Evgeny V. Gorokhov, Volodymyr M. Vasylev, Andrii M. Alokhin
Test procedures of aerial supports on the testing ground of Donbas national academy of civil engineering and architecture
Donbas National Academy of Civil Engineering and Architecture
Abstract. The paper has presented the test procedures of aerial supports on the testing ground of tests of overhead power lines and tower structures of the Donbas National Academy of Civil Engineering and Architecture. The following engineering research tasks: determination of the bearing capacity and deformability of the aerial supports under the effect of the glazed ice and wind attacks have been set up. The research object – a tetrahedral narrow-base support AO-60 with the Howe truss consisting of single angles – has been chosen. The aerial support has been the three-dimensional strut truss in the form of a rectilinear tetrahedral pyramid with the upper prism part of 1 m and with the height of 60 m. The detail drawings of the aerial support have been worked out at the Metal Structures Department of the Academy. The technique of test procedures of the aerial supports has been approved. The general scheme of the experimental plant and gauge length to study of the natural glazed ice and wind attacks has been offered. The given technique enables to provide the large-scale tests not only for the aerial supports but also for the power line supports, supportive and distributive devices, tower cranes to check the bearing capacity and deformability with real attached loads.
Keywords: aerial support, testing ground, technique, test, glazed ice and wind attacks, experimental plant, loading scheme, force, load, electrodynamometers.
Mykhaylo I. Kazakevitch
Aeroelastic instability of girder beam bridges
Dnipropetrovsk National University of Railway Transport
Abstract. The paper has cited the analysis of causes of origin of aeroelastic instability of vortex excitation of the multispan girder beam bridge across the Volga in Volgograd, Russia. The forecast of the capable stability ways of the construction in a vortex flow at the first stage of the bridge operation with one stiffening girder has been made. The second phase of bridge construction at the certain terms of merging of two adjacent stiffening girders can considerably improve both bridge aeroelastic stability and its fatigue strength.
Keywords: vortex excitation, aeroelastic instability, fatigue strength.
Viktorija E. Volkova
Criteria for identification of non,linear models of dynamic systems
Dnepropetrovsk National University of the Railway Transport
Abstract. The paper considers the problems of structural identification of the dynamic systems on the basis of the analysis of the phase paths and their reflections in the extended phase space. The analysis of the present techniques of revealing of the non-linear structures of the dynamic model of the mechanical system has been done. On the basis of the analytical study of the phase paths properties, the method of non-linear structure revealing of the system without application of parametric estimation methods has been worked out. The method assumed by the author demonstrates the feasibility of identification of mechanical systems models with application of phase paths reflections on the plane «acceleration — displacement». The offered method is close to the method of the temporary processes treatment, but unlike of the present methods of the qualitative identification, it is not so awkward in application.
Keywords: non-linear dynamic models, phase paths reflections, phase plane «acceleration — displacement», structural identification.
Volodymyr P. Mushchanov, Margarita P. Kashchenko, Yulia V. Syvokon
Determination of «free» length section of shell supporting outline on square layout
Donbas National Academy of Civil Engineering and Architecture
Abstract. The principle problem considered in the paper is imperfection of the determination technique of «free» length of the compressed and curved supporting contour in comparison with the previous known approaches. The outcomes of the design by recommended technique can be furthermore used at estimation of bearing capacity of a element during the design by the first group of the limiting states instead of the existing awkward and inconvenient formulas to determine the critical load in available techniques.
Keywords: shell, compressed and curved contour, stressed and strained state, stability, «free» length.
Evgeny V. Shevtchenko, Volodymyr A. Mitrakov, Anton V. Tanasoglo
Determination of reduced tension at conductor breakage
Donbas National Academy of Civil Engineering and Architecture
Abstract. The purpose of the paper is the development of the numerical and analytical method of problem solution of the conductor tension determination after its breakage. The solution of the problem is realized in programming complex MS «Excel». The section of the overhead power line (OPL) — an anchor site consisting of two anchor supports and suspension supports situated between them with conductors and an overhead ground-wire cable has been taken as the pattern. The supports are considered to be the components of the whole structural system of the electrical network. The conductor breakage is simulated in turn in each of eleven spans. While designing, the value of the reduced tension of conductor has been analyzed. It has been done to determine the load to a suspension support at emergency operation and the value of the conductor sag at a span adjacent to an emergent one. The flexibility of the OPL supports has been given consideration. It was established that flexible supports get out of plumb of the remained conductor because of its tension and to the suspension point displacement after an insulator string deviation there is also the support sag. On the basis of the design and integration of the results, the relationship of the reduced tension value of the amount of the following spans of the anchor section with the remained conductor has been determined. The amount of spans necessary for finding of the maximum reduced tension value has been revealed.
Keywords: overhead power line (OPL), reduced tension, three-dimensional model, OPL support, set system of equations, design loads.
Yaroslav V. Nazim, Volodymyr M. Vasylev, Sergey M. Bakaeyev, Nataliia S. Smirnova, Nataliya V. Agbash
Engineering research of hinges to provide reliability of overhead power lines (OPL)
Donbas National Academy of Civil Engineering and Architecture
Abstract. Abstract. The paper is the logical continuation of the early studies in the field of reliability assurance of overhead power lines located in the southern regions of Ukraine where there are increased glazed ice and wind loads. The paper has given the investigation findings of conductor/clamp systems removed during their replacement on the OPTL 330 kW «Kakhovskaya — Ostrovskaya» and «Kakhovskaya — Dzhankoy» and also of the joint specimens of the arrival for the next suspender. The investigation findings of dismantled specimens have revealed geometric dimensions deviations caused by corrosion and mechanical wear as well as discrepancy between steel components and chemical composition to specified requirements for operation under field conditions. The causes of fault conditions have been established and recommendations directed to the improvement of OPTL operation and energy supply reliability increase have been provided.
Keywords: overhead power lines (OPL), conductor/clamp systems, metallography, microstructure, metal chemical composition, reliability.