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Equazioni di bilancio della meccanica dei continui nell’ambito della teoria geometrica della misura

Alessandro Musesti (2004)

Bollettino dell'Unione Matematica Italiana

Si dà una presentazione della formulazione delle equazioni di bilancio della Meccanica dei Continui tramite l'approccio insiemistico (flussi e interazioni di Cauchy) e quello distribuzionale (potenze virtuali), illustrando i progressi ottenuti nell'indebolimento delle ipotesi, fino a comprendere campi tensoriali a divergenza misura. Si mostra poi come l'approccio attraverso il Principio delle potenze virtuali permetta di individuare il tensore degli sforzi anche nel caso di un corpo continuo dotato...

Fonctionnelles invariantes et courants basiques

A. Abouqateb, A. El Kacimi Alaoui (2000)

Studia Mathematica

Dans ce travail: (1) on caractérise l’espace C G des fonctionnelles invariantes par un groupe compact G opérant linéairement et continûment sur un espace vectoriel topologique localement convexe séparé et séquentiellement complet E plus précisément, on montre que C G est le dual topologique du sous-espace E G des vecteurs de E qui sont G-invariants. (2) On étudie les courants basiques sur une variété feuilletée (V,ℱ). On obtient alors, dans le cas où le feuilletage est associé à une action localement...

Functions with prescribed singularities

Giovanni Alberti, S. Baldo, G. Orlandi (2003)

Journal of the European Mathematical Society

The distributional k -dimensional Jacobian of a map u in the Sobolev space W 1 , k − 1 which takes values in the sphere S k − 1 can be viewed as the boundary of a rectifiable current of codimension k carried by (part of) the singularity of u which is topologically relevant. The main purpose of this paper is to investigate the range of the Jacobian operator; in particular, we show that any boundary M of codimension k can be realized as Jacobian of a Sobolev map valued in S k − 1 . In case M is polyhedral, the map we construct...

Gamma-convergence results for phase-field approximations of the 2D-Euler Elastica Functional

Luca Mugnai (2013)

ESAIM: Control, Optimisation and Calculus of Variations

We establish some new results about the Γ-limit, with respect to the L1-topology, of two different (but related) phase-field approximations { ℰ } , { ℰ ˜ } ℰ ε ε ,   x10ff65; ℰ ε ε of the so-called Euler’s Elastica Bending Energy for curves in the plane. In particular we characterize theΓ-limit as ε → 0 of ℰε, and show that in general the Γ-limits of ℰεand ℰ ˜ x10ff65; ℰ ε do not coincide on indicator functions of sets with non-smooth boundary. More precisely we show that the domain of theΓ-limit of ℰ ˜ x10ff65;...

Ground states in complex bodies

Paolo Maria Mariano, Giuseppe Modica (2009)

ESAIM: Control, Optimisation and Calculus of Variations

A unified framework for analyzing the existence of ground states in wide classes of elastic complex bodies is presented here. The approach makes use of classical semicontinuity results, Sobolev mappings and cartesian currents. Weak diffeomorphisms are used to represent macroscopic deformations. Sobolev maps and cartesian currents describe the inner substructure of the material elements. Balance equations for irregular minimizers are derived. A contribution to the debate about the role of the balance...

Ground states in complex bodies

Paolo Maria Mariano, Giuseppe Modica (2008)

ESAIM: Control, Optimisation and Calculus of Variations

A unified framework for analyzing the existence of ground states in wide classes of elastic complex bodies is presented here. The approach makes use of classical semicontinuity results, Sobolev mappings and Cartesian currents. Weak diffeomorphisms are used to represent macroscopic deformations. Sobolev maps and Cartesian currents describe the inner substructure of the material elements. Balance equations for irregular minimizers are derived. A contribution to the debate about the role of the balance...

Hölder regularity of three-dimensional minimal cones in ℝⁿ

Tien Duc Luu (2014)

Annales Polonici Mathematici

We show the local Hölder regularity of Almgren minimal cones of dimension 3 in ℝⁿ away from their centers. The proof is almost elementary but we use the generalized theorem of Reifenberg. In the proof, we give a classification of points away from the center of a minimal cone of dimension 3 in ℝⁿ, into types ℙ, 𝕐 and 𝕋. We then treat each case separately and give a local Hölder parameterization of the cone.

Currently displaying 41 – 60 of 152