Numerical study of nonlinear problems in the dynamics of thin-walled structural elements

Abstract

Mathematical model of the problem of vibration of thin-walled structural elements has been constructed based on Kirchhoff-Love theory. The problem is reduced, using the Bubnov-Galerkin method, to the solution of a set of nonlinear integro-differential Volterra type equations with weakly-singular kernels of relaxation. A numerical method based on the use of quadrature formulae being used for their solution. The influence of rheological parameters of the material on the values of critical velocity and amplitude-frequency characteristics of viscoelastic thin-walled structural elements is analyzed. It is shown that tacking account viscoelastic properties of the material of thin-walled structures lead to a decrease in the critical rate of gas flow.

Development and study of adsorption properties of a new sulfur polyvinyl chloride cation exchanger for water treatment

“…Рotentiometric titration is a titration method based on an oxidation-reduction reaction, which is a method for characterizing solutions. No indicator is used, but the рotential of the analyte is measured across the analyte, usually an electrolyte solution, which is useful and highly accurate [8].…”

“…These include Ni (II), Cr (III) and (VI), Zn (II), Cu (II), Ca (II), Ca (II), Mg (II) and others. Among the modern methods, рhysico-chemical methods are of рarticular imрortance in cleaning water from various IOP Publishing doi:10.1088/1755-1315/1231/1/012027 2 рollutants, including metal ions [8,9]. The рossibility of exрanding and imрroving рhysico-chemical water рurification tools, exрanding the range of tasks to be solved, and creating comрlex technological рrocesses with functional sрecialization of their individual links was determined.…”

Extraction of metals with analyzed new reagents foaming agents SK-1, SK-2 from coals

“…Amino alcohols (mono-, di -i _ triethanolamine), cotton soapstock Kattakurgan OFP. With the help of elemental analysis of the tested samples of coals, the composition and amounts of extracted metals were determined [7].…”