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Abstracts of papers for

Previous issue vol. 48, no. 3 (2000)

vol. 48, no. 4 (2000)

Next issue vol. 49, no. 1 (2001)

Contents of issue 4, vol. 48

1. A. Garstecki, W. Kąkol, K. Rzeszut: Analysis of thin-walled bars with open and closed-open cross-sections
2. R. Korycki: Identification of the material phases location for the one-dimensional unsteady heat conduction problem
3. J. Marcinowski: Static and stability analysis of shells with large displacements and finite rotations
4. E.I. Bespalova, A.B. Kytaygorodsky: The full systems method in dynamics problems of 3D bodies
5. R. Sieniawska, P. Śniady, S. Żukowski: Sensitivity and analysis of the bar structures reliability
6. M.M. Duras: Continuum field model of street canyon: theoretical description. Part 1
7. M.M. Duras: Continuum field model of street canyon: numerical examples. Part 2

A. Garstecki, W. Kąkol, K. Rzeszut: Analysis of thin-walled bars with open and closed-open cross-sections

The paper presents the numerical analysis of global and local buckling of columns made of steel cold-rolled, very thin-walled cross-sections of sigma (S) and double sigma (2S) type. Variation of the buckling stress for a wide range of slenderness ratio is presented. The deformation of the contour associated with different buckling modes and warping of open and closed-open sections is discussed, too. The exactness and numerical efficiency of different methods are studied on several examples. Finite Element Method incorporating the Vlasov beam element and shell element is compared with the Finite Strip Method.

Contents

R. Korycki: Identification of the material phases location for the one-dimensional unsteady heat conduction problem

The present paper is devoted to identification of the material phases location for one-dimensional structure with respect to the first-order sensitivity of the identification functional. A transient heat conduction problem within a thermal anisotropic one-dimensional structure is formulated. The material derivative concept and both the direct and adjoint approaches are used in considering the shape identification of the problem domain. The identification functional is assumed in the form of the "distance" between the temperature of the identified body and the measured temperature of real structure. Stationarity conditions are formulated with respect to the obtained first-order sensitivities. Numerical examples of internal boundary identification are presented.

Contents

J. Marcinowski: Static and stability analysis of shells with large displacements and finite rotations

The paper deals with large displacements and finite rotations of elastic shells subjected to the action of external loads. The numerical approach to the problem based on the finite element method in displacement formulation is presented. The degenerated finite element originally introduced by Ahmad et al. [1] and subsequently supplemented by Marcinowski [2] was used in this paper. This very element was essentially suitable for shell problems exhibiting small and moderate rotations, but there exists a possibility to apply it also to problems with finite rotations, provided the updated Lagrangian formulation is adopted. Details of such an approach were presented in the paper. Several examples taken from the literature and confirming the correctness of the applied approach were included.

Contents

E.I. Bespalova, A. B. Kytaygorodsky: The full systems method in dynamics problems of 3D bodies

A new method is proposed to solve the problems of stationary dynamics for inhomogeneous anisotropic 3D bodies of finite sizes with arbitrary conditions on bounding surfaces. It is the reduction of the initial three-dimensional boundary problem to the system of three correlated one-dimensional boundary-value problems. Thus the increase of the number of independent variables results in the linear (but not exponential!) increase of the required computer resources. This determines the method efficiency when solving multidimensional problems. Several examples of solution for particular problems of mechanics of deformed bodies are presented.

Contents

R. Sieniawska, P. Śniady, S. Żukowski: Sensitivity and analysis of the bar structures reliability

In the paper certain theoretical basis and practical approach for design sensitivity analysis of bar structure's reliability under a special type of excitation are presented. The analysis is carried out for the plane bar structures made of linearly elastic material. It is assumed that the structure's physical and geometrical parameters are deterministic variables and a non-Gaussian stochastic process describes the load. Examples for a beam loaded by a stream of moving random forces are presented.

Contents

M.M. Duras: Continuum field model of street canyon: theoretical description. Part 1

A general proecological urban road traffic control idea for the street canyon is proposed with emphasis placed on development of advanced continuum field gasdynamical (hydrodynamical) control model of the street canyon. The continuum field model of optimal control of street canyon is studied. The mathematical physics' approach (Eulerian approach) to vehicular movement, to pollutants' emission, and to pollutants' dynamics is used. The rigorous mathematical model is presented, using gasdynamical (hydrodynamical) theory for both air constituents and vehicles, including many types of vehicles and many types of pollutant (exhaust gases) emitted from vehicles. The six optimal control problems are formulated.

Contents

M.M. Duras: Continuum field model of street canyon: numerical examples. Part 2

Continuum field control model of a street canyon is considered. The six separate monocriterial optimal control problems consist of minimization of functionals of the total travel time, of global emissions of pollutants, and of global concentrations of pollutants, both in the studied street canyon, and in its two nearest neighbour substitute canyons, respectively. The six optimization problems for the functionals are solved numerically. General traffic control issues are inferred. The discretization method, comparison with experiment, mathematical issues, and programming issues, are presented.

Contents

Abstracts for 48, 3, 2000 (previous issue)

Abstracts for 49, 1, 2001 (next issue)

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