Исследование случаев «аномального» затухания ультразвуковых колебаний в заготовках из никелевых жаропрочных сплавов

2020 ◽  
pp. 37-47
Author(s):  
М.А. Далин ◽  
В.Ю. Чертищев ◽  
И.С. Краснов ◽  
А.Н. Раевских
Keyword(s):  
Ultrasonic Attenuation ◽  
Signal Amplitude ◽  
Coarse Grained ◽  
Non Destructive Testing ◽  
Echo Signal ◽  
Destructive Testing ◽  
Workpiece Surface ◽  
Amplitude Attenuation ◽  
Non Destructive ◽  
Longitudinal Ultrasonic Wave

An ultrasonic non-destructive testing has found out a new phenomenon in several stamped forgings made from heat-resistant nickel alloys (Ni-superalloys) of two grades: local attenuation of the bottom echo signal amplitude, when the workpiece surface had large (over 20 mm) randomly located zones with significant (up to 1.5%) fluctuations of the longitudinal ultrasonic wave propagation velocity. On top of that, there were no various grain sizes or coarse-grained structures that usually lead to a an increase of a rate of ultrasonic attenuation in such alloys, and which triggers off a bottom echo signal amplitude attenuation. The Article states the studies carried out to explain the tangible reasons of the detected macroinhomogeneity of the velocity, and how it associated with a bottom signal amplitude attenuation.

scholarly journals Comparison of Sandstone Damage Measurements Based on Non-Destructive Testing

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5154
Author(s):  
Duohao Yin ◽  
Qianjun Xu
Keyword(s):  
Elastic Modulus ◽  
Wave Velocity ◽  
Damage Variable ◽  
The Other ◽  
P Wave ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
P Wave Velocity ◽  
Amplitude Attenuation ◽  
Non Destructive

Non-destructive testing (NDT) methods are an important means to detect and assess rock damage. To better understand the accuracy of NDT methods for measuring damage in sandstone, this study compared three NDT methods, including ultrasonic testing, electrical impedance spectroscopy (EIS) testing, computed tomography (CT) scan testing, and a destructive test method, elastic modulus testing. Sandstone specimens were subjected to different levels of damage through cyclic loading and different damage variables derived from five different measured parameters—longitudinal wave (P-wave) velocity, first wave amplitude attenuation, resistivity, effective bearing area and the elastic modulus—were compared. The results show that the NDT methods all reflect the damage levels for sandstone accurately. The damage variable derived from the P-wave velocity is more consistent with the other damage variables, and the amplitude attenuation is more sensitive to damage. The damage variable derived from the effective bearing area is smaller than that derived from the other NDT measurement parameters. Resistivity provides a more stable measure of damage, and damage derived from the acoustic parameters is less stable. By developing P-wave velocity-to-resistivity models based on theoretical and empirical relationships, it was found that differences between these two damage parameters can be explained by differences between the mechanisms through which they respond to porosity, since the resistivity reflect pore structure, while the P-wave velocity reflects the extent of the continuous medium within the sandstone.

Исследование выявляемости поверхностных плоскостных дефектов ультразвуковым методом с применением волн Рэлея

2021 ◽  
Vol 6 ◽  
pp. 26-34
Author(s):  
Н.П. Алешин ◽  
Н.В. Крысько ◽  
С.В. Скрынников ◽  
А.Г. Кусый
Keyword(s):  
Experimental Studies ◽  
Signal Amplitude ◽  
Probability Of Detection ◽  
Non Destructive Testing ◽  
Electromagnetic Acoustic Transducer ◽  
Destructive Testing ◽  
Testing Method ◽  
Acoustic Transducer ◽  
Non Destructive ◽  
Planar Flaw

The issues of detecting operational surface planar flaws by the ultrasonic non-destructive testing method with the use of Rayleigh surface waves generated by an electromagnetic-acoustic transducer are considered. The paper presents experimental studies of planar defects detection, simulated by an artificial reflector of the "notch" type with different width, depth and angle of inclination. The dependences of the signal amplitude on the listed parameters are constructed and their character was estimated. The optimal amplitude models for constructing the probability of detection curves (PoD) have been determined. A conclusion is made about the minimum dimensions of an operational planar flaw detected by the considering method with a probability of 90%, taking into account the confidence interval of 95%.

