Gorokhov Yevgen, Vasylev Volodymyr, Alokhin Andrii
Dynamic behaviour research of AO-60 aerial support on testing ground of Donbas National Academy of Civil Engineering and Architecture
Donbas National Academy of Civil Engineering and Architecture
Abstract. The paper presents the testing technique and the results of the dynamic runs of the aerial support AO-60 under the effect of glazed ice and wind loads. The support vibrations excitation has been made by two methods: by a vibrator with the managed frequency of rotation of the eccentrically fastened load (vibration machines) [7, 11] — to determine the natural frequency of vibrations on the first form and the breakage rope method — to excite the vibrations on the first form [11]. The research of the AO-60 support has been conducted on the Academy testing ground to determine the natural vibrations values of the support and to check the design scheme at the dynamic effect of the glazed ice and wind loads. The dynamic tests have enabled to determine the real natural vibration frequencies of the AO-60 aerial support under the effect of the glazed ice and wind loads and to compare the research and investigations.
Keywords: research, aerial support, testing ground, dynamic tests, glazed ice and wind loads, natural vibration frequencies, resonance.
Denisov Evgeny, Fomenko Serafim
Features of application of rigid bus designs in outdoor switchgears
Donbas National Academy of Civil Engineering and Architecture
Abstract. The paper deals with the domestic and foreign experience of rigid bus design application in outdoor switchgears. There have been various variants of rigid bus design, including the big spans. The principle emphasis in the design analysis has been done to the ways of vibration termination of rigid bus designs at vortex excitation of vibrations under the wind effect. The familiar ways of vibration damping of the rigid bus designs have been analysed. The main principles of work of special-purpose vibration damping devices – dampers used in this kind of designs have been considered. The latest designs and offers of the problems proposed by the Russian and Ukrainian researchers have been also presented in the paper. The disadvantages of the existing methods of vibration termination have been pointed out and the conclusions of the prospect trends of research and investigations in the sphere of generation and invention of fresh methods of vibration termination in the rigid bus designs have been formulated.
Keywords: rigid bus, tube-busbar, outdoor switchgear, damper, damping, wind resonance, vortex vibration excitation.
Zelentsov Dmytro, Radul Oleksandr
The solution of the problem of corroding structures durability under the constraint on the allowable error
SHEE «Ukrainian State University of Chemical Engineering»
Abstract. The solution for the problem of durability of the statically indefinable deca-bar truss operating in the active corrosive medium has been proposed. The general case of corrosion interaction, when speed of corrosion depends on stresses, has been considered. The existing approaches to problem solution and to determination of solution error have been described and their advantages and disadvantages have been pointed out. The expediency of application of the knowledge base about the influence of various factors on the accuracy of the numerical solution of durability of corroding structures to determine the integration step of the system of differential equations, describing the process of corrosion ware, has been substantiated. The possibility of artificial neural networks application in order to ensure a specified accuracy of the calculation of truss’s durability, while minimizing the number of calls to the procedure of the finite element method, has been studied. The series of artificial neural networks with the direct signal propagation and one hidden layer have been used. The numerical illustration of the proposed approach has been cited.
Keywords: structural mechanics, statically indefinable truss, corrosive wear, durability, method of finite elements, integration step, allowable error, artificial neural network, knowledge base.
Mushchanov Volodymyr, Zubenko Ganna, Vardanyan Arusyak
Impact of membrane roof on stressed and strained state of vertical tubular tank wall
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article contains the statement of the problem and analysis and design techniques of the vertical tubular tanks (VTT) with sagging membrane roofs at the stressed and strained state parameters determination with regard to the joint behaviour of the VTT wall and roof support outline. Methods of the problem solution have been reviewed. The analytical and numerical investigation confirming the effect of the VTT wall on the principle indices of the stressed and strained state and engineering and economic figures of the sagging roof at various stabilization ways has been conducted by the example of vertical tubular tank by volume of 20 000 m3 with the height of the walls of 12 and 18 m.
Keywords: vertical tubular tank, membrane roof, stressed and strained state, roof stabilization.
Yugov Anatoly, Bondarev Oleksiy
Stressed and strained state of flat frame members investigation with regard to geometric imperfections
Donbas National Academy of Civil Engineering and Architecture
Abstract. The paper deals with the problem of impact of indices of manufacturing accuracy and erection of U-shaped frame metal structures to the parameters of the stressed and strained state. The analysis of the U-shaped flat metal frame with regard to its manufacturing defects has been made. The design-basis values of forces in the U-shaped frame members at length deviation of the frame members from their nominal one have been analyzed. The values obtained at design indicate the necessity to provide the defects at determination of the actual stressed and strained state of bar metal structures. The method enabling to simulate the length deviation of a member from the nominal one during the static analysis has been cited. The recommendations on application of this method at the design work of metal structures have been given. The design technique cited in the paper can be used at the design work of bar structures.
Keywords: metal structures, stressed and strained state, manufacturing defects, erection, MFE, accuracy.