Ye.V. Gorohov, V.F. Mushchanov, Yu.V. Sivokon, R.I. Kinash, A.Ye. Kopylov
Experimental studies of a stadium coverage form influence on aerodynamic loads
Donbas National Academy of Civil Engineering and Architecture;is Institute of a build technique
Abstract. There are described the methods of conducting experimental aerodynamic researches of the model of a coverage convex and concave shell with a large cutout on an elliptic plan. The coverage (columns) vertical bearing structures were made in 2 variants: either without an enclosure or with an enclosure. The main purpose of testing the coverage model in a wind channel is to increase knowledge about a wind load influence on the structure under study, the values of the aerodynamic coefficients obtained being used when designing membrane coverings above stadium stands. Similar researches were repeatedly conducted by scientists in many countries. To carry out the tests the models of coverage were made on a scale 1:500. There are described the models of covering a stadium, the analysis of experimental researches for convex and concave shells has been done. There are given the plots of pressure coefficient changing on a shell lower and upper face.
Keywords: experimental aerodynamic researches, a coverage shell model, methods of aerodynamic testing, coefficient of pressure.
V.O. Popov
Analytical and numerical simulation of a deflected mode of high pressure gasholder for an intelligent design
Vinnitsa National Technical University
Abstract. There are examined analytical and numerical simulation of a high-pressure gasholder deflected mode of low-alloyed steel using the up-to-date programs Lira 9.4 and Cosmos-Works. Using the methods of structural mechanics and theory of strength of materials, the gasholder most rational structural form and geometrical parameters were revealed. Numerical results obtained by the programs Lira 9.4 and Cosmos-Works were compared to fix their reliability. It has been proved that the models created by the both programs give conservative values of the equivalent stresses in comparison with an analytical model. Numerical results obtained with the help of Cosmos-Works have four-time as little the relative error than the results obtained with the help of Lira 9.4 in comparison with the results of the numerical simulation, and thus are more reliable.
Keywords: high pressure gasholder, deflected mode, equivalent stresses, rational design, thick-walled steel casing. of pressure.
A.M. Alyokhin
Influence of scale factors Kv, Kв, Кф and Kн on the imitation of rime in the DonNACEA climatic chamber
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article is about the systems of basic correlations containing eight scaling factots to imitate rime in the DonNACEA climatic chamber. The factors presented characterize the conditions of similarity and dependence between the parameters of the field and model processes of cloud drops precipitating from the air stream on similar and natural bodies, and icing on them. The first two equations (1) and (2) of the system are analysed. The KV factor indicates a connection between air streams in the DonNACEA climatic chamber and on a field object model object, and the Kv factor carries the information about the size of the object under testing and a field one. Their relation determines the coefficient of the relations of temporal segments of icing. There are obtained dependences between the KV, КV, Kв, Кф and Kн factors . When carrying out the experiment in the climatic chamber it is necessary to get such less values of Kv and KV, so they are to be Kv<1 and KV<1.
Keywords: scale factors, system of equations, the DonNACEA climatic chamber, experiment, nature, model, rime, air stream, the system of co-ordinates, hyperbola, straight line, curve, Taylor series.
A.M. Yugov
Estimation of building metal structures imperfections on the basis of the fuzzy-set theory
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article is devoted to the estimation of building metal structures imperfections. A structure gets imperfections in the processes of manufacture, transportation, erection and operation. The basic condition of guaranteeing the trouble-free operation of metal buildings and structures is diagnostics of technical conditions as a whole and available defects and damages in particular. The data about imperfections are obtained when inspecting buildings and structures. There is put forward the mechanism of estimating imperfections at their continuous accumulation. Estimation of technical conditions is based on the results of the primary expert judgement. There is suggested and substantiated a mathematical model of cumulative accumulation of imperfections on the basis of the fuzzy logic apparatus. Analysis of a constructive risk for each element is reduced to the comparison of design, valid and limiting values of the determining parameters. The apparatus offered allows estimating reliability of metal buildings and structures under operation.
Keywords: building metal structures, imperfections, reliability, fuzzy logic, constructive risk.
V.M. Kuschenko, O.V. Mykhailov
Specification of emergency loads structure of head-frames
The Donbas National Academy of Civil Engineering and Architecture
Abstract.
On the basis of generalization of the results of mathematical modeling of the dynamic behaviour of the mechanical system «head-frame structures – a winder» a specification of special loads structure has been done. For head-frames structures equipped with winders which have technical characteristics causing a possibility of a hoisting rope breaking on jamming a rising vessel, design values of special loads being determined by a maximum value of the amplitude of a total hoisting rope tension which is determined by a critical value of the length of the hoisting rope jammed branch at a given speed of a winder movement. For the structures of cage winding head-frames, at a hoisting rope breaking as a result of jamming a rising vessel, the effort in an adjacent branch can keep on increasing and reach a peak value at the moment of a dog response. As a result of this when determining a special load because of a dog response, besides the efforts in brake ropes one should take into account a peak value of the effort in a hoisting rope adjacent branch. For the structures of skip hoisting and cage winding head-frames which are not equipped with a dog and for which a hoisting rope breaking it is not possible, one should consider a possibility of breaking a hoisting rope as a result of a rising vessel hanging-up at the level of discharges.
Keywords: head-frame, emergency loads, building structure designs.