Changes in the Parameters of the Electromagnetic Response of Model Dielectric Samples with Air Cavity Defects under External Deterministic Acoustic Impact

2021 ◽  
Vol 101 (1) ◽  
pp. 12-17
Author(s):  
D.D. Dann ◽  
◽  
M.V. Petrov ◽  
P.I. Fedotov ◽  
E.A. Sheveleva ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Dielectric Materials ◽  
Electromagnetic Response ◽  
Average Weight ◽  
Acoustic Excitation ◽  
Ball Impact ◽  
Electromagnetic Signals ◽  
Air Cavities ◽  
The Impact

The paper discusses the possibility of testing the air inclusions saturation in cement-sand samples using the acoustic-electrical transformations phenomenon in heterogeneous dielectric materials. An experiment technique is presented including contact external acoustic excitation and contactless registration of the electromagnetic response to such an impact. Methods of samples deterministic acoustic excitation by a ball impact and the experimental determination of the impact energy are described. The model samples size and composition are described, including air cavities in a polyethylene sheath. The experimental studies geometry is shown, indicating the direction of the samples acoustic excitation and the location of the electromagnetic receiving plates. It is shown that the defect-free samples and with air cavities, have different amplitude and frequency of the electromagnetic signals spectral components. The samples with air cavities have the average weight of the EMS spectrum changes towards lower frequencies. This frequency shift effectively reflects the concentration of air cavities defects in a cement-sand samples and this effect can be used when testing concrete products for the presence of air inclusions, and, accordingly, will allow determining the frost resistance of products.

scholarly journals The results of experimental studies of VLF–ULF electromagnetic emission by rock samples due to mechanical action

2013 ◽  
Vol 1 (6) ◽  
pp. 7821-7842
Author(s):  
A. A. Panfilov
Keyword(s):  
Laboratory Experiments ◽  
Experimental Studies ◽  
Electromagnetic Emission ◽  
Mechanical Action ◽  
Frequency Range ◽  
Impact Action ◽  
Rock Samples ◽  
Electric Component ◽  
Electromagnetic Signals ◽  
The Impact

Abstract. The paper presents the results of laboratory experiments on electromagnetic emission excitation (electric component of electromagnetic field) by rock samples due to different forms of mechanical stress applications. It was shown that samples generate electric impulses with different spectra when the impact action, gradual loading or dynamic friction is applied. It was ascertained that level and spectral compositions of signals, generated by rock samples, change with increasing quantity of hits. It was found that strong electromagnetic signals, generated while rock samples were fracturing, were accompanied by repetitive weak, but perceptible variations of the electric field intensity in short frequency range.

scholarly journals Material and Structural Modeling Aspects of Brain Tissue Deformation under Dynamic Loads

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 271 ◽  
Author(s):  
Monika Ratajczak ◽  
Mariusz Ptak ◽  
Leszek Chybowski ◽  
Katarzyna Gawdzińska ◽  
Romuald Będziński
Keyword(s):  
Brain Tissue ◽  
Human Subjects ◽  
Experimental Studies ◽  
Material Modeling ◽  
Geometrical Parameters ◽  
Dynamic Loading Conditions ◽  
Technological Improvements ◽  
The Impact ◽  
The Brain

The aim of this work was to assess the numerous approaches to structural and material modeling of brain tissue under dynamic loading conditions. The current technological improvements in material modeling have led to various approaches described in the literature. However, the methods used for the determination of the brain’s characteristics have not always been stated or clearly defined and material data are even more scattered. Thus, the research described in this paper explicitly underlines directions for the development of numerical brain models. An important element of this research is the development of a numerical model of the brain based on medical imaging methods. This approach allowed the authors to assess the changes in the mechanical and geometrical parameters of brain tissue caused by the impact of mechanical loads. The developed model was verified through comparison with experimental studies on post-mortem human subjects described in the literature, as well as through numerical tests. Based on the current research, the authors identified important aspects of the modeling of brain tissue that influence the assessment of the actual biomechanical response of the brain for dynamic analyses.

EXPERIMENTAL AND NUMERICAL INVESTIGATION ON MANUFACTURING METHODS OF POWDER METALLURGY COMPONENTS WITH INTEGRATED INFORMATION STORAGE

2011 ◽  
Vol 10 (01) ◽  
pp. 11-20
Author(s):  
BERND-ARNO BEHRENS ◽  
NAJMEH VAHED ◽  
EDIN GASTAN ◽  
FABIAN LANGE
Keyword(s):  
Research Work ◽  
Experimental Studies ◽  
Information Storage ◽  
Research Centre ◽  
Specific Data ◽  
Data Carrier ◽  
Foreign Materials ◽  
The Impact ◽  
Sintering Processes

This paper presents a research work within Collaborative Research Centre 653 "Gentelligent Components in Their Lifecycle." The term "gentelligent" refers to the genetic and intelligent character of these components. Specific data are inherently saved in the components, which are used during its lifecycle for the means of identification, processing, and reproduction. The present study aims at the development of a method to manufacture and utilize gentelligent sintered parts. As data carrier, foreign materials shaped in fonts, logos, or codes are embedded in the powder material proceeded by pressing and sintering processes. The foreign material can be applied in forms of particles or compound powder. The information read-out is based on radiographic methods. The objectives of the investigations are the determination of the process parameters of each method and the impact of the integrated foreign materials on the mechanical properties of the component. The experimental studies are supported by numerical simulations.

