Applied Engineering Letters

40-45

Authors: S.Franjić

The ultimate and main goal of countries in transition is the integration into the European Union and the integration of energy systems is a natural process. The first step is the restructuring of energy systems at the national level, by separating generation, transmission, distribution and supply, followed by the gradual introduction of market rules. After that, the goal is the integration of national energy in continental, first at the regional level. The Republic of Croatia has accepted all the energy requirements of the European Union and implemented them in practice, and the same is expected from the other candidate countries for membership. The energy sector is one of the most important parts of the national economy.

51-56

Authors: M.Neda, J.Waters

Numerical continuous finite element computations of a fluid flow modelling based on ensemble technique are presented herein. This ensemble algorithm is based on time relaxation. At each time step, it requires the storage of a single coefficient matrix with multiple right‐hands sides which corresponds to each ensemble member. Finite element convergence results for the time relaxation ensemble algorithm are presented and tested in a numerical experiment. This numerical experiment supports the theoretical finite element results. The time relaxation efficiency was shown in the second cavity benchmark problem.

8-15

Authors: A.Asonja; E. Desnica; E. Palinkas;

By using the method of finite elements and starting with the possibilities given by the program system ANSYS in the field of application, research has been performed regarding the analysis of static behavior of a centrifugal pump shaft. The computational analysis of static behavior of shaft using the method of finite elements on the examined model during the phase of projecting, was aiming for a timely sighting of critical spots, in order to avoid possible further malfunction. In this way it is possible to examine validity of the basic solution with no need for making the prototypes. By static behavior analysis, in other words, using the method of finite elements it was shown to which extent can certain conditions of exploitation, created tensions, that is shifted knots, cause difficulties in the whole model performance. Analysis of the static behavior of shaft was performed for two cases with different load: the effect of radial force and the torsion moment. A special attention was given to modelling of rolling-element bearings and following of their condition in relation to outside influences.

24-28

Authors: I. Miletić; M. Miletić;

The paper analyses the stability of a rectangular plate which is elastically buckled along longitudinal edges and pressed by equally distributed forces. A general case is analyzed – different stiffness elastic clamping and then special simpler cases are considered. Energy method is used in order to determine critical stress. Deflection function is introduced in a convenient way so that it reflects the actual state of the plate deformation in the best manner. In this way, critical stress is determined in analytic form suitable for analysis. With help of the equation it is easy to conclude how certain parameters influence the value of critical stress. The paper indicates how the obtained solution could be utilized for determining local buckling critical stress in considerably more complex systems – pressed thin-walled beams of an arbitrary length.