English English

Archives

THE ALGORITHM OF COMPLEX DIAGNOSTICS OF TECHNICAL CONDITION OF BUILDING STRUCTURES ON THERMOGRAMS ANALYSIS

https://doi.org/10.34031/2618-7183-2019-2-2-23-28
 23-28 p.
Abstract
The algorithm of complex diagnostics of a technical condition of building constructions and structures on the analysis of thermograms is offered. An attempt is made to systematize and logically build a sequence of stages of energy inspection of heat-consuming and heat-generating construction projects and their structural elements. The presented algorithm includes the main stages performed in such surveys. It differs from the known technologies of energy monitoring of buildings and structures by the presence of two additional stages, which are an integral part of any energy survey: determination of the relative surface humidity of building structures and the actual mass flow of coolant through the heating device for the analysis of thermal images. The implementation of energy (thermal imaging) and technical inspections according to the presented structural scheme requires not only the presence of appropriate instrumentation and measurement base, but also the involvement of highly qualified specialists (civil engineers, thermal power engineers, thermal physicists, operators-thermographers, etc.).
PDF

CALCULATION OF THE SLEEVE PACKER ELEMENT WITH THE VARIABLE ANGLE OF LAYING OF THREADS OF THE CORD FOR CREATION OF EDGE PROTECTION (PART 1)

https://doi.org/10.34031/2618-7183-2019-2-2-29-40
, , ,
 29-40 p.
Abstract
The method of calculation of influence of design and technological parameters of material of a cover of a packer element is developed: the initial angle of laying of threads of the reinforcing framework, the packing density of threads in the field of unions, number of layers of a framework, rubber elastic modulus on power characteristics of a cover, for the purpose of creation of edge protection of a packer element. In the first part of work the cover of a packer element with laying of threads with a constant corner on all length of a cover is investigated. The received results of calculation, allowed to evaluate and prove quantitatively the constructive and technological directions of reliability augmentation of edge protection of a packer element. The developed calculation procedure is a basis of development of more general method of calculation of power characteristics of a cover of a packer element with variable longwise covers the initial angle of laying of threads.
PDF

CALCULATION OF THE SLEEVE PACKER ELEMENT WITH THE VARIABLE ANGLE OF LAYING OF THREADS OF THE CORD FOR CREATION OF EDGE PROTECTION (PART 2)

https://doi.org/10.34031/2618-7183-2019-2-2-41-49
, , ,
 41-49 p.
Abstract
In the presented part of work the case with the angle of laying variable longwise of the reinforcing threads of a packer element in median and edge zones is investigated. Calculation of power characteristics of a cover of a packer element with various slopes is carried out. Tests of natural prototypes of covers the packer ele-ments are carried out. The calculation results compared with data of an experiment are presented in the form of schedules with good degree of convergence. The developed technique allows to choose an optimum design of covers of a packer element with higher value of rigidity on face sites that ensures reliable functioning of a packer element at pressure differences in annular space.
PDF

A BLOCK OF THERMAL INSULATION MATERIALS WITH PROTECTIVE AND DECORATIVE COATINGS

https://doi.org/10.34031/2618-7183-2019-2-1-4-10
, , , ,
 4-10 p.
Abstract
Scientific and technological principles of alternative plasma technology for the production of two-layer heat-resistant glass-like decorative coating were developed. The compositions of the intermediate heat-resistant layer and the technology of its application to the surface of the enclosing block of foam glass are proposed. The optimal parameters of plasma melting of heat-resistant and decorative coating layers were determined. The influence of high-speed characteristics of plasma jet thermal melting on the formation of texture and performance of two-layer heat-resistant coating is established. The features of the formation of amorphous vitreous and glass-crystalline phases of a two-layer heat-resistant coating are presented. Using x-ray phase analysis, the features of the phase composition of different layers of heat-resistant coating, as well as the laws of formation of its structural elements are studied. Based on the analysis of significant experimental material, it was concluded that the formation of the upper amorphous layer with liquating regions and minor gas inclusions. The conducted researches allowed to reveal and justify the features of the structure of the layers lying under the amorphous liquating. It was found that the two-layer protective and decorative coating had high physico-chemical and physico-mechanical properties: adhesion strength to the matrix of the foam glass block-1.25 ± 0.05 MPa, microhardness-785 HV, heat resistance-122°C, acid resistance – 98.5%, alkali resistance – 95.4%.
PDF

