poisson equations. Moreover, we give some non-trivial examples where the bounds are tight and thus can be used as good approximations of the homogenized properties. We even present some cases where the bounds coincide and also compare them with some numerical results.

Buckling of anisotropic shells. I

Anukul De (1983)

Aplikace matematiky

The formulation of differential equations of buckling problem of anisotropic cylindrical shell is presented here. The solution for anisotropic cylindrical shells without shear load in case of two way compression is found out from the differential equations formulated. The corresponding results for isotropic case are deduced as a particular case.

Buckling of anisotropic shells. II

Anukul De (1983)

Aplikace matematiky

The object of this paper is to find the solution of the differential equation of the buckling problem of anisotropic cylindrical shells with shear load in case of torsion of a long tube. The critical values of the shear load and the total torque are also found. The corresponding results for the isotropic case are deduced as a special case.

Buckling of beam-column problem of anisotropic cylindrical shells

Anukul De (1986)

Aplikace matematiky

The object of this paper is to formulate the differential equations in the beamcolumn problem of the buckling of anisotropic cylindrical shells, placed between the plates of a testing machine subject to an axial load P and a radial load H of sufficient magnitude to bring the expansion without constraint of the edges produced by P to zero deflection. The solution is obtained with necessary boundary conditions and the corresponding results for the isotropic case are deduced.

BV solutions of rate independent differential inclusions

Pavel Krejčí, Vincenzo Recupero (2014)

Mathematica Bohemica

We consider a class of evolution differential inclusions defining the so-called stop operator arising in elastoplasticity, ferromagnetism, and phase transitions. These differential inclusions depend on a constraint which is represented by a convex set that is called the characteristic set. For BV (bounded variation) data we compare different notions of BV solutions and study how the continuity properties of the solution operators are related to the characteristic set. In the finite-dimensional case...

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