Browsing by Author "Savula, Stepan"

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Access status: Open Access ,
Finite-element analysis of the tubing thread
(2006) Kopey, Bohdan; Kopey, Vladymyr; Bednarz, Stanisław; Savula, Stepan
Cycles of underground gas storage filling and unfilling imply axial loading and internal pressure to tubing thread with dynamic loading in the dangerous planes. The stress - deformation state of coupling with three levels of axial elongation resulted of screwing and external tension loading is presented. The amplitude - frequency descriptions of coupling and tubing screwed together are reached by the harmonic analysis of contact pressure vibrations. The action of vibrations can result in big reduction of contact stresses in tubing coupling thread connection. The computer finite-element axissymmetrical model of the tubing couplings has been developed. The first proper charge frequency is the most dangerous from point of view fatigue destruction of coupling in the critical plane of coupling (the first working pitch thread of pin and the last working pitch thread of box). The most dangerous frequencies of such coupling are the first and third proper charge frequency. Screwing together coupling results in smoothing amplitudes of contact pressure on the working sides of threads.
Access status: Open Access ,
Monitoring methods of technical state of oil and gas pipelines
(2006) Savula, Stepan; Banahevič, Ûrij; Dragilev, Andriej; Kičma, Andriej
A method of assessing the state of stresses in welded joints of pipelines with the use of numerical-experimental diagnostics is presented in the paper. Recommendations for engineers are formulated on the basis of the experimental results.
Access status: Open Access ,
Tłumienie drgań kolumny rur pompowo-sprężarkowych w odwiercie podziemnego zbiornika gazu
(2006) Savula, Stepan; Harčenko, Ïvgen
While pumping gas from the main pipeline into the gas storage and vice versa, turbulent processes appear in the well that quite often results in considerable vibrations of the lover part of the column of the tubing string. Because of this, the column screw thread halving is weakened, lower pipes sometimes unscrew and fall into the well. It substantially violates the normal operating mode of the gas storage and negatively affects its productivity. If the lower end of the column is not fastened then it takes the dominant role in the vibration processes. Fixing the lower part of the column by means of spacing devices substantially enables decreasing the amplitude of the tubing string and improving the conditions of the screw thread halving.