The article proposes the derivation of resolving equations for the bending of triangular finite element of plate with regard to creep. In deriving of the equations we use Lagrange variational principle. The problem is reduced to a system of linear algebraic equations. Creep contributes only to the right side of the system of equations. These equations allow to calculate the plates of arbitrary shape, taking into account the viscoelastic properties of the material. An example of the calculation for a rectangular plate of a secondary polymeric PVC, hinged along the contour and loaded uniformly distributed over the area load is presented. As a law establishing a link between stress and creep deformation we used nonlinear equation of Maxwell-Gurevich. Calculations were performed in Matlab software package. The graphs of change in time of deflection and stresses are presented. Stress during creep vary slightly, a difference between the stresses at the beginning and end of creep process does not exceed 6%. The result of numerical calculation of the maximum deflection value at the end of creep is different from the theoretical on 0.26%.
Keywords: creep, finite element method, bending of plates, polymers, Maxwell-Gurevich equation, long cylindrical rigidity
The use of water resources to economic activity that is determined a necessity in human existence, all living beings and in almost all technological processes of industrial and agricultural production, fuel and energy complex and other industries, and other activities. At the modern stage of society development at the global level of the system ""Nature–Society–Man"" and the local level of basin geosystems, within which are formed the water resources, there is a strong tendency of the limited water resources within the bounding conditions for further development. Use of water within the local basin geosystems of the southern and Northern Caucasus the river Kuban, Terek and the Upper don, where more than 23 million people. (16.3 per cent of the total population of the Russian Federation)provided by the existing and newly built water system (WS) that in-basin and inter-basin regulation, redistribution of runoff (surface, underground), the selection of a water source and transportation of the estimated costs of water to a particular water user. The aim of the study is to develop a methodology basics of technical theory title of ""environment – Object of activity – Population"" existing in the composition of the WS, in which the main component is man-made hydraulic structures (HS), amending the natural processes of interaction between biotic and abiotic components, requiring a system of quantitative and qualitative assessment.
Keywords: water resources of the basin geosystems, water systems, natural and technological systems, monitoring, environmental safety, the object of activity, ecological conditions, the zone of influence
Are given the results of studies on the creation of samouplotnyayushchikhsya fine-grained fibrobetonov on the withdrawals of lithotrity with the application of a polyfunctional additive D -5. Are developed the compositions of samouplotnyayushchikhsya fine-grained fibrobetonov with the application of a basaltic fibre, which make it possible to considerably decrease the expenditure of cement and to improve the characteristics of fine-grained concrete mixture and concrete. The use of a polyfunctional additive D -5 in the mixtures makes it possible to increase the strength properties of fine-grained fibrobetonov with a simultaneous improvement in the rheological characteristics of concrete mixtures. The replacement of cement to 10 % from the mass by ashes of fraction d0,14 mm in the fine-grained concrete mixtures does not cause noticeable reduction in the strength properties of concrete. Developed samouplotnyayushchiesya fine-grained fibrobetony possess the increased strength properties and have low prime cost due to the use of local raw material and withdrawals of lithotrity
Keywords: cement, the withdrawals of lithotrity, ashes, polyfunctional additive D -5, basaltic fiber, samouplotnyayushchiysya fine-grained fibrobeton, strength for the bend and the compression, the mobility of mixture, the plan of the experiment
Modelling and experimental research of path filter of C range on opposing rods was made. In the paddband from 4 to 8 GHz losses were not more than 1.5 dB. Blocking at tuning downwards per 1 GHz was not less than 50 dB. Blocking at tuning upwards per 2 GHz was not less than 70 dB. There is a false passband 16.6 - 21.5 GHz.
Keywords: filter on opposing rods, modelling, experiment, wave centimetre range
The paper presents a technical-economic analysis of the perspective of development of domestic forestry machine-building in the conditions of import substitution. The authors substantiate and prove the prospects of using domestically produced harvesting machines in logging works, particularly the machines based on caterpillar tractors OTZ-300 and OTZ-400, fitted with modern foreign (in prospect - domestic) technological equipment. Using logging machines made by “Amkodor” company during cutting operations is also economically justifiable. In particular, in difficult natural-manufacturing conditions (the third category of soil) vehicle operating costs on a work cycle of machine complexes by the company “Ponsse” make 1081,7 rouble/m³, of machines by the company “Amkodor” – 848,4 rouble/m³, and of machines based on caterpillar tractors by LLC “OTZ” the costs make 407,7 rouble/m³ on the average. Specific capital costs are 2862, 1215,2 and 560,5 rouble/m³, respectively. Hence, we can draw a conclusion that machines and machine complexes based on caterpillar tractors of cross-country capacity provide stable productive work with high technical-and-economic indexes in difficult natural conditions.
Keywords: import substitution, logging machines, technical-economic analysis, perspectives
The article presents the quality assessment of repair work for electricity pilons of transmission line performed by the method of vibration diagnostics. The suggested criterion for assessing the quality of the repair is relative adhesion of repair layers to the base of the stand. Modeling of structural oscillations strut mount, transmission lines and calculations in the finite-element complex Ansys. The dependence of the parameters own frequency of fluctuations of the value of damage at different values of the space adhesion. The resulting equations based on changes in natural frequencies on the magnitude of adhesion. The calculation of the relative adhesion of the repair composition to the concrete model of the design. The material presented can be used for assessing the quality of repair work of different structures of the core type reinforced concrete structures.
Keywords: vibration diagnostics, quality, repair of structures, defect, adhesion, natural frequencies
Expediency of creating a method of complex estimation of investment projects in construction is substantiated in the article. The necessity of the accounting internal and external factors, their importance and trends, and also an inertance of manifestation factors are proved. The method is recommended to use for complex estimation of created and already realized investment projects in construction.
