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  • Laboratory and industrial tests of the unit for methods of non-destructive testing of concrete elements

    Scientific-research Laboratory and industrial tests of equipment for NDT methods ZBK".The Department ELA RSSU conducted a series of laboratory and industrial tests of the device developed at the Department of ELAH for concrete structure NDT methods. A schematic and a description of the pathogen fluctuations and semiconductor receiver, as well as diagrams of dependence of the passage of the amplitude of oscillations of the pathogen in the concrete structure of the axial load.The most important results are obtained dependence of the amplitude of oscillations in ZBK from the amount of axial load from the composition of fillers experimental sample.

    Keywords: Nondestructive testing, reinforced concrete constructions, the causative agent of oscillations, the receiver oscillation, the amplitude of oscillations, axial load.

  • Calculation of strength of structures under breakaway

    Discusses the calculation of stress-strain State of glued structural sheathing to the test to determine the calibration of the test stand

    Keywords: Finite elements method, Stress concentration, Skin, Test, Prediction.

  • Optimization of the thick-walled spherical shell using strength theory of Mor

    The problem of optimization of thick-walled sphere loaded by internal and external pressures was solved. The essence of the method consists in the variation of the modulus of elasticity. The problem of finding the distribution of the characteristics of material in which the stress state is given, is called the inverse problem. The idea of the inverse method was proposed by academician of RAACS prof.  V.I. Andreev. The analytical dependence of modulus of elasticity from the radius at which the calculated stress on the strength theory of Mor is constant throughout the thickness of the shell was found. This shell will be equally stressed. If the strength characteristics of the material do not depend on the modulus of elasticity it will also be equiresistant. By creation of indirect heterogeneity we reduced the maximum tensions in 1.6 times. It was also shown that in the case of a centrally symmetric problem the second theory of strength is a particular case of the strength theory of Mor.

    Keywords: thick-walled spherical shell, optimization, strength theory of Mor, uniform strength, equal stress

  • Energy absorbing panel for seismic protection structures

    Currently actively developing direction of seismic protection, the identified using absorbing screens made in the form of sandwich structures. The present paper presents a design руктивная scheme of energy absorbing panel, which allows you to raise, if used, seismic stability of constructions.

    Keywords: Dynamic loading, uprugoplastichesky deformation, deformation chart, power absorption

  • Calculation of the strength of reinforced beams with an aggregate of bimodulus of elasticity material with the use of different theories of strength

    The paper considers arbitrarily supported arbitrarily loaded reinforced, beam with an aggregate of bimodulus of elasticity material. Formulas for determination of the tangential stresses arising in the aggregate, subject to the reinforced elements. Formulas are obtained for principal stresses occurring at an arbitrary point in the aggregate, as well as the equation for determining the point where major stresses reach extreme values. Are terms of strength as the classical theories of strength, and strength criteria applied for calculation of constructions made of bimodulus of elasticity material.

    Keywords: reinforced beam, bielastic modulus, stress, normal concrete, strength criteria.

  • Optimization of thick-walled concrete shell based on the solution of the inverse problem of mechanics of heterogeneous bodies

    We solved the problem of optimization of thick-walled prestressed concrete cylinder loaded by internal pressure. Preliminary stresses in such a cylinder are created by wounding with tension cables on the outer surface. The idea of the method is to find the law of variation of modulus of elasticity , in which the state of stress is given . The analytical dependence of modulus of elasticity of the radius at which the tensile stress in the entire thickness of the shell does not occure was found. By creation of indirect heterogeneity we reduced the consumption of rebar by 10%.  The direct problem - determining the stress- strain state of a cylinder with a constant modulus of elasticity was also resolved.

    Keywords: thick-walled prestressed concrete cylinder, optimization, inverse problem, theory of elasticity, heterogeneity

  • Method of calculation of power characteristics of belt elastic element

    Currently actively developing direction of seismic protection, the identified using absorbing screens made in the form of sandwich structures with упругопластическими energy-absorbing elements. In this article, on the basis of the conducted research and analysis, the formulas for the calculation of power characteristics of belt elastic element.

    Keywords: Dynamic loading, uprugoplastichesky deformation, deformation chart, power absorption

  • Construction of a model of equiresistant multispan beams

    Method of successive approximations was used to solve the problem of optimization of multispan continuous beam. Cross section of a beam was a welded I-beam.  By the variation of the width of the shelf we ensured that the maximum equivalent stress for energy theory of strength in each section is the same throughout. The solution is made numerically using complex MatLab. Bearing capacity of beams with variable stiffness along the length increased in 2 times in comparison with the beam with constant stiffness and the same mass. The proposed method can be applied to frames, taking into account the contribution of longitudinal forces in the equal stresses. Another effective way to change stiffness is to change the height of the wall of I-beam. In practice curvilinear shape of beams or shelves are not used because of complexity of manufacturing. They are replaced by the discrete form of cross section.

    Keywords: multispan beams, work method, optimization, uniform strength, welded I-beam, variable stiffness

  • Buckling of longitudinally compressed bars of variable stiffness creep

    The article is devoted to the stability of the polymer rods variable stiffness with the initial imperfec-tions and the development of creep deformation. The distinctive feature of the paper is a variable stiffness of the cross section and the use of fixing all, "seal-hinge" "seal, seal", "seal-free edge."

    Keywords: stability of rods, creep, highly elastic deformation, polymeric materials, coupling equation of Maxwell-Gurevich