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  • Analysis of methods for determination of parameters of beam amplitude-frequency characteristic

    Mechanical systems oscillate relative to the equilibrium position, and their amplitude depends on both frequency and mass, shape, design and mechanical properties of the system. There are two parameters of the grequency response of mechanical systems: the frequency of their natural vibrations and dynamicity on the effect of forced vibrations (dynamic coefficient). The purpose of the article is to investigate methods for calculating the parameters of the frequency response such a frequency of natural vibrations and the dynamic coefficient of a cantilevered steel beam. The methods which were used are analytical, finite element method with the ANSYS software environment and experimental method on the vibration stand with two loading methods: sinusoidal vibration using the swinging frequency method and broadband random vibration. The obtained natural oscillation frequency values are consistent within the relative error of 15%, dynamic coefficient values are consistent within the relative error of 5%. The finite element method is well consistent with the analytical method, while it requires fewer operations for more complex designs. Differences in the results of experiments arise from differences in the methods of loading the object of research.

    Keywords: frequency response, finite element mathod, ANSYS, natural vibrarion frequency, sweep check, broadband random vibration

  • Liquid glass and aqueous solutions of silicates, as a promising basis for technological processes of new nanocomposite materials

    The properties of the water-soluble high-modulus silicate systems: based on alkali metal polysilicates called liquid glass and chain their transformation from lower to higher oligomers, with the subsequent formation of colloidal solutions - silica sol. The methods of preparation, properties and applications of water-soluble high-modulus silicate systems. The possibilities of their use as a binder and modifying agents for various nanostructured composite materials. The examples of promising areas of application of liquid glass and high modulus of aqueous solutions of silicates in construction and industry. In particular show the possibility of using liquid glass and aqueous solutions of silicates in the production of nanostructured silicate polymer. In space engineering for manufacturing water-destructed mandrels used in the manufacture of solid rocket motor casings and pressure vessels 'cocoon' of composite materials by winding. The application of the inorganic sol to obtain a nanocomposite ceramics and monolithic blocks of silicon oxide, which can be used in various fields of modern technology. The possibility of using silica sol as a binder for refractory ultra-lightweight shielding materials used to protect equipment from high impacts. The directions of development of the production of new acid-resistant materials and linings for protection of chemical equipment, parts and components operating in corrosive environments.

    Keywords: Keywords: water glass, silicate polymer concrete, additives, silicates organic bases tetrafurfuriloksisilan, furfural alcohol, nanostructure composite materials, water-soluble silicates, silica sol, sol-gel transition, cured xerogel water-destructed mandr