scholarly journals On the assessment of the potential for extracting information on defects in the main pipeline by the method of radar analysis of natural oscillation frequency

2021 ◽  
Vol 2094 (4) ◽  
pp. 042030
Author(s):  
O A Maykov ◽  
E A Kokhonkova ◽  
T N Baturin
Keyword(s):  
Oscillation Frequency ◽  
Natural Oscillation ◽  
Frequency Characteristics ◽  
Main Pipeline ◽  
Natural Oscillations ◽  
Vibration Method ◽  
Main Pipelines ◽  
Formation Of Cracks ◽  
The Difference ◽  
Natural Oscillation Frequency

Abstract The paper deals with the issue of diagnostics of main pipelines by the vibration method, exploring the influence of the formation of cracks in the walls of the pipeline on the change in the frequency characteristics of the pipeline. By analyzing the difference in the natural oscillation frequency of a pipe with a crack and without it, it is possible to assess the location of the defect with a certain accuracy. The issue of the possibility of reading the natural oscillations of the main pipeline from the surface of the soil located above the pipeline is also being studied.

scholarly journals Experimental study of a lock-in phenomenon in the case of a mechanical oscillator flowmeter

Mechanik ◽  
2020 ◽  
Vol 93 (7) ◽  
pp. 13-15
Author(s):  
Maciej Szudarek ◽  
Mateusz Turkowski
Keyword(s):  
Experimental Study ◽  
Pulsatile Flow ◽  
Oscillation Frequency ◽  
Measurement Errors ◽  
Natural Oscillation ◽  
Mechanical Oscillator ◽  
Pulsation Amplitude ◽  
Lock In ◽  
Natural Oscillation Frequency

Oscillatory flowmeters are susceptible to pulsatile flow and mechanical oscillator flowmeters are no exception. The experimental study was conducted to determine possible measurement errors for specific pulsation amplitude thresholds. The study verified that no frequency lock-in takes place for pulsation frequencies which are subharmonics of the natural oscillation frequency, nor for harmonics higher than the 2nd.

Vibration Control of Oscillating System Based on Governing Visco-Elastic Characteristics of Absorber by Means of External Electric Signal

2008 ◽  
Vol 144 ◽  
pp. 220-225 ◽  
Author(s):  
V.A. Bilyk ◽  
E.V. Korobko ◽  
G.N. Reizina ◽  
E.A. Bashtovaya ◽  
E.B. Kaberdina ◽  
...  
Keyword(s):  
Shear Stress ◽  
Oscillation Frequency ◽  
Electric Field Intensity ◽  
Natural Oscillation ◽  
Smart Devices ◽  
Electric Signal ◽  
Oscillating Systems ◽  
Damping Decrement ◽  
Natural Oscillation Frequency ◽  
Elastic Characteristics

Electro-rheological fluids (ERF) allow us to create «smart» devices. One of the basic directions of application of such materials is damping in oscillating systems. This work describes simulation model and offers the results of experimental research by rheological properties and damping characteristic of ERF. Control signal is defined by electric field intensity, which is changed within the bounds of 0…0.5 kV/mm. Amplitude of oscillation – up to 5 mm, oscillation frequency is modified within the bounds of 0.5…5 Hz. The logarithmic damping decrement and natural oscillation frequency of oscillating system, shear stress and viscosity of ERF are determined.

scholarly journals INFLUENCING OF THIN PROTECTIVE COATINGS ON NATURAL FREQUENCIES OF RADIAL OSCILLATIONS OF CLADDINGS OF FUEL RODS OF NUCLEAR REACTORS

2020 ◽  
pp. 147-153
Author(s):  
Yu.E. Mazurenko ◽  
Yu.V. Romashov ◽  
A.G. Mamalis
Keyword(s):  
Oscillation Frequency ◽  
Natural Frequencies ◽  
Nuclear Reactors ◽  
Protective Coatings ◽  
Natural Oscillation ◽  
Fuel Rods ◽  
Natural Oscillation Frequency

The natural frequencies and the modes of the radial oscillations are computed by using the method of grids for the cylindrical claddings made with the thin protective coatings for the fuel rods of the nuclear reactors. It is received the values more than 150 kHz for first natural frequencies of the radial oscillations of the claddings of fuel rods of the WWER-1000 nuclear reactors. It is shown that the thin protective coatings lead to noticeable increasing of first natural oscillation frequency, but have negligible influencing on the second and higher natural frequencies as well as on the modes of the radial oscillations of the claddings of fuel rods.

scholarly journals A Two-Mass Gyro-Particle as a Tool for Supersonic Aeroelasticity Analysis

2020 ◽  
pp. 62-73
Author(s):  
S.V. Arinchev
Keyword(s):  
Oscillation Frequency ◽  
Aerodynamic Drag ◽  
Natural Oscillation ◽  
Rotational Frequency ◽  
Pulsation Frequency ◽  
Supersonic Speed ◽  
Flow Modelling ◽  
Multiple Frequencies ◽  
Natural Oscillation Frequency ◽  
2D Model