SHEET BUILDING GLASS WITH PROTECTIVE AND DECORATIVE COATINGS

https://doi.org/10.34031/2618-7183-2019-2-1-11-16
, , , ,
 11-16 p.
Abstract
Sheet glass with decorative coatings in industrial and civil construction play an important role in improving the aesthetic properties of buildings for various purposes. An innovative technology for obtaining decorative coatings on sheet glasses using low-temperature plasma is proposed. For plasma spraying crushed in a ball mill container glass of various colors was used. The optimal parameters of the plasma spraying of glass powders on the front surface of the glass sheets were established. To increase the adhesion strength of the coating to the substrate before plasma spraying, the front surface was heat treated with outgoing plasma-forming gases. It was found that with increasing temperature of the outgoing plasma-forming gases and the time of their impact on the front surface of the sheet glass, the adhesion strength of the coating with the base increases to 6.7 MPa. The effect of the coating thickness on the strength of its adhesion to the substrate is studied. Increasing the coating thickness from 150 to 1000 µm reduces the adhesion strength from 7.5 to 3.2 MPa. Under the influence of high temperatures of arc plasma is not only an increase in the glass refractory oxides of silicon and aluminum, but also an increase in their hardness up to 15%.
PDF

ANALYSIS OF THE INFLUENCE OF THE QUALITATIVE COMPOSITION OF THE ASPHALT-CONCRETE MIXTURE ON THE MAIN PERFORMANCE CHARACTERISTICS OF ASPHALTIC CONCRETE PAVEMENT

https://doi.org/10.34031/2618-7183-2019-2-1-17-23
 17-23 p.
Abstract
The paper presents an analysis of information quality assurance of production of asphalt concrete mixtures, as well as the study of the relationship of the qualitative composition of asphalt concrete mixtures and physical and mechanical characteristics of asphalt concrete pavement. The study of the main characteristics was carried out on the example of asphalt concrete type B and grade I and crushed-mastic asphalt concrete – SchMA-20. It is established that the deviation of asphalt mixtures in composition from the required values leads to their under-compaction in the pavement. It is also established that increasing the number of inconsistencies in the asphalt concrete mixture leads to an increase of physical-mechanical characteristics that differ from the requirements of GOST 9128-2013 and GOST 31015-2002 respectively. As an information base for the assessment of the influence of granulometry of the mineral part of asphalt concrete, as well as the amount of bitumen on the main characteristics of asphalt concrete, the data of the current ACP of Belgorod region were used. Analysis of the particle size distribution was carried out using a laser analyzer of asphalt ABA7/35B. The obtained data became the basis for a further study of the influence of various parameters on the properties of asphalt mixes, as well as improving the efficiency of the asphalt mix production management system.
PDF

ANALYSIS OF THE FACTORS INFLUENCING THE CHOICE OF INSULATION SYSTEMS OF EDUCATIONAL INSTITUTIONS

https://doi.org/10.34031/2618-7183-2019-2-1-24-31
,
 24-31 p.
Abstract
The article raises the problem of improving the energy efficiency of buildings in operation with a constant increase in energy prices, which is now becoming increasingly important. The analysis of the design deci-sions of the buildings of educational institutions of Donetsk region was carried out; the main typical series of the region were highlighted and given. The issues and the factors affecting the heat and moisture characteristics of enclosing structures of educational institutions were discussed. The values of resistance to heat transfer for the most common standard series of secondary schools are given. The modeling of temperature fields of nodes of public buildings of standard series was made. The most unfavorable design solutions of serial buildings were identified by the following factors: the temperature of the inner surface of the outer enclosures and the temperature difference between the average temperature at the surface and the air temperature in the room. Possible ways of thermo-modernization of such buildings with consideration of the requirements for temperature and breathability are considered. The influence of heat-conducting inclusions on the heat-moisture regime of external enclosing structures during partial and full thermal modernization is estimated. The analysis of various methods and ways of warming the buildings of educational institutions are performed. The advantages and disadvantages of the proposed options from an economic point of view are indicated, as well as on the basis of the requirements of fire regulations.
PDF

