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Hybrid level set phase field method for topology optimization of contact problems

Andrzej Myśliński, Konrad Koniarski (2015)

Mathematica Bohemica

The paper deals with the analysis and the numerical solution of the topology optimization of system governed by variational inequalities using the combined level set and phase field rather than the standard level set approach. The standard level set method allows to evolve a given sharp interface but is not able to generate holes unless the topological derivative is used. The phase field method indicates the position of the interface in a blurry way but is flexible in the holes generation. In the...

Hypersingular integral equations and applications to porous elastic materials with periodic cracks

Michele Ciarletta, Gerardo Iovane (2005)

Bollettino dell'Unione Matematica Italiana

In this work a treatment of hypersingular integral equations, which have relevant applications in many problems of wave dynamics, elasticity and fluid mechanics with mixed boundary conditions, is presented. The first goal of the present study is the development of an efficient analytical and direct numerical collocation method. The second one is the application of the method to the porous elastic materials when a periodic array of co-planar cracks is present. Starting from Cowin- Nunziato model...

Hysteresis filtering in the space of bounded measurable functions

Pavel Krejčí, Philippe Laurençot (2002)

Bollettino dell'Unione Matematica Italiana

We define a mapping which with each function u ∈ L ∞ ⁢ 0 , T and an admissible value of r > 0 associates the function ξ with a prescribed initial condition ξ 0 which minimizes the total variation in the r -neighborhood of u in each subinterval 0 , t of 0 , T . We show that this mapping is non-expansive with respect to u , r and ξ 0 , and coincides with the so-called play operator if u is a regulated function.

I difficili rapporti fra l'Analisi funzionale e la Fisica Matematica

Gaetano Fichera (1990)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

— Si mostra come la scelta di una topologia nello spazio delle funzioni ammissibili, in taluni problemi, influenzi i relativi risultati. Vengono mostrati tre esempi. Due tratti dall'Analisi matematica pura: uno riguardante la stabilità della soluzione di un'equazione integrale di Volterra e l'altro il problema di Cauchy per l'equazione di Laplace come «problema ben posto». Il terzo esempio è relativo alla Fisica matematica, precisamente al «Principio della Memoria evanescente» in Viscoelasticità....

Identification problem for nonlinear beam -- extension for different types of boundary conditions

Radová, Jana, Machalová, Jitka (2023)

Programs and Algorithms of Numerical Mathematics

Identification problem is a framework of mathematical problems dealing with the search for optimal values of the unknown coefficients of the considered model. Using experimentally measured data, the aim of this work is to determine the coefficients of the given differential equation. This paper deals with the extension of the continuous dependence results for the Gao beam identification problem with different types of boundary conditions by using appropriate analytical inequalities with a special...

Il criterio dell'energia e l'equazione di Maxwell-Cattaneo nella termoelasticità non lineare

Ettore Laserra, Giovanni Matarazzo (1985)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

By means of the energy method we determine the behaviour of the canonical free energy of an elastic body, immersed in an environment that is thermally and mechanically passive; we use as constitutive equation for the heat flux a Maxwell-Cattaneo like equation.

Il problema monolaterale di contatto dinamico con attrito di una trave su una fondazione alla Hetényi: un approccio agli elementi finiti

Luigi Ascione, Giancarlo Bilotti (1988)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

L'ipotesi di contatto monolaterale tra strutture di fondazione e terreno assume un significato importante in tutti quei problemi tecnici, nei quali l'area di contatto tra struttura e fondazione diviene percentualmente piccola, sia per la rigidezza relativa dei corpi a contatto, sia per la condizione di carico, soprattutto in presenza di carichi ribaltanti come possono adesempio essere le forze sismiche. In questo contesto sono stati sviluppati negli ultimi anni diversi studi, che riguadano però...

Immersed boundary methods for the numerical simulation of incompressible aerodynamics and fluid-structure interactions

Nicolas James, Emmanuel Maitre, Iraj Mortazavi (2013)

Annales mathématiques Blaise Pascal

In this work three branches of Immersed Boundary Methods (IBM) are described and validated for incompressible aerodynamics and fluid-structure interactions. These three approaches are: Cut Cell method, Vortex-Penalization method and Forcing method. The first two techniques are validated for external bluff-body flow around a circular obstacle. The last one is used to predict the deformations of an elastic membrane immersed in a fluid. The paper confirms the ability of this family of numerical schemes...

Implicit constitutive solution scheme for Mohr-Coulomb plasticity

Sysala, Stanislav, Čermák, Martin (2017)

Programs and Algorithms of Numerical Mathematics

This contribution summarizes an implicit constitutive solution scheme of the elastoplastic problem containing the Mohr-Coulomb yield criterion, a nonassociative flow rule, and a nonlinear isotropic hardening. The presented scheme builds upon the subdifferential formulation of the flow rule leading to several improvements. Mainly, it is possible to detect a position of the unknown stress tensor on the Mohr-Coulomb pyramid without blind guesswork. Further, a simplified construction of the consistent...

Impulsive practical synchronization of n-dimensional nonautonomous systems with parameter mismatch

Mihua Ma, Hua Zhang, Jianping Cai, Jin Zhou (2013)

Kybernetika

This paper is concerned with impulsive practical synchronization in a class of n-dimensional nonautonomous dynamical systems with parameter mismatch. Some simple yet general algebraic synchronization criteria are derived based on the developed practical stability theory on impulsive dynamical systems. A distinctive feature of this work is that the impulsive control strategy is used to make n-dimensional nonautonomous dynamical systems with parameter mismatch achieve practical synchronization, where...

Currently displaying 1021 – 1040 of 2623