V.N. Кushenko
Methods of Analytical Description of Particular Loads of Slope Head Frames against Technical Characteristics of Mining Hoisting Plants
Donbas National Academy of Civil Engineering and Architecture
Abstract. There are given methods of analytical description of particular loads of slope mining head frames against a rising vessel restraint based on determining the maximum amplitude of a total effort of stretching a hoisting rope strands against the length of a strand restrained, a hoisting height, a hoisting plant masses given, a hoisting rope diameter and strength, a hoist engine rated speed and motion tachogram. There are obtained the formulae to determine dynamic components of efforts in restrained and adjacent strands of a hoisting rope. The designed efforts in a hoisting rope strands are specified as a sum of dynamic and static efforts. If a hoisting engine technical characteristics do not make a hoisting rope breaking possible, an effort dynamic component in a restrained strand is to be multiplied by a dynamic magnification factor equal to 1.5. The methods of analytical description of particular loads of slope mining head frames given in the article have a specifying character with respect to the operational normative methods, this allows rising reliability of the head frame structure design.
Keywords: slope head frames, particular loads, analytical description, design efforts in hoisting ropes.
A.V. Atamanchuck, I.S. Kholopov, D.D. Chernyshev
Wind loads on the trihedral tower elements and ventilation pipe packages
Samara State Architectural and Building University
Abstract. There are given the results of determining wind loads on tower structures including a package of three ventilation pipes and on the structures in the form of a three-pipe package. There was done an experiment in a wind tunnel of a closed type with the open working section above the three-pipe package model. An influence of a wind flow on the thee-pipe package was studied with the help of the FEM. There are presented the pictures of flow past a three-pipe package surface at different angles of a wind flow attack. The shape factor was calculated for a thee-pipe package, a rigging influence and different distances between pipes being included. A qualitative analysis of the stress-deformed state of stack elements was performed. An engineering procedure of specifying a wind load on a trihedral tower structure carrying a tree-pipe package is put forward.
Keywords: pipe package, shape factor, stack.
A.V.Makovetsky
Collapse of Metalwork of the Axisymmetric Shell Type
The Donbass state machine-building academy
Abstract. A research problem of the local collapse of the shell of a complex form is considered in the article. The method of final elements is used to analyze critical pressures. Elements with different geometrical parameters, including the wall thickness, were therewith taken as the model. There are considered the cases of axial and radial compression of a billet. The collapse character at axial and radial loading has been found out. The results obtained have been compared with the analytical ones for different cases of loading. There are given the results of experimental studies of collapse of restrained specially prepared pipes at a axial compression by a male die that made it possible to diagnose the collapse form. The experimental results are compare3d not only with the analytical ones but also with those obtained by FEM modeling at a billet axial loading. Comparison of the equivalent critical stresses shows that the analytical method gives higher values of critical stresses, and the finite-element method gives lower ones. The use of analytical forms for short shells turns out to be unpractical.
Keywords: shell, stability, collapse, load, stress, strain, finite-element method.
S.V. Turbin
Perfecting the Methods of Determining Climatic Loads on Overhead Transmission Lines Adjusted for Local Topographic Peculiarities
Donbas National Academy of Civil Engineering and Architecture
Abstract. The article is devoted to the principles of designing the normative document of the Ministry of Fuel and Energy of Ukraine “Climatic Loads on Overhead Transmission Power Lines Adjusted for Topographical Peculiarities. Determination Methods”. This normative document comprises the basic principles of determining the influence of topographic peculiarities on icing-wind loads, as described in the document mentioned. The normative document also takes onto account the experience of the International working group WG16 “Meteorology for Overhead Power Lines” of the Committee B2 “Overhead Lines” of the SIGRE (an International Council on Large Electric Systems), namely the normative document “Guidelines for Evaluating Special Topographical Effects in Determining Wind Speed for Design of Overhead Lines in Local Terrain”. The international norms and codes, such as Eurocode, the normative documents of the USA , Canada , Japan , Norway , Australia , as well as the principles taken as the principle for new Ukrainian Building codes “Loads and Influences”.
Keywords: overhead power lines, climatic loads, norms and codes, topographical effects.
V.V. Stoyanov
Metallic Reservoirs – Some Problems of Design and Redesign
Odessa State Academy of Civil Engineering and Architecture
Abstract. There are considered the actual for all types of metallic reservoirs problems of decreasing a probability of cracking, and are determined long-term directions of designing reservoirs of 100 thousand and more cubes in volume. The known solutions on cracking under a cyclic loading having been analyzed, there were developed some techniques of cracking slowing-down by using high-0strength and hign-modulus materials of carbon-filled plastic. To exclude additional places of stress concentrates, thin surrounding belts of carbon-filled plastics or other high-strength polymers (instead of massive metallic ring stiffening ribs) are recommended for installation. For reservoir coating, there is recommended a combined structure with a controllable carrying capacity that allows to decrease a specific consumption of materials for roofs more than twofold in comparison with the pontoons that are in use now. The combined structure of coating consists of a system of two-belt lens-shape systems with pneumatic-framework carrying elements placed between filaments and distance bars.
Keywords: metallic reservoirs, cracks, carbon-filled plastic, two-belt lens-shape systems, a controllable carrying capacity.
V.F. Mushchanov, I.V. Romensky, D.I. Romensky
Problems of perfecting two-walled tank designing
Donbas National Academy of Civil Engineering and Architecture
Abstract. The paper deals with the basic questions of increasing the reliability and ecological safety of vertical cylindrical tanks. One of the ways of decreasing a risk is an application of two-walled tanks. A critical unit of such tanks is the one of linking walls and the bottom. A stress-deformed state of such units is influenced by a number of factors. The most important factors are geometrical parameters, constructive solutions, interaction with the bottom, non-uniformity of settling. Among the peculiarities of a chime unit operation we should mention the influence of different loads, namely, static, dynamic, cyclic ones corresponding to normal and emergency modes of operation. There are considered the methods of designing chime units. A numerical model of a chime unit is given in the form of volumetric final elements with a detailed layer-wise layout of walls and bottom fringes. There are considered two variants of constructive decisions, first, every walls rests on its own bottom; second, walls rest on a single sheet. Liquid pressure load is taken as corresponding to normal and emergency operation when the liquid pours out between the walls. The effort values have been obtained, a cross-effect of the walls and the bottom has been analyzed.
Keywords: two-walled tank, problems of designing, a fringe effect, a chime unit, analytical and numerical methods of design.