INVESTIGATION OF THE STRESS CONDITION OF RIVETED JOINTS BY FINITE ELEMENT METHOD

https://doi.org/10.34031/2618-7183-2019-2-1-32-36
, ,
 32-36 p.
Abstract
Traditional methods of calculation of rivet joints are based on very approximate methods of determining the forces arising in the connection. This leads to serious inaccuracies in the determination of stresses. In addi-tion, this approach makes it impossible to calculate equivalent stresses and obtain a complete picture of the stress-strain state of the joint. All this leads to the need to increase the factor of safety and, as a consequence, increase the number or diameter of rivets, which leads to an increase in the weight of the structure and its rise in price. The proposed method of calculating the connection by the finite element method allows to determine the stresses in all elements of the connection very accurately. This makes it possible to obtain a reliable picture of the stress-strain state of all elements of the compound. As a result, it is possible to reduce the complexity of the compound and its mass by reducing the number of rivets. The finite element method should be used to calculate critical compounds with complex operating conditions. The example of calculation of such connection is considered.
PDF

TRUSS DESIGN CALCULATION

https://doi.org/10.34031/2618-7183-2019-2-1-37-44
, ,
 37-44 p.
Abstract
The completeness of the truss design calculation is its configuration and dimensions when specifying the type of loading, material characteristics and directive dimensions. The problem of equilibrium stability with an unknown location of compressed rods hindered the optimization of the topology and geometry of the truss. The proposed variational method of truss synthesis is based on the principle of possible operation and generalization of the variational principles of Lagrange and Castigliano by expanding the functional space of geometric parameters. The solution of a physically linear isoperimetric problem for a given volume of the truss material allowed to establish its quasi-equal stress, which became the design criterion for the formulation of the geometry optimization problem. Its condition is the stationarity of the functional with respect to variable geometric parameters for a given flexibility of compressed rods. The iterative procedure, caused by a change in the initially accepted signs of longitudinal forces, is based both on their direct adjustment and on the change in the flexibility of individual rods. The global minimum of potential strain energy of the optimal truss is accompanied by a global minimum of material consumption. The proposed software allows to conduct automated design calculation of the truss. An example of designing a mechanical truss is considered.
PDF

VITREOUS PROTECTIVE AND DECORATIVE COVERINGS ON WOOD PARTICLE BOARD

https://doi.org/10.34031/2618-7183-2018-1-4-4-12
, , , ,
 4-12 p.
Abstract
Scientific and technological bases of receiving vitreous coverings on wood with use of a torch of low-temperature plasma are developed. Before plasma dusting of glass powders by grain structure 60-120mkm, the special protective coating protecting chipboard from destruction at high-temperature influence of a plasma stream on a front surface of the wood particle board (WPB) was applied. The structure of an intermediate protective coating including mix of a fine-grained glass powder and liquid glass is developed. Preliminary drawing an intermediate protective layer provides several consecutive technological operations.
For receiving vitreous coverings fight of colored and colourless glass are used which was previously ground in spherical porcelain mills. Optimum process parameters of plasma dusting of glass powder on the front surface of chipboard are developed. Optimum parameters of plasma melting is: current - 800A; operating voltage – 30B, a consumption of plasma-forming gas of argon 2m3/h.
Operational and aesthetic-consumer properties of vitreous protective and decorative coverings are investigated. It is established that vitreous protective and decorative coverings have the high durability of coupling with an intermediate protective layer. The received vitreous protective and decorative coverings on the basis of colored and colourless glass have the high water resistance, acid resistance, alkali resistance, as well as microhardness and high aesthetic performance.
The technology is recommended for widespread industrial introduction.
PDF