scholarly journals Investigation of the Influence of a Cavity Type Defect on the Frequencies of the Natural Rail Oscillations by the Radar Method

2019 ◽  
pp. 1006-1012
Author(s):  
Vadim S. Potylitsyn ◽  
Danil S. Kudinov ◽  
Ekaterina A. Kokhonkova
Keyword(s):  
Doppler Radar ◽  
Natural Oscillation ◽  
Rolling Stock ◽  
Destructive Testing ◽  
Natural Oscillations ◽  
Type Defect ◽  
Radar Method ◽  
Impulse Load ◽  
Oscillation Frequencies ◽  
Non Destructive

Currently, the problem of non-destructive testing of rail lashes or rolling stock is quite acute, as the demands of both speed characteristics and vehicle safety increase every year. Thus, the purpose of this study was to determine the possibility of recording frequencies of natural oscillations by the radar method for rail lashes and the influence of the dimensions of the cavity-type defect. For this purpose, a laboratory bench was created with a standard rail, the length of 1.19 m of the P-65 brand, in which free oscillations were excited using a shock impulse load. Measurements of natural oscillation frequencies of the rail were recorded on a 24-bit ADC and a specialized accelerometer ZETLAB BC110. To register the oscillations, a Doppler radar with a frequency of 10 GHz was used, which was installed at the focus of a parabolic mirror offset antenna with a 1.6-meter diameter. It was found that a “field” defect shifts the frequency mode of oscillation 750 Hz upwards. It is shown that the hole in the rail neck with a diameter of 10 mm makes a change in the frequency of about 14 Hz

RESULTS OF STUDIES OF OPERATION OF SPECIAL IMPEDANCE TRANSDUCERS ON THE RIGID METAL STRUCTURES OF REAL PRODUCED OBJECTS

2020 ◽  
pp. 44-49
Author(s):  
A. A. Arcentiev ◽  
A. M. Konovalov ◽  
V. I. Kugushev ◽  
S. S. Khudyakov
Keyword(s):  
Cooling System ◽  
Aggressive Medium ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Natural Oscillations ◽  
Energy Redistribution ◽  
Metal Structures ◽  
Mechanical Filter ◽  
Oscillation Frequencies ◽  
Non Destructive

The paper presents the studies of capabilities of special impedance transducers with mechanical filter of oscillation frequencies at the input (output) as a tool of non-destructive testing of real produced objects. Objects under test were elements of a power reactor, which are exposed to high temperature aggressive medium and which are inaccessible for direct contact because of the cooling system. The use of special transducers allowed the development of a new method, which used natural oscillations of the object under test and, thus, provided a mean for monitoring of inaccessible elements of the structure. The method is based on fixation of energy redistribution by the modes of natural oscillations of the object under test, when exposed to damping factors caused by cracks, erosion and other defects. It is shown, how this method operates, when using an artificial damper and in presence of real defects. The use of the artificial damper made it possible to determine that this method allowed the non-destructive testing over the entire surface of the monitored element of the structure.

scholarly journals AN ELECTROMAGNETIC METHOD FOR FREQUENCY ANALYSIS OF TRANSVERSE VIBRATIONS OF A BEAM

2020 ◽  
pp. 112-120
Author(s):  
F.Yu. Kuznetsov ◽  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Frequency Analysis ◽  
Natural Oscillation ◽  
Theoretical Description ◽  
Natural Oscillations ◽  
Technical Procedure ◽  
Transverse Vibrations ◽  
Sample Testing ◽  
Oscillation Frequencies

