A mixed system of differential equations as a mathematical model of vibrations of continuum-discrete mechanical systems.
A mountain pass method for the numerical solution of semilinear wave equations.
A self-adjoint “simultaneous crossing of the axis”.
Asymptotic analysis, in a thin multidomain, of minimizing maps with values in
Asymptotic behaviour for a phase-field model with hysteresis in one-dimensional thermo-visco-plasticity
The asymptotic behaviour for of the solutions to a one-dimensional model for thermo-visco-plastic behaviour is investigated in this paper. The model consists of a coupled system of nonlinear partial differential equations, representing the equation of motion, the balance of the internal energy, and a phase evolution equation, determining the evolution of a phase variable. The phase evolution equation can be used to deal with relaxation processes. Rate-independent hysteresis effects in the strain-stress...
Computation of Green's matrices for boundary value problems associated with a pair of mixed linear regular ordinary differential operators.
Conditions for periodic vibrations in a symmetric n-string
A symmetric N-string is a network of N ≥ 2 sections of string tied together at one common mobile extremity. In their equilibrium position, the sections of string form N angles of 2π/N at their junction point. Considering the initial and boundary value problem for small-amplitude oscillations perpendicular to the plane of the N-string at rest, we obtain conditions under which the solution will be periodic with an integral period.
Determining the relaxation kernel in nonlinear one-dimensional viscoelasticity.
Eliciting harmonics on strings
One may produce the qth harmonic of a string of length π by applying the 'correct touch' at the node during a simultaneous pluck or bow. This notion was made precise by a model of Bamberger, Rauch and Taylor. Their 'touch' is a damper of magnitude b concentrated at . The 'correct touch' is that b for which the modes, that do not vanish at , are maximally damped. We here examine the associated spectral problem. We find the spectrum to be periodic and determined by a polynomial of degree ....
Energy of the harmonics in a vibrating string after the impact of a hammer
In questa Nota vengono usati alcuni risultati precedentemente ottenuti - v. [4] e [5] - riguardanti l'urto di un martelletto rigido e di una corda elastica. Da essi possono dedursi le condizioni della corda - deformazione e atto di moto - all'istante in cui essa rimane libera dall'influenza del martelletto. È dunque possibile determinare mediante l'analisi di Fourier, i valori delle energie delle varie armoniche, i quali, com'è ben noto, determinano il timbro del suono emesso dalla corda (timbro...
Étude d'un modèle hyperbolique en dynamique des câbles
Global classical solutions to the Cauchy problem for a nonlinear wave equation.
Global existence and polynomial decay for a problem with Balakrishnan-Taylor damping
A viscoelastic Kirchhoff equation with Balakrishnan-Taylor damping is considered. Using integral inequalities and multiplier techniques we establish polynomial decay estimates for the energy of the problem. The results obtained in this paper extend previous results by Tatar and Zaraï [25].
Ingham-type inequalities and Riesz bases of divided differences
We study linear combinations of exponentials e^{iλ_nt} , λ_n ∈ Λ in the case where the distance between some points λ_n tends to zero. We suppose that the sequence Λ is a finite union of uniformly discrete sequences. In (Avdonin and Ivanov, 2001), necessary and sufficient conditions were given for the family of divided differences of exponentials to form a Riesz basis in space L^2 (0,T). Here we prove that if the upper uniform density of Λ is less than T/(2π), the family of divided differences can...
Kirchhoff-Carrier elastic strings in noncylindrical domains.
Nonlinear modeling of cables with flexural stiffness.
Observability and controllability for a vibrating string with dynamical boundary control.
On a nonlinear equation of the vibrating string
A nonlinear model of the vibrating string is studied and global existence and uniqueness theorems for the solution of the Cauchy-Dirichlet problem are given. The model is then compared to the classical D'Alembert model and to a nonlinear model due to Kirchhoff.
On a variational inequality for the nonhomogeneous degenerated Kirchhoff equation with a frictional damping.
On global real analytic solutions of the degenerate Kirchhoff equation