NONLINEAR TRANSVERSE VIBRATIONS OF COMPOSITE RODS UNDER THE ACTION OF A STATICALLY APPLIED TRANSVERSE LOAD

Nonlinear transverse vibrations of composite rods pre-loaded with lagging arranged symmetrically on both sides of the axis of the composite rod under the action of a statically applied transverse load are investigat-ed. The cases of attaching the lagging only to the ends of the composite rod, as well as when the laggings are continuously attached to the composite rod along its entire length, are considered. The results of the study of nonlinear transverse vibrations of composite rods under the action of a statically applied transverse load are presented. When conducting studies of transverse vibrations of composite rods, solutions of differential equations of vibration of prestressed through beams and stiffening cores of high-rise buildings are obtained. The obtained differential equations of vibration of composite rods allow us to determine the dynamic char-acteristics of prestressed through beams under various linear and boundary conditions. A method for com-posing differential equations of free and forced oscillations of prestressed through beams and stiffening cores of high-rise buildings and solving differential equations under various linear and nonlinear boundary conditions is developed. Expressions are given for determining the longitudinal forces and torques at the ends of the rod at any lo-cation of the lagging from the axis and at any different stiffness of the lagging

Polarization-Independent Circulator Based on Composite Rod of Ferrite and Plasma in Photonic Crystal Structure

We propose a type of polarization-independent circulator based on a composite rod of ferrite and plasma materials in a two-dimensional photonic crystal (PhC) slab. Only one composite rod was set at the center of the structure to provide circulation for both TE- and TM-polarized waves. Additionally, to improve the performance of the circulator, three additional rods were inserted to improve the coupling condition between the center magneto-optical microcavity and the corresponding waveguides. Finite element method was used to calculate the characteristics of the structure and the Nelder–Mead optimization method was employed to obtain the optimum parameters. The results show that a low insertion loss (~0.22 dB) and high isolation (~14 dB) can be achieved in our structure for waves of both TE and TM polarizations. The idea presented here may be useful for designing compact polarization devices in large-scale integrated photonic circuits.

EXPERIMENTAL RESEARCH METHODOLOGY OF ELEMENTS WITH COMPOSITE FITTINGS WITH BENDING AT PRIORITY SECTIONS

The inability of using this type of reinforcement as a cross on the support sections of the bent elements is one of the reasons limiting the wide use of composite rod reinforcement. To ensure the strength of bent elements along inclined sections, it is proposed to bend the rods of the working longitudinal working reinforcement, and geometric parameters of bends for some types of composite reinforcement are proposed, depending on the diameter of the rod. To develop a method for calculating the strength of inclined sections, it is necessary to develop experimentally justified prerequisites that take into account the features of joint operation of composite rod reinforcement in inclined sections. The article offers a method for experimental study of the strength and crack resistance of reinforced concrete bending elements with non-metallic composite rod reinforcement, including the design of prototypes, the installation scheme of devices during testing. The developed method allows to determine the parameters of strength and crack resistance of inclined sections of bent elements. The tasks of experimental studies of concrete elements reinforced with composite rod reinforcement are to determine the regularity of changes in the stress-strain condition of concrete and composite reinforcement during loading, to determine the nature of the destruction of elements along the inclined section, to obtain data on the strength and crack resistance of elements.