Keywords: investment project, complex estimation, efficiency, multicriteria optimization, fuzzy logic, construction
Thermoresistors nowadays are used not only as parts of temperature sensors and flowmeters but they are used as components of starting and control devices. Use of low-powered thermoresistors as starting and control devices parts needs a lot of devices that reduces equipment reliability. Current step-up running through motor-starting devices simplifies control circuit. For using thermoresistors in electric circuits with high-discharge rate it is necessary to use special constructions in order not to let termoresistor body be overheated. Thermoresistor expansion results in changing of thermal fields distribution pattern inside this semiconductor. The authors show calculated characteristics which let determine proportions and shapes of semiconductor subject to thermoresistor temperature.
Keywords: high power thermoresistors, thermoresistors of coaxial type, current density, temperature, analogy criterion, thermal conductance, temperature gradient, thermal field, stability criterion
One of the most important elements of the bridge, from which the service life of this structure directly depends, is the supporting part. It provides the movement and rotation of span structures, as well as the transfer of all loads from the forces acting on them to the supports. The task of the designer is to select such support parts, that could be allowed maximum reducing of the forces, acting at the ends of the beams and having a minimum resistance to their free movement. It is necessary in each case to select the support part, which will most closely meet the requirements. To solve this problem, the author structured and tabulated the kinds of support parts. And also an analysis of the main characteristics of some of them.
Keywords: bearing part, exothermia, bridge structure, durability, service life, transfer of loads and displacements, deforming systems, sliding systems, rolling systems
Created single-stage model of silicon solar cell using PC1D v.5.9 program, designed to simulate the photovoltaic devices. In the process of simulation change the level of doping and thickness of the n + type layer of the front, as well as applied texturing the front surface. The influence of the doping level and the thickness of the n + type layer in the photovoltaic solar cell characteristics. It was determined that with the increase of the doping level and the thickness of the front n + -layer a decrease in the efficiency of solar cells. It was found that the use of texturing the front surface leads to an increase in efficiency and is associated with reduced reflection losses and an increase in the photocurrent.
Keywords: Silicon solar cell thickness, doping levels, texturing, current-voltage characteristic
It describes the importance of urban development in national security, which is caused by the development of the defense infrastructure districts.
Keywords: city garrison, armed forces, defense, defense infrastructure
construction, road, system IndorCAD/Road, a digital model of geodetic engineering terms, design, transport system, transportation hub.
Keywords: construction, road, system IndorCAD/Road, a digital model of geodetic engineering terms, design, transport system, transportation hub
Currently, laser annealing are widely used to create a polycrystalline silicon film, which is promising for use in thin film solar cell, and transistors, liquid crystal displays and sensors due to recrystallization of amorphous and nanocrystalline silicon films. The study of morphology and surface conductivity of single-crystal silicon film on a glass substrate by laser annealing power. Laser annealing is carried Nd: YAG laser with a wavelength of 532 nm, speed of movement of the stage with a specimen of 5 mm/s and a laser power ranging from 34 to 86 watts. The laser beam was focused on the sample in the form of a narrow line width of 10 microns and 60 mm in length. The dependence of the size of the nanocrystals and the conductivity of silicon films on the power of the laser annealing radiation. It is shown that the power of the laser radiation in the range of 60 to 70 W is optimal for the best electrical parameters silicon film for the purpose of its use in high-performance thin-film solar cells.
Keywords: silicon film, laser annealing, surface morphology, electrical conductivity, thin film solar cell
The calculation of multi-storey reinforced concrete frame building, consisting of apartments, offices and underground parking, against progressive collapse is presented in the paper. Two different ways of simulation of reinforced concrete building against progressive collapse are suggested, needed for estimation of survivability of building structures. The technique, which allows to carry out the stability of reinforced concrete structure to resist progressive collapse, is presented. This method is based on a nonlinear analysis of framed structures under the special load combination and includes dead and live loads, implying that the loading process modeling is fulfilled on the basis of the adjusted step method. The last one is of great importance for simulation of the processes in the whole life cycle of structures. The obtained results show that the offered strength calculation method of the framed structure against progressive collapse considers both geometric and material nonlinearity and also allows to assess survivability of the construction under conditions of emergency events and its stability to resist against progressive collapse. The step method of solving nonlinear problems, applied for modeling of collapse process, is shown to be more appropriate for these cases. We conclude that applying the proposed method of calculation results in more economic use of materials, giving evidence of its effectiveness.
Keywords: progressive collapse, survivability of building structures, computer simulation, structural elements, nonlinear analysis, stability, geometric and material nonlinearity, the step method
A numerical model of the laser annealing TiO2 film on the TCO / glass substrate with radiation of a wavelength of 1064nm (Nd: YAG laser) to the crystallization and its use in solar cells perovskite. The modeling used a numerical finite difference method for solving a system of one-dimensional unsteady heat conduction differential equations. As a result, laser annealing temperature distribution obtained in the process of modeling the structure of TiO2 / TCO / glass substrate by varying the laser power. It is shown that a high laser power (30-100 watts) is enough for an effective transition organometallic precursor of TiO2 in the crystalline phase of anatase TiO2 (transition temperature of 400-600 °C) for a short period of time (60 sec.) due to the direct absorption of photons laser radiation. It is found that for experimental studies should be used laser power of 30-70 watts, since a higher power (e.g., 100 W) raises the temperature of the substrate above its melting point (for example, for glass 650 ° C).
Keywords: Numerical modeling, laser annealing, TiO2 film, heat equation, solar cell