Purpose – The purpose of this paper is to detail the design of a fractional controller which was developed for the suppression of the flexural vibrations of the first mode of a smart beam. Design/methodology/approach – During the design of the fractional controller, in addition to the classical control parameters such as the controller gain and the bandwidth; the order of the derivative effect ...

We apply the tools of the fractional calculus to introduce new fractional-order beam solutions to the paraxial wave equation that can be regarded as intermediate solutions between the known integral-order solutions. We restrict our attention to the fractionalization of the elegant and standard Hermite-Gaussian beams.

By means of an analytic model and numerical simulations we demonstrate that the wake of a waveguide damped cavity contains a persistent component which decays as tm3f2 and thus is dominant at sufficiently large values oft. Because there are scenarios for which the effect gives rise to unacceptable beam instability, it cannot be ignored, but it seems likely that such an outcome can be avoided wi...

We consider a family of damped quasi-Newton methods for solving unconstrained optimization problems. This family resembles that of Broyden with line searches, except that the change in gradients is replaced by a certain hybrid vector before updating the current Hessian approximation. This damped technique modifies the Hessian approximations so that they are maintained sufficiently positive defi...

In this paper, we introduce locally Lipschitz observation systems for nonlinear semigroups and show that they can be represented by an ‘admissible’ nonlinear output operator defined on a suitable subspace. In the semilinear case, this concept fits well to the Lebesgue extension known from linear system theory. Also in the semilinear case, we show robustness of exact observability near equilibri...

In this paper we consider the effect of boundary damping on a cantilevered Timoshenko beam with a rigid body attached to the free end. We establish the efficiency and accuracy of the finite element method for calculating the eigenvalues and eigenmodes. Although no conclusion could be drawn with regard to the stabilization of the system, interesting phenomena concerning the damped vibration spec...

We investigate a semilinear time-fractional damped wave equation in one dimension, posed bounded interval. The considered involves convection term and singular potentials on extremity of the A Dirichlet boundary condition depending time-variable is imposed. Using nonlinear capacity estimates, we establish sufficient conditions for nonexistence weak solutions to problem. In particular, when inde...