Abstract.A procedure for the numerical analysis of the dynamic response during the passage of railway vehicles is described. The solution is based on the finite element method (FEM), which is used for the calculation of track stresses. An FEM model was used with a fine structure that included all components of switches and crossings, including movable parts. The excitation forces are defined on the basis of the assumed interaction between track and vehicle. The track stiffness defined by FEM analyses is used for the calculation of dynamic vertical and lateral wheel load. A special model of a railway vehicle was built with the aim of calculating the forces at points where abrupt stiffness changes occur, as well as geometrical imperfections in the frog structure.

The paper deals with the numerical analysis of forced vibrations of a slender water tower structure. The computation model has been developed using finite elements in the ANSYS program environment. For CFD (Computational Fluid Dynamics) analysis the CFX module was used. The computation model includes the precisely modeled thin-walled steel structure and two variants of fluid domain. Elements FLUID30 formulated for direct description of the fluid pressure field has been applied and Lagrange description FLUID80. The Raleigh’s model of energy dissipation has been used. Similarity of normal modes of vibration has been applied as the criterion for defining the relations between computed natural frequencies of the empty tank and filled with water. To obtain accurate wind induced forces the CFD model of air surrounding was modeled. From this model the relation between velocity of unaffected stream and vortex separation frequency. Forced vibrations of the tower excited by vortex shedding harmonic pulsations have been computed.

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The paper deals with the seismic analysis of safety related structures of an operating nuclear power plant. At present time the nuclear power plants of VVER-400/213 type operate for over thirty years and there are arising requirements to verify the actual state of structures in order to assess their residual life in general. A sophisticated computation model has been developed for the seismic structural analysis using the ANSYS program package. The model involves the complex of all constrained structures of two main production blocks with equipment. In order to get a general view at the seismic load effects, seismic response analysis has been performed using direct integration of equations of motion in 25 sec interval at 0.01 sec step with excitation described by accelerograms. Combinations of dead loads and seismic loads have been considered in the stress assessment of the structures. The results of the performed analyses form a base for residual life prediction of selected structures

Abstract. The load-bearing structures of footbridges are designed to be slender and feature spans of considerable length. It can be expected that the natural frequencies of such load-bearing structures range from 0.5 Hz to 5.0 Hz. These low natural frequencies are problematic as regards the effects caused by the dynamic component of wind or the movement of persons. Increased acceleration values can lead to the serviceability limit state of structures being exceeded or the heightening of stress which can result in damage to the structure mainly in the area of details prone to fatigue. The contribution deals with the requirements concerning the execution of dynamic analyses which are listed in the relevant technical standards. It will present procedures for the determination of dynamic loading, methods of solving dynamic tasks as well as design criteria enabling delicate bridge structures to be designed correctly.