Error estimates for elasto-plastic problems
Error estimates for the Coupled Cluster method
The Coupled Cluster (CC) method is a widely used and highly successful high precision method for the solution of the stationary electronic Schrödinger equation, with its practical convergence properties being similar to that of a corresponding Galerkin (CI) scheme. This behaviour has for the discrete CC method been analyzed with respect to the discrete Galerkin solution (the “full-CI-limit”) in [Schneider, 2009]. Recently, we globalized the CC formulation to the full continuous space, giving a root...
Error estimates for the ultra weak variational formulation in linear elasticity
We prove error estimates for the ultra weak variational formulation (UWVF) in 3D linear elasticity. We show that the UWVF of Navier’s equation can be derived as an upwind discontinuous Galerkin method. Using this observation, error estimates are investigated applying techniques from the theory of discontinuous Galerkin methods. In particular, we derive a basic error estimate for the UWVF in a discontinuous Galerkin type norm and then an error estimate in the L2(Ω) norm in terms of the best approximation...
Error estimates for the ultra weak variational formulation in linear elasticity∗
We prove error estimates for the ultra weak variational formulation (UWVF) in 3D linear elasticity. We show that the UWVF of Navier’s equation can be derived as an upwind discontinuous Galerkin method. Using this observation, error estimates are investigated applying techniques from the theory of discontinuous Galerkin methods. In particular, we derive a basic error estimate for the UWVF in a discontinuous Galerkin type norm and then an error estimate...
Error estimates of a numerical method for a class of nonlinear evolution equations
Error estimates of an iterative method for a quasistatic elastic-visco-plastic problem
This paper deals with an initial and boundary value problem describing the quasistatic evolution of rate-type viscoplastic materials. Using a fixed point property, an iterative method in the study of this problem is proposed. A concrete algorithm as well as some numerical results in the one-dimensional case are also presented.
Error estimation and adaptivity for nonlinear FE analysis
An adaptive strategy for nonlinear finite-element analysis, based on the combination of error estimation and h-remeshing, is presented. Its two main ingredients are a residual-type error estimator and an unstructured quadrilateral mesh generator. The error estimator is based on simple local computations over the elements and the so-called patches. In contrast to other residual estimators, no flux splitting is required. The adaptive strategy is illustrated by means of a complex nonlinear problem:...
Esistenza e unicità della soluzione nella statica di solidi termoelastici incomprimibili
In this work we prove that the thermoelastic equilibrium problem in the context of the linear theory for thermoelastic incompressible solids has one and only one solution.
Essai de «thermodynamique rationnelle» des milieux continus
Estensione a leggi costitutive a variabili interne dei teoremi di inadattamento in dinamica strutturale elastoplastica
Si considera il problema del mancato adattamento in campo dinamico per strutture elasto-plastiche incrudenti. Si dimostrano una condizione necessaria ed una sufficiente per il verificarsi di fenomeni di inadattamento (plasticità alternata o collasso incrementale) estendendo risultati precedenti ad un'ampia classe di modelli costitutivi a variabili interne in grado di rappresentare comportamenti incrudenti non lineari.
Estensione di un teorema sull'adattamento in dinamica elasto-plastica
Nell'articolo si tratta il problema dell'adattamento in dinamica elasto-plastica. La trattazione è fondata sulle seguenti basi: si adotta un legame costitutivo elasto-plastico di notevole generalità, basato su di una formulazione a variabili interne in grado di descrivere un comportamento incrudente genericamente non lineare; si fa riferimento ad un modello strutturale discreto, descritto mediante variabili generalizzate. I contributi presentati si possono così riassumere: si estendono risultati...
Estimates for second order derivatives of eigenvectors in thin anisotropic plates with variable thickness.
Estimates from above and from below for the Homogenized Coefficients.
Estimation du taux de décroissance pour la solution de problèmes de stabilisation, application à la stabilisation de l'équation des ondes
Estimation of EDZ zones in great depths by elastic-plastic models
This contribution is devoted to modeling damage zones caused by the excavation of tunnels and boreholes (EDZ zones) in connection with the issue of deep storage of spent nuclear fuel in crystalline rocks. In particular, elastic-plastic models with Mohr-Coulomb or Hoek-Brown yield criteria are considered. Selected details of the numerical solution to the corresponding problems are mentioned. Possibilities of elastic and elastic-plastic approaches are illustrated by a numerical example.
Estimation of vibration frequencies of linear elastic membranes
The free motion of a thin elastic linear membrane is described, in a simplyfied model, by a second order linear homogeneous hyperbolic system of partial differential equations whose spatial part is the Laplace Beltrami operator acting on a Riemannian 2-dimensional manifold with boundary. We adapt the estimates of the spectrum of the Laplacian obtained in the last years by several authors for compact closed Riemannian manifolds. To make so, we use the standard technique of the doubled manifold to...
Estimations d'erreur pour des éléments finis droits presque dégénérés
Etude asymptotique de la jonction d'un massif tridimensionnel et d'une tige élancée en flexion.
We are very interested with asymptotic problems for the system of elasticity involving small parameters in the description of the domain where the solutions is searched. The corresponding asymptotic expansions have different forms in the various between them. More precisely, our work is concerned with a precise description of the deformation and the stress fields at the junction of an elastic three-dimensional body and a cylinder. The corresponding small parameter is the diameter of the cylinder....
Étude dans d’un modèle de plaques élastoplastiques comportant une non-linéarité géométrique
Étude de deux schémas numériques pour les équations de la thermoélasticité