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

Modeling of a sensitive element on a planar mushroom-shaped metamaterial for non-destructive testing and searching for inhomogeneities in technological media

2020 ◽  
pp. 54-59
Author(s):  
A. A. Yelizarov ◽  
A. A. Skuridin ◽  
E. A. Zakirova
Keyword(s):  
Sensitive Element ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Resonant Frequency Shift ◽  
Maltese Cross ◽  
Informative Parameters ◽  
Non Destructive ◽  
Cross Type ◽  
Electrodynamic Structure ◽  
Electrophysical Parameters

A computer model and the results of a numerical experiment for a sensitive element on a planar mushroom-shaped metamaterial with cells of the “Maltese cross” type are presented. The proposed electrodynamic structure is shown to be applicable for nondestructive testing of geometric and electrophysical parameters of technological media, as well as searching for inhomogeneities in them. Resonant frequency shift and change of the attenuation coefficient value of the structure serve as informative parameters.

STUDY OF HOMOGENEITY, POROSITY AND INTERNAL DEFECTS IN AERATED AND EPS AGGREGATE POLY BRICKS USING NEUTRON RADIOGRAPHY TECHNIQUE

2015 ◽  
Vol 7 (2) ◽  
pp. 1428-1439
Author(s):  
Khurshed Alam ◽  
Md. Sayeedur Rahman ◽  
Md. Mostafizur Rahman ◽  
S. M. Azaharul Islam
Keyword(s):  
Optical Density ◽  
Neutron Radiography ◽  
Density Variation ◽  
Expanded Polystyrene ◽  
Elemental Distribution ◽  
Non Destructive Testing ◽  
Internal Defects ◽  
Destructive Testing ◽  
Radiographic Images ◽  
Non Destructive

A powerful non-destructive testing (NDT) technique is adopted to study the internal defects and elemental distribution/homogeneity and porosity of aerated brick and EPS aggregate poly brick samples. In the present study the internal defects like homogeneity, porosity, elemental distribution, EPS aggregate and aerator distributor in the test samples have been observed by the measurement of gray value/optical density of the neutron radiographic images of these samples. From this measurement it is found that the neutron intensity/optical density variation with the pixel distance of the AOI of the NR images in both expanded polystyrene (EPS) aggregate poly brick and aerated brick samples comply almost same in nature with respect to the whole AOI but individually each AOI shows different nature from one AOI to another and it confirms that the elemental distribution within a AOI is almost homogeneous. Finally it was concluded that homogeneity, elemental distribution in the EPS aggregate poly brick sample is better than that of the aerated brick sample. 

Non-Destructive Testing of Thermoplastic Carbon Composite Structures

2020 ◽  
Vol 2020 (1) ◽  
pp. 34-52
Author(s):  
Rafał Szymański
Keyword(s):  
Composite Structures ◽  
Ultrasonic Method ◽  
Composite Panel ◽  
Aviation Industry ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Pulse Technique ◽  
Thermoplastic Matrix ◽  
The Subject ◽  
Non Destructive

AbstractThe article is in line with the contemporary interests of companies from the aviation industry. It describes thermoplastic material and inspection techniques used in leading aviation companies. The subject matter of non-destructive testing currently used in aircraft inspections of composite structures is approximated and each of the methods used is briefly described. The characteristics of carbon preimpregnates in thermoplastic matrix are also presented, as well as types of thermoplastic materials and examples of their application in surface ship construction. The advantages, disadvantages and limitations for these materials are listed. The focus was put on the explanation of the ultrasonic method, which is the most commonly used method during the inspection of composite structures at the production and exploitation stage. Describing the ultrasonic method, the focus was put on echo pulse technique and the use of modern Phased Array heads. Incompatibilities most frequently occurring and detected in composite materials with thermosetting and thermoplastic matrix were listed and described. A thermoplastic flat composite panel made of carbon pre-impregnate in a high-temperature matrix (over 300°C), which was the subject of the study, was described. The results of non-destructive testing (ultrasonic method) of thermoplastic panel were presented and conclusions were drawn.

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