Aims. We present an analytic approximate seismic inversion scheme for damped transverse coronal loop oscillations based on the thin tube and thin boundary approximation for computing the period and the damping time. Methods. Asymptotic expressions for the period and damping rate are used to illustrate the process of seismological inversion in a simple and easy to follow manner. The inversion pr...

In this paper, the periodic, quasi periodic and chaotic responses of rotational machines with a hexagonal centrifugal governor are studied. The external disturbance is assumed as a sinusoid effect. By using the forth order Rung-Kutta numerical integration method, bifurcation diagram, largest Lyapunov exponent and Lyapunov dimension are calculated and presented to detect the critical controlling...

In this paper we nd a characterization for when a multivariable trigonometric polynomial can be written as a sum of squares. In addition, the truncated moment problem is addressed. A numerical algorithm for nding a sum of squares representation is presented as well. In the one-variable case, the algorithm nds a spectral factorization. The latter may also be used to nd inner-outer factor-izations.

The modal testing has proven to be an effective and non-destructive test method for estimation of the dynamic stiffness and damping constant. The aim of the present paper is to investigate the modal response of stiffened Fiber Metal Laminated (FML) circular cylindrical shells using experimental and numerical techniques. For this purpose, three types of FML-stiffened shells are fabricated by a s...

iii Abstract The goal of this research is to provide a framework for vibro-acoustical analysis and design of a multiple-layer constrained damping structure. The existing research on damping and viscoelastic damping mechanism is limited to the following four mainstream approaches: modeling techniques of damping treatments/materials; control through the electrical-mechanical effect using the piez...

The asymptotic behavior of dissipative hyperbolic systems is very sensitive to the precise nature of the dissipation. Dry (Coulomb) friction is a limit case that has not been fully analyzed, for instance with respect to the asymptotic time behavior of solutions. Examples of such a problem are given by simple models of granular materials in containers. A numerical approach for generic problems o...

When solving numerically the stiff second order ODE system obtained after semidiscretizing the wave-type partial differential equation (PDE) with the finite element method (FEM), and similarly to the HHTα method, which allows the numerical damping of the undesirable high frequency modes associated to FEM semidiscretization, we have constructed a modification of the 2-order BDF method (the BDF2 ...

A numerical model is constructed for modelling macroscale damping e ects induced by the rst order martensite phase transformations in a shape memory alloy rod. The model is constructed on the basis of the modi ed Landau-Ginzburg theory that couples nonlinear mechanical and thermal elds. The free energy function for the model is constructed as a double well function at low temperature, such that...

The goal of the research described in this paper is to investigate the feasibility of a new combined polymer composite damping system, which consists of a polymer honeycomb material and a viscoelastic solid material. This new combined viscoelastic system, which is intended primarily for energy dissipation and vibration control, serves as an interface layer within lightweight composite panels su...

Abstract. We consider a damped linear wave equation defined on a bi-dimensional domain Ω. Due to the damping term defined on the sub-domain ω ⊂ Ω, the system is dissipative. We address the problem of the optimal position and shape design of the support ω in order to minimize the energy of the system at a given time T . Introducing an adjoint problem we first obtain explicitly the (shape) deriva...