Anatoliy Yugov, Alexey Bondarev
Assembly efforts in wide-span spatial rod system determining technique
Donbas National Academy of Civil Engineering and Architecture
Abstract.The paper proposed a technique of determining of the assembly effort to wide-span system with the sequence of erection. Control-flow chart of technique of determining of the assembly efforts based on computational analysis of complex dimensional bar structures has been given. The proposed technique of estimating of the stress-strain state of the rod system with the installation of impacts, assembly forces may be used in the process of real designing. The general form of designed objects can be varied: cylindrical, spherical, elliptical, toroidal, conical and the other. Best technique can be applied to predict the spatial assembly efforts of span of coatings, lattice towers, power transmission line support and others which are in the form of rod systems (usually of metal), both in their design and evaluation of already exploited.
Keywords: spatial-span metal systems, assembly errors, mounting stress, dimensional chain, stress-strain state, FEM.
Volodymyr Kushchenko, Alexandr Nechitaylo
Experimental research of the mode of deformation of sub-pulley structures of shaft frame-type sloping headgear
Donbas National Academy of Civil Engineering and Architecture
Abstract.The paper is about the theoretical and experimental survey of the mode of deformation of the guide pulley resting joint of the shaft frame-type sloping headgears. As a result of the mathematical modeling and statistical analysis of the experimental data we have ascertained the mechanism of local stress distribution; the characteristics of the dynamic stresses for testing the sub-pulley structure fatigue stress. We have compared the results of the mathematical modeling and physical experiments and have estimated the resource of the sub-pulley resting joints by fatigue stress. By and large the obtained data provide a basis for the improvement of the engineering procedures of designing steel structures of shaft sloping headgears.
Keywords: shaft sloping headgear, sub-pulley structures, guide pulley resting joint, stressed state, local stresses.
Ivan Peleshko, Volodymyr Ivaneiko
On one way of specifying topology variants of steel bar structures for structural and parametric optimization problems
National University «Lviv Politechnique»
Abstract.The article suggests a method of specifying a set of variants of bar structures for structural and parametric optimization problems of geometry, cross sections of bars and structure topology. The method includes formation of tuples of nodes for describing set of topology variants of bar system and using of discrete design variables to select specific topology variants during the optimization process. In this case topology variants can be formed with different number of nodes and bars and on the stage of the data input of optimization problem. The structural and parametric optimization problem is formulated for eaves truss. The article gives the instance of the specifying of tuples with the nodes for eaves truss. It is described the implementation of the proposed method in program for optimal design of steel structures OptCAD. Structure optimization problem is solved by harmony search method.
Keywords: bar structures, steel structures, topology optimization, discrete design variables.
Vadim Gubanov, Artem Kulchytskyy, Olexandr Golikov
Justification of experimental research of influence of local dimple on the stress-strain state of metal chimneys shells
Donbas National Academy of Civil Engineering and Architecture
Abstract.The results of field surveys of metal chimneys are presented in the article. The basic geometric imperfections metal chimney’s shells are revealed. Systematization of the data of geometric imperfections is performed and their frequency is determined. For the laboratory research on determining effects of the local dimple on the stress-strain state of metal chimney’s shells the equivalent wind load was identified and substantiated. A laboratory setting for studying the influence of local dimple on the stress-stain state of shells metal chimneys were designed and manufactured on the basis of numerical studies. The sequence of a laboratory experiment is determined.
Keywords: steel chimney, geometrical imperfections, equivalent, local stresses, scale model, the stress concentration.
Volodymyr Mushchanov, Ganna Zubenko, Ivan Moskalenko
Numerical simulation of wind pressure on a vertical cylindrical tank surface
Donbas National Academy of Civil Engineering and Architecture
Abstract.When designing buildings and structures one of the main existing loads is the wind. A particularly large impact it has for vertical cylindrical tanks (VCT) in the calculation of its members on sustainability. This article examines the comparative analysis of aerodynamic characteristics of the model VCT, and forecasting on the basis of the received results of aerodynamic characteristics for group VCT method of numerical modeling in complex software Solid Works Flow Simulations, also suggests a methodological approach which ensures the correct display of physical processes of the flow of the wind flow vessel wall. For the group of 4 tanks on the basis of numerical simulation, the specified values of aerodynamic coefficients of wind pressure for each group of tanks providing further refined assessment of stress-mode of construction of the wall in comparison with regulated in the present approach, DBN and Euro codes have been carried out.
Keywords: vertical cylindrical tank, numerical simulation, wind pressure, aerodynamic coefficient.
Olena Voskobiinyk
Comprehensive methods of risks management during exploitation of buildings and structures
Poltava National Technical University named after Yuri Kondratyuk
Abstract.The article is devoted to development of comprehensive methods of risk management during exploitation of buildings and structures. The social, economic and technical aspects of risks management were considered, the overall structure of the technical risks of construction projects for the type of potential social and economic losses due to failure (failure) were done. Mathematical models and criteria of differentiation of the technical states offer taking into account the risk of incorrect diagnostics at an inspection and technical diagnostics of building constructions, building and structures are proposed. Optimization approaches are considered in relation to minimization of function of middle risk of incorrect diagnostics. The proposed device can be used by engineers, designers and specialized organizations which are dealing with the technical diagnostics of constructions, and also specialists-actuaries for the actuarial calculation of insurance risk when insuring real estate objects taking into account their actual technical condition.
Keywords: exploitation, technical condition, reliability, technical diagnostics, technical risks management, risk of incorrect diagnostics.