Vibration-based diagnostics of constructions is an obligatory technical procedure in mechanical engineering. In this regard, there is a problem of an adequate theoretical description of vibration processes in various structures with account for end fixity conditions, as well as the creation of experimental facilities for non-contact testing. The paper presents a theoretical basis and experimental verification results for a method of electromagnetic frequency analysis of rod systems. The essence of the method is the experimental determination of natural oscillation frequencies and their comparison with reference values. The main attention is paid to a theoretical description of transverse vibrations of a cantilever conductive rod in an external magnetic field in order to determine reference frequencies of a defect-free sample. The presence of the external magnetic field gives rise to the distributed electromagnetic force exerted on the rod. In the case of natural oscillations, the magnetic force is damping, which leads to a change in damping factors of partial oscillations. The electromagnetic effect is selective towards vibrational modes; hence, the damping factors of various partial oscillations of the rod vary to different degrees. This fact allows one to determine an optimal location of the area with acting magnetic field, as well as its width when measuring a given frequency of sample testing. The proposed method has several advantages: indestructibility of the sample, non-contact measurements, invariability of mechanical properties of the sample during the tests.

Evaluation of the Composite Barrier Natural Oscillations Influence on the Generated Shock Loading

2021 ◽  
pp. 103-113
Author(s):  
A.S. Borozenets ◽  
A.V. Proskurin ◽  
A.V. Shlishevskiy
Keyword(s):  
Test Object ◽  
Shock Loading ◽  
Natural Oscillation ◽  
Operating Conditions ◽  
Signal Spectrum ◽  
Natural Oscillations ◽  
Shock Loads ◽  
Frequency Determination ◽  
Prefabricated Structure ◽  
Oscillation Frequencies

The problem of studying behavior of various structures under the influence of intense impulsive (shock) loads arising during operation of many modern facilities, machines and devices remains relevant for many years. Shock loading in laboratory conditions is generated due to interaction between the test object and the braking device (barrier). In this case, braking device or barrier could be a one-piece or a prefabricated structure. If the braking device (barrier) dimensions commensurate with the test object, the braking device natural oscillation frequencies excited during interaction between the test object and the braking device (barrier) could be found in the range of the test object natural oscillation frequencies. Frequency determination within the signal spectrum registered on the test object and caused by oscillations of the braking device (barrier) or test equipment, would assist in better assessing the test object shock loading and its compliance with real operating conditions

scholarly journals Increase of informativity of two-frequency method of defectometry at ultrasonic control of details and units of railway rolling stock

2018 ◽  
Vol 77 (3) ◽  
pp. 182-187 ◽  
Author(s):  
A. N. Kireev
Keyword(s):  
Experimental Studies ◽  
Rolling Stock ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Frequency Method ◽  
Ultrasonic Control ◽  
Software Product ◽  
Non Destructive ◽  
Rolled Wheel ◽  
Railway Rolling Stock

When forecasting the technical state of the parts and units of railway rolling stock in operation, an important task is to determine the shape of the discontinuity in ultrasonic non-destructive testing in order to predict its behavior in further operation (this is especially important if the discontinuity in the results of such control is acceptable). Author proposed a solution for the improvement of the two-frequency defectometry method. A mathematical apparatus was developed and a method for determining the coefficient of the discontinuity shape was elaborate on its basis. The method makes it possible to determine the shape of both a point and an extended discontinuity. The software product NDTRT-07.03.01.18 was developed to automate calculations in determining the shape of discontinuity by a two-frequency method. The article gives a description of the experimental studies carried out to evaluate the reliability of the proposed method. This method can be used in determining the shape of the discontinuity in the details of the rolling stock, in which the defect can have a different shape, for example: cast wheel centers; various shaped castings used in the manufacture of rolling stock units (brackets for locomotive bogies, cast sidewalls for cars), as well as in parts manufactured by the method of plastic deformation, including wheel treads, axles, all-rolled wheels, rolled wheel centers, etc. In these details discontinuities are predominantly planar in nature, but voluminous discontinuities are also encountered - non-deformable nonmetallic inclusions, therefore the developed method can be applied to such objects of rolling stock railways.

Non destructive testing of works of art by terahertz analysis

2013 ◽  
Vol 64 (2) ◽  
pp. 21001 ◽  
Author(s):  
Jean-Luc Bodnar ◽  
Jean-Jacques Metayer ◽  
Kamel Mouhoubi ◽  
Vincent Detalle
Keyword(s):  
Non Destructive Testing ◽  
Destructive Testing ◽  
Works Of Art ◽  
Non Destructive
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