All a b c d e f g h i j k l m n o p q r s t u v w x y z Other

Previous Page 3 Next

Displaying 41 – 60 of 88

Showing per page

On the existence of a weak solution of the boundary value problem for the equilibrium of a shallow shell reinforced with stiffening ribs

Igor Bock, Ján Lovíšek (1978)

Aplikace matematiky

The existence and the unicity of a weak solution of the boundary value problem for a shallow shell reinforced with stiffening ribs is proved by the direct variational method. The boundary value problem is solved in the space W ( Ω ) ⊂ H 0 1 ( Ω ) × H 0 1 ( Ω ) × H 0 2 ( Ω ) , on which the corresponding bilinear form is coercive. A finite element method for numerical solution is introduced. The approximate solutions converge to a weak solution in the space Q ( Ω ) .

On the mechanical behaviour of laminated curved beams: a simple model which takes into account the warping effects

Luigi Ascione, Fernando Fraternali (1990)

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

A mechanical one-dimensional model which describes the dynamical behaviour of laminated curved beams is formulated. It is assumed that each lamina can be regarded as a Timoshenko's beam and that the rotations of the cross sections can differ from one lamina to another. The relative displacements at the interfaces of adjacent laminae are assumed to be zero. Consequently the model includes a shear deformability, due to the warping of the cross beam section consequent to the variability of the laminae...

On the membrane approximation for thin elastic shells in the hyperbolic case.

E. Sánchez-Palencia (1993)

Revista Matemática de la Universidad Complutense de Madrid

We consider the variational formulation of the problem of elastic shells in the membrane approximation, when the medium surface is hyperbolic. It appears that the corresponding bilinear form behaves as some kind of two-dimensional elasticity without shear rigidity. This amounts to saying that the membrane behaves rather as a net made of elastic strings disposed along the asymptotic curves of the surface than as an elastic two-dimensional medium. The mathematical and physical reasons of this behavior...

On the minimum of the work of interaction forces between a pseudoplate and a rigid obstacle

Igor Bock, Ján Lovíšek (2001)

Mathematica Bohemica

An optimization problem for the unilateral contact between a pseudoplate and a rigid obstacle is considered. The variable thickness of the pseudoplate plays the role of a control variable. The cost functional is a regular functional only in the smooth case. The existence of an optimal thickness is verified. The penalized optimal control problem is considered in the general case.

On the nonlifiear theory of beams with open thin sections

Placido Cicala (1987)

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

Analysis of beam with thin open sections as cylindrical shells evidences restrictions of the Wagner-Vlasof theory: these mainly concern the fulfillment of end conditions. For the case of large deflections, the resultant equations from asymptotic analysis are presented. Their application to buckling under pure flexure shows various novel aspects. By a simple direct approach, investigation is pursued beyond the critical state: the buckled configuration turns out to be stable even for laxer constraints...

On the nonlinear behaviour of bimodular multilayer ed plates.

Giacinto Porco, Giuseppe Spandea, Raffaele Zinno (1991)

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

In an earlier study [16] the nonlinear behaviour of unimodular laminated plates was studied. This paper, following the previous study, concerns a large deflection analysis of moderately thick rectangular plates having arbitrary boundary conditions and finite thickness shear moduli. The plates are manufactured in bimodular materials and constructed in a cross-ply fashion or in a single layer with arbitrary fibre direction angle. Numerical results are obtained by a finite element technique in which...

On the numerical modeling of deformations of pressurized martensitic thin films

Pavel Bělík, Timothy Brule, Mitchell Luskin (2001)

ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique

We propose, analyze, and compare several numerical methods for the computation of the deformation of a pressurized martensitic thin film. Numerical results have been obtained for the hysteresis of the deformation as the film transforms reversibly from austenite to martensite.

On the Numerical Modeling of Deformations of Pressurized Martensitic Thin Films

Pavel Bělík, Timothy Brule, Mitchell Luskin (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

We propose, analyze, and compare several numerical methods for the computation of the deformation of a pressurized martensitic thin film. Numerical results have been obtained for the hysteresis of the deformation as the film transforms reversibly from austenite to martensite.

On the optimal control problem governed by the equations of von Kármán. II. Mixed boundary conditions

Igor Bock, Ivan Hlaváček, Ján Lovíšek (1985)

Aplikace matematiky

A control of the system of Kármán's equations for a thin elastic plate is considered. Existence of an optimal transversal load and optimal stress function, respectively, is proven. The set of admissible functions is chosen in a way guaranteeing the unique solvability of the state problem. The differentiability of the state function with respect to the control variable, uniqueness of the optimal control and some necessary conditions of optimality are discussed.

On the optimal control problem governed by the equations of von Kármán. I. The homogeneous Dirichlet boundary conditions

Igor Bock, Ivan Hlaváček, Ján Lovíšek (1984)

Aplikace matematiky

A control of the system of nonlinear Kármán's equations for a thin elastic plate with clamped edge is considered. The transversal loading plays the role of the control variable. The set of admissible controls is chosen in a way guaranteeing the unique solvability of the state function with respect to the control variable is proved. A disscussion of uniqueness of the optimal control and some necessary conditions of optimality are presented.

On the optimal control problem governed by the equations of von Kármán. III. The case of an arbitrary large perpendicular load

Igor Bock, Ivan Hlaváček, Ján Lovíšek (1987)

Aplikace matematiky

We shall deal with an optimal control problem for the deffection of a thin elastic plate. We consider the perpendicular load on the plate as the control variable. In contrast to the papers [1], [2], arbitrarily large loads are edmitted. As the unicity of a solution of the state equation is not guaranteed, we consider the cost functional defined on the set of admissible controls and states, and the state equation plays the role of the constraint. The existence of an optimal couple (i.e., control...

On the solution of a finite element approximation of a linear obstacle plate problem

Luis Fernandes, Isabel Figueiredo, Joaquim Júdice (2002)

International Journal of Applied Mathematics and Computer Science

In this paper the solution of a finite element approximation of a linear obstacle plate problem is investigated. A simple version of an interior point method and a block pivoting algorithm have been proposed for the solution of this problem. Special purpose implementations of these procedures are included and have been used in the solution of a set of test problems. The results of these experiences indicate that these procedures are quite efficient to deal with these instances and compare favourably...

Currently displaying 41 – 60 of 88