When a flying vehicle reaches a high supersonic speed, plasma occurs in the flow, hampering the application of the traditional piston theory and its modifications to solve the aeroelasticity problem. This work considers flow modelling using a system of two-mass gas gyro-particles capable of dividing into two charges and ionizing the flow. The two-mass gas gyro-particle has two elements and two pairs of multiple frequencies. As the gyro-particle interacts with the surface of an elastic body, it starts to rotate and pulsate, and the multiple frequencies split. As the pulsation frequency of the gas gyro-particle reaches the natural oscillation frequency of the elastic structure, resonance occurs and the structure flutters. It is assumed that the supersonic character of the flow is determined not by the velocity of the flying vehicle, but by the rotational frequency of the gas gyro-particle. The higher the particle’s rotational frequency, the higher the aerodynamic drag. If the rotational frequency is high enough, then the screening effect takes place: the vehicle decelerates and turns upside down. This is called divergence, and the plasma is not taken into account. In this work, a 2D model is used to interpret the flutter and the divergence effects.

scholarly journals Approximate Calculation of the Natural Oscillation Frequency of the Vibrating Table in Inter-Resonance Operation Mode

2021 ◽  
Vol 71 (2) ◽  
pp. 151-166
Author(s):  
Maistruk Pavlo ◽  
Lanets Oleksii ◽  
Stupnytskyy Vadym
Keyword(s):  
Natural Frequency ◽  
Oscillation Frequency ◽  
Approximate Calculation ◽  
Ritz Method ◽  
Operation Mode ◽  
Natural Oscillation ◽  
Ansys Software ◽  
Distributed Parameters ◽  
Vibrating Table ◽  
Natural Oscillation Frequency

Abstract The first natural frequency of oscillations of the vibrations of a discrete-continuous interresonant vibrating table plate was found using the functions of the Krylov-Duncan. The continuous member, presented in a plate hinged at four points, is used as a reactive mass with distributed parameters to create an inter-resonance vibrating table with an electromagnetic drive. For this purpose, the plate was considered as a rod on hinged supports. The justification of this approach is confirmed by simulation in the Ansys software. The results were confirmed using the approximate Rayleigh-Ritz method. The geometric shape of the plate is reduced to a section of a hyperboloidal surface. The results of simulation of the first natural frequency were verified experimentally.

scholarly journals EXPERIMENTAL INVESTIGATION OF TRANSITIONAL PROCESSES OF THE INERTIVE DRIVE VIBRATION MACHINE

2021 ◽  
pp. 153-156
Author(s):  
Dmytro Kononov ◽  
Yevhen Miroshnyk
Keyword(s):  
Experimental Investigation ◽  
Resonant Frequency ◽  
Oscillation Frequency ◽  
Variable Mass ◽  
Linear Acceleration ◽  
Natural Oscillation ◽  
Vibration Machine ◽  
Vibrating Screen ◽  
Transitional Processes ◽  
Natural Oscillation Frequency

Purpose: to study the transients in the vibrating machine that accompany the start from rest and run out.The studies were performed on a laboratory vibrating screen. The screen is driven by an adjustable drive - a single-shaft inertial vibrator, which has imbalances with variable mass. The screen has a resonant setting, ie h natural oscillation frequency is less than the frequency of the forcing force of the drive.The GY-521 module with the MPU6050 chip is used to measure the kinematic characteristics. This module allows you to measure linear acceleration and angular velocity.The graphs show typical graphs of changes in the acceleration points of the vibrating screen box at full cycle: from start to complete stop.The graphs show the run-out (stop) areas of the screen. There is an increase in the amplitude of the oscillation of the acceleration of the screen box during the passage of the resonant frequency. This phenomenon is characteristic of the vibrating machine with a resonant setting.

scholarly journals Analysis of the natural oscillation frequency of the long-span trusses with flanged connections

2021 ◽  
pp. 76-85
Author(s):  
Татьяна Георгиевна Рытова ◽  
Людмила Анатольевна Максимова ◽  
Анастасия Георгиевна Николаева ◽  
Татьяна Михайловна Макарова ◽  
Надежда Георгиевна Пфаненштиль
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Frequency ◽  
Natural Vibration ◽  
Natural Oscillation ◽  
Natural Vibration Frequency ◽  
Building Structures ◽  
Long Span ◽  
Local Areas ◽  
Calculation Results ◽  
Natural Oscillation Frequency

Приводится анализ частоты собственных колебаний большепролетной фермы с фланцевыми соединениями. Выполнен расчет фланцевого соединения с различными случаями исключения болтов из работы соединения. Анализ результата расчета показал, что возникновение повреждений и дефектов конструкций здания в локальных зонах, величина которых несущественно снижает общую жесткость каркаса, практически не влияет на динамические характеристики каркаса. The analysis of the natural vibration frequency of a large-span truss with flanged connections is given. The calculation of the flange connection with various cases of exclusion of bolts from the connection operation is performed. Analysis of the calculation results showed that the occurrence of damage and defects in the building structures in local areas, the value of which significantly reduces the overall rigidity of the frame, practically does not affect the dynamic characteristics of the frame.

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