123,053 research outputs found
Numerical analysis of a transmission problem with Signorini contact using mixed-FEM and BEM
No full text© EDP Sciences, SMAI 2011This paper is concerned with the dual formulation of the interface problem consisting of a linear partial differential equation with variable coefficients in some bounded Lipschitz domain Ω in
Rn (n ≥ 2) and the Laplace equation with some radiation condition in the unbounded exterior domain Ωc := Rn\￣Ω. The two problems are coupled by transmission and Signorini contact conditions on the interface Γ = ∂Ω. The exterior part of the interface problem is rewritten using a Neumann to Dirichlet mapping (NtD) given in terms of boundary integral operators. The resulting variational formulation becomes a variational inequality with a linear operator. Then we treat the corresponding numerical scheme and discuss an approximation of the NtD mapping with an appropriate discretization of the inverse Poincar´e-Steklov operator. In particular, assuming some abstract approximation properties and a discrete inf-sup condition, we show unique solvability of the discrete scheme and obtain the corresponding a-priori error estimate. Next, we prove that these assumptions are satisfied with Raviart- Thomas elements and piecewise constants in Ω, and continuous piecewise linear functions on Γ. We suggest a solver based on a modified Uzawa algorithm and show convergence. Finally we present some numerical results illustrating our theory
Scrivere, leggere, conservare. A colloquio con Armando Petrucci
No full textThis monographic issue of the periodical "Studj romanzi" is dedicated to the palaeographical method introduced by Armando Petrucci and to the relationships of that wide method of scientific investigation with other branch of knowledge such as romance philology and linguisti
Boundary augmented Lagrangian method for the Signorini problem
No full textsummary:An augmented Lagrangian method, based on boundary variational formulations and fixed point method, is designed and analyzed for the Signorini problem of the Laplacian. Using the equivalence between Signorini boundary conditions and a fixed-point problem, we develop a new iterative algorithm that formulates the Signorini problem as a sequence of corresponding variational equations with the Steklov-Poincaré operator. Both theoretical results and numerical experiments show that the method presented is efficient
Une recherche sur les manuscrits à cahiers mixtes.
No full textBianchi Francesco, Canart Paul, d'Agostino Marco, Lucchini Lucia, Magrini Sabina, Maniaci Marilena, Orsatti Paola, Palma Marco, Signorini Maddalena. Une recherche sur les manuscrits à cahiers mixtes. In: Scriptorium, Tome 48 n°2, 1994. pp. 259-286
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