Decay estimates for solutions of some systems for elasticity with nonlinear boundary feedback.
Deformazioni finite di blocchi elastici incomprimibili: una soluzione esatta per appoggi in gomma semplicemente compressi
In questo articolo si studia un problema misto al contorno associato con le deformazioni finite di un parallelepipedo elastico incomprimibile, omogeneo ed isotropo. L'analisi è rivolta allo studio degli appoggi in gomma nelle costruzioni. In particolare, usando il metodo semi-inverso, viene fornita una soluzione esatta del problema di equilibrio degli appoggi semplicemente compressi. Inoltre, per ragioni di interesse tecnico, viene proposta una nuova relazione globale «carico-schiacciamento », che...
Direct approach to mean-curvature flow with topological changes
This contribution deals with the numerical simulation of dislocation dynamics. Dislocations are described by means of the evolution of a family of closed or open smooth curves , . The curves are driven by the normal velocity which is the function of curvature and the position. The evolution law reads as: . The motion law is treated using direct approach numerically solved by two schemes, i. e., backward Euler semi-implicit and semi-discrete method of lines. Numerical stability is improved...
Dislocation dynamics - analytical description of the interaction force between dipolar loops
The interaction between dislocation dipolar loops plays an important role in the computation of the dislocation dynamics. The analytical form of the interaction force between two loops derived in the present paper from Kroupa’s formula of the stress field generated by a single dipolar loop allows for faster computation.
Dissipatività e unicità per il problema dinamico unidimensionale della viscoelasticità lineare
Fissato lo spazio di Sobolev come ambiente del problema dinamico per un corpo viscoelastico unidimensionale si dimostra un teorema di unicità per la classe delle funzioni di rilassamento convesse. Si fa inoltre vedere come tale unicità sia strettamente legata allo spazio ambiente considerato.
Dissipatività ed esistenza per il problema dinamico unidimensionale della viscoelasticità lineare
In questa nota si completa la studio (iniziato in [1]) della caratterizzazione delle funzioni di rilassamento per le quali il problema dinamico della viscoelasticità lineare, con condizioni di spostamento nullo agli estremi, risulta ben posto nello spazio di Sobolev . Precisamente, per un'opportuna classe di sollecitazioni esterne, si dimostra l'esistenza della soluzione, se le funzioni di rilassamento sono positive, convesse ed hanno il modulo di elasticità all'equilibrio strettamente maggiore...
Drive network to a desired orbit by pinning control
The primary objective of the present paper is to develop an approach for analyzing pinning synchronization stability in a complex delayed dynamical network with directed coupling. Some simple yet generic criteria for pinning such coupled network are derived analytically. Compared with some existing works, the primary contribution is that the synchronization manifold could be chosen as a weighted average of all the nodes states in the network for the sake of practical control tactics, which displays...
Dynamic analysis of viscous material models
The article deals with the analysis of the dynamic behavior of a~concrete structural element during fast dynamic processes. The constitutive material model must be chosen appropriately so that it takes material viscosity into account when describing the behavior of material. In this analysis, it is necessary to use fairly complex viscous material models which can affect, for example, vibration damping and the dependence of strength or even of the entire stress-strain curve on the strain rate. These...
Dynamic boundary controls of a rotating body-beam system with time-varying angular velocity.
Dynamic contact problems with given friction for viscoelastic bodies
Dynamic contact problems with slip-dependent friction in viscoelasticity
The dynamic evolution with frictional contact of a viscoelastic body is considered. The assumptions on the functions used in modelling the contact are broad enough to include both the normal compliance and the Tresca models. The friction law uses a friction coefficient which is a non-monotone function of the slip. The existence and uniqueness of the solution are proved in the general three-dimensional case.
Dynamic contact problems with velocity conditions
We consider dynamic problems which describe frictional contact between a body and a foundation. The constitutive law is viscoelastic or elastic and the frictional contact is modelled by a general subdifferential condition on the velocity, including the normal damped responses. We derive weak formulations for the models and prove existence and uniqueness results. The proofs are based on the theory of second-order evolution variational inequalities. We show that the solutions of the viscoelastic problems...
Dynamic contact with Signorini's condition and slip rate dependent friction.
Dynamic Damping - Comparison of different concepts from the point of view of their physical nature and effects on civil engineering structures
Sources of dynamic damping may be various. Mostly, the damping is implemented into calculations in a form of introduction of damping forces, as a product of the velocity vector and the damping matrix in an equation of motion. In practice, the damping matrix is usually assumed to be a linear combination of the mass matrix and the stiffness matrix (so called Rayleigh’s damping). This kind of damping primarily assumes the external environment viscosity as the source of damping, even though the part...
Dynamic frictional contact for elastic viscoplastic material.
Dynamic frictional contact of a viscoelastic beam
In this paper, we study the dynamic frictional contact of a viscoelastic beam with a deformable obstacle. The beam is assumed to be situated horizontally and to move, in both horizontal and tangential directions, by the effect of applied forces. The left end of the beam is clamped and the right one is free. Its horizontal displacement is constrained because of the presence of a deformable obstacle, the so-called foundation, which is modelled by a normal compliance contact condition. The effect...
Dynamic stability of functionally graded plate under in-plane compression.
Dynamic von Kármán equations involving nonlinear damping: Time-periodic solutions
In the paper, time-periodic solutions to dynamic von Kármán equations are investigated. Assuming that there is a damping term in the equations we are able to show the existence of at least one solution to the problem. The Faedo-Galerkin method is used together with some basic ideas concerning monotone operators on Orlicz spaces.
Dynamical interaction of an elastic system and a vibro-impact absorber.
Dynamics of flexible shells and Sharkovskiy's periodicity.