Publications by authors named "Jozef Bocko"

Isogeometric analysis (IGA) represents a relatively new method of problem-solving in engineering practice. A huge advantage of this method over the finite element method (FEM), is the reduction of the simulation execution time. Non-uniform rational B-splines (NURBS) allow the use of higher-order basis functions, thus increasing the accuracy of the solution.

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The present paper discusses a new approach for the experimental determination of modal parameters (resonant frequencies, modal shapes and damping coefficients) based on measured displacement values, using the non-contact optical method of digital image correlation (DIC). The output is a newly developed application module that, based on a three-dimensional displacement matrix from the experimental measurement results, can construct a frequency response function (FRF) for the purpose of experimental and operational modal analysis. From this frequency response function, the modal parameters of interest are able to be determined.

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The aim of the scientific contribution is to point out the possibility of applicability of cylindrical shells with a constant elliptical cross-sectional shape for stability loss analysis. The solution to the problem consists of two approaches. The first approach is the experimental measurement of critical force levels, where the work also describes the method of production of the sample and jigs that cause the desired elliptical shape.

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Genetic algorithms are a robust method for a solution of wide variety optimization problems. It explores a big space of design variables in order to find the best solution. From the point of view of a user, the algorithm requires the encoding of design variables into the form of strings and the procedure of optimization uses them for optimization.

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In exact analyses of bodies in the elastic-plastic regime, the behavior of the material above critical stress values plays a key role. In addition, under cyclic stress, important phenomena to be taken into account are the various types of hardening and the design of the material or structure. In this process, it is important to define several groups of characteristics.

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Technological units of water reservoirs and power plants include sluice gates which are designed to completely seal the inflow or outflow of water in supply or discharge channels. This article describes the issue of technical assessment of a sluice gate made in the 1950s. Such structures are characterised by states of significant corrosive wear, permanent deformations of contact and sealing surfaces as well as increased levels of residual stresses.

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In recent years, the number of cervical interventions has increased. The stress shielding effect is a serious complication in cervical spine interventions. Topological optimization is based on finite element method structural analysis and numerical simulations.

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This paper deals with the visualization and analysis of interaction of a cutting wedge disintegrator with plastic at low loads. For exploratory research, a contactless optical holographic interferometry method was used, allowing a comprehensive picture of the stress state when opening microcracks. An experimental model was set up for the purposes of the research.

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The calcifying fibrous tumor is a rare benign fibrous tumor which occurs in subcutaneous or deep soft tissues in children and young adults, but also is frequently seen in pleural and intraabdominal locations in older people. Gastric involvement has been only sporadically reported in the literature. We present here our experience with this unusual lesion discovered in a 68-year-old woman.

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Background: The postoperative biological behavior of nonfunctioning pituitary adenomas (NFPAs) is variable. Some residual NFPAs are stable long-term, others grow, and some recur despite complete removal. The usual histological markers of tumor aggressiveness are often similar between recurring, regrowing, and stable tumors, and therefore are not reliable as prognostic parameters.

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