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  • Документ
    Modeling of crack growth process in spatial bodies under cyclic loading condition
    (KNUCA, 2014) Bazhenov, V.; Pyskunov, S.; Shkryl, O.
    The algorithm for finite element modeling of fatigue cracks growth in the spatial bodies under cyclic loading using semianalytic finite element method (SFEM) is presented. The crack growth process is described by Paris' equation, stress intensity factor (SIF) is determined by the direct method. Testing of the algorithm is executed on the problem of the development of an elliptical crack in a prismatic body under the action of cyclic loading.
  • Документ
    A finite element technique and results of continual fracture process modeling
    (KNUCA, 2014) Bazhenov, V.; Pyskunov, S.
    The techniques of modeling of continual fracture process for space circular and prismatic bodies under long-term static or cyclic force loading condition and some results of determination of responsible parts lifetime is presented in this paper. The scalar damage parameter is used to describe the material continual fracture process. A stress-strain problem solution made with semianalytic finite element method (SFEM). It‘s shown , that the value of residual lifetime could be differ significantly for different loading condition and object configuration.
  • Документ
    Analysis of space planning and design decisions modern cottage
    (KNUCA, 2014) Klys, M.
    This article report analysis of the major space planning and design solutions to contemporary cottages. Also considered the land on which built or being built these cottages. Realized statistical processing of the results. Definitely, a line of research of technical parameters of the device bearing structures cottages. Inspected the 68 modern houses and land plots for them in Kiev and Kiev region. Based on these data the histogram parameters most significantly influence the choice of process parameters erection. The results of analysis are a set of body-planning and design parameters that significantly affect the technological solutions.
  • Документ
    Analysis of modified bitumen difference polymers
    (KNUCA, 2014) Onischenko, A.; Kuzmіnets, M.; Aksenov, S.
    An important step in the preparation of modified bitumen is selection of the composition and verification of various polymers’ effectiveness. Therefore, paddle mixers are widespread in both industrial and laboratory conditions for efficient mixing of bitumen with polymers. The developed method allows to determine the completion time of modification process at various process parameters (temperature, mixing speed and content of the modifier) to complete stabilization of the properties and the homogenization of bitumen. The results of studies showed that optimal time for bitumen modification at wich take place both stabilization of the properties and homogenization, ie astringent take the necessary level of uniformity with latex Butonal NS198, is about 3 hours.
  • Документ
    Application of generalized "method of lines", for solving problems of thermoelasticity of thick plates
    (KNUCA, 2014) Chybiryakov, V.; Stankevich, A.; Levkivskiy, D.; Melnychuk, V.
    In this paper, a new combined method of reducing dimensions of spatial thermoelasticity problems was proposed; based on the “method of lines”, combined with Bubnov-Galerkin-Petrov`s projection method which significantly expands its capabilities. The generalized “method of lines” can be used for plates of variable thickness, in problems of dynamics and thermoelasticity. The basic idea is to reduce the dimension of the spatial coordinates using the projection method, with a system of basis functions. This article is the first part of the work. It shows the reduced differential equations and proposes a new way of modeling boundary conditions.
  • Документ
    Calculation of deflection of one- and two-layer slabs supported on four sides
    (KNUCA, 2014) Smorkalov, D.
    Presented method and results of experimental research of deflection of one-layer and two-layer slabs influenced by short-term lateral load. Proposed method of calculation based on the limit equilibrium method, calculation of slab deflections values by LIRA-CAD bundled software. The comparison of experimental and theoretical results of the calculation of deflections slabs.
  • Документ
    Development of Ukraine territory flooding processes; Its parameters and the influence on the environmental safety level
    (KNUCA, 2014) Voloshkina, O.; Bereznitska, J.
    Shows the present state of development of flooding processes of Ukraine territory. Given filtration stages in the flooding the process of and methods of their calculation. The method of filtration resistance for calculating of the filtering in flooding process is analyzed. Shows the dependence between the development of flooding process and intensifying processes of landslides on Ukraine territory.
  • Документ
    Optimization of motion regimes for machines and mechanisms with a mehatronics control
    (KNUCA, 2014) Lovejkin, V.; Chovnyuk, Y.; Romasevich, Y
    Motion control of machines and mechanisms with a mechatronics control is now recognized as a key technology in mechatronics. The robustness of such motion control will be represented as a function of stiffness and a basic for practical realization, for example, in the precise agriculture. Target of such motion is parameterized by control stiffness which could be variable according to the task reference. However the system robustness of motion always requires very high stiffness in the controller. The paper shows that control of acceleration realizes specified motion simultaneously with keeping the robustness very high. The acceleration is a bridge to connect such robustness and variable stiffness. For practical applications, a technique to estimate disturbance is introduced to make motion controller to be an acceleration controller of machine/mechanism. Optimization of motion control of flexible structure and identification of mechanical parameters are also described.
  • Документ
    Progress in cement science - why alkaline activation?
    (KNUCA, 2014) Krivenko, P.
    Fifty years ago just an idea of the presence of free alkalis in a cement matrix was considered by the ordinary portland cement (OPC) people as an absurd one and this was a basic postulate accepted in the chemistry of cements. In 1957 a scientist from Ukraine (USSR) Victor Glukhovsky put forward an assumption which was taken as a base for development and bringing into practice of construction a principally new class of cementitious materials which first appeared in the art under a name of “alkaline cements” (now also known under a general name of “alkali-activated cements (AAC)”. A validity of these ideas is confirmed by more than 50 years of evolutional development and vast experience collected from practical use of new materials in a variety of large-scale applications. A present review covers theoretical views on role played by alkali in cement stone structure formation. Examples of compositional build-up of the alkali- activated cementitious materials as a function of quantity of alkali and type of aluminosilicate component are reported as well as the results of inspection taken over the AAC concrete structures made with these cements.
  • Документ
    The principles of discrete modeling of rod constructions of architectural objects
    (KNUCA, 2014) Kulikov, P.; Ploskiy, V.; Skochko, V.
    This article describes the basic principles of rod spatial building constructions modeling by means of discrete geometry. The mathematical dependence that form the basis of this approach are the differential regularities between the geometric and physical parameters of the modeled constructions, as well as the parameters of the external loads which determine the final shape of the model.