scholarly journals Experimental research of the air permeability of concrete in the compressed zone of the containment for power units no. 1, 2 of the South-Ukrainian NPP

2021 ◽  
Vol 20 ◽  
pp. 39-50
Author(s):  
Ia. A. Zhygalov ◽  
◽  
V. V. Inyushev ◽  
V. O. Posokh ◽  
S. A. Vyzhva ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Air Permeability ◽  
Complex Stress State ◽  
Air Pressure ◽  
Design Basis ◽  
Design Basis Accident ◽  
The Impact ◽  
Experimental Researches ◽  
Maximum Design

The determination of the air permeability of concrete in the compressed zone of NPP’s containment under conditions of excessive air pressure in the subshell space of the reactor compartment under a maximum design basis accident is necessary to confirm the localizing functions of the containment when extending the lifetime of power units. Approaches to determining the localizing ability (air permeability) of concrete in the compressed zone of the containment of NPPs with WWER-1000 type reactors under the impact of excessive air pressure under conditions of maximum design basis accident are discussed in the article. The designed testing installation for experimental studies of the air permeability of concrete by the method of stationary radial filtration is described and the results of experimental researches of the air permeability on the installation are presented for samples simulating the composition of concrete used under construction of the containment for Power Units No. 1, 2 (series B-302 and B-338, respectively) SD “South-Ukrainian NPP”. A comparative analysis of the results of abovementioned experimental researches with the results of experimental and theoretical work on the study of air permeability of the similar samples-imitators of concrete by the method of stationary linear filtration, as well as the results of measurements for samples of concrete sampled directly from the compressed zone of containment for Power Unit No. 2 of SD “South-Ukrainian NPP” was fulfilled. The results are explained by processes of compaction of the concrete structure under a complex stress state that occurs under specific hardening conditions and during longtime compression by pre-stressed reinforcing ropes, which takes place under conditions of real containment operation. It was concluded that the simulators made according to the currently accepted technology cannot provide a correct determination of the localizing ability of the NPP’s containment, since the conditions and time of containment concrete hardening, as well as the longtime constant compressive action of reinforcing ropes, cannot be correctly modeled in full under the formation of samples-imitators. The issue of the containment concrete samplesimitators creating in laboratory conditions requires additional study, improvement of technology and the development of new approaches with maximum physical modeling of the conditions characteristic of the operation of the NPP containment.

Электромагнитные методы контроля изменений напряженно-деформированного состояния диэлектрических материалов

2021 ◽  
pp. 44-53
Author(s):  
А.А. Беспалько ◽  
Д.Д. Данн ◽  
М.В. Петров ◽  
Е.К. Помишин ◽  
Г.Е. Уцын ◽  
...  
Keyword(s):  
Strain State ◽  
Experimental Studies ◽  
Electromagnetic Emission ◽  
Acoustic Excitation ◽  
Acoustic Sounding ◽  
Rock Samples ◽  
Electromagnetic Responses ◽  
Electromagnetic Signals ◽  
Complex Methods ◽  
Sample Axis

Mechanical-electrical and acoustic-electrical complex methods of testing cracking while changing the stress-strain state in dielectrics are discussed on the example of rock samples. The paper discusses the results of numerical and experimental studies of changes in the electromagnetic responses parameters under the pulse deterministic acoustic excitation of rock samples with different composition and texture. Also the results of mathematical calculations of the stress concentration on cracks located along the sample axis are presented, perpendicular to which deterministic acoustic pulses were introduced. The experimental studies results of sample electromagnetic emission with containing calcite and magnetite under uniaxial compression to fracture are shown. Regularities in the electromagnetic signals amplitudes changes during acoustic sounding in the process of «stepwise» uniaxial loading by compression to destruction are given.

Manufacturing Method of PM Components with Integrated Information Storage

2010 ◽  
Vol 44-47 ◽  
pp. 915-919 ◽  
Author(s):  
Bernd Arno Behrens ◽  
Najmeh Vahed ◽  
Edin Gastan ◽  
Fabian Lange
Keyword(s):  
Research Work ◽  
Experimental Studies ◽  
Information Storage ◽  
Research Centre ◽  
Specific Data ◽  
Manufacturing Method ◽  
Foreign Materials ◽  
The Impact ◽  
Sintering Processes

This paper presents a research work within Collaborative Research Centre 653 “Gentelligent Components in Their Lifecycle”. The term “gentelligent” refers to the genetic and intelligent character of these components. Specific data are inherently saved in the components which are used during its lifecycle for the means of identification, processing and reproduction. The presented study aims for the development of a method to manufacture and utilize gentelligent sintered parts. As data carrier, foreign materials shaped in fonts, logos or codes, are embedded in the powder material proceeded by pressing and sintering processes. The foreign material can be applied in forms of particles or compound powder. The information read-out is based on radiographic methods. The objectives of the investigations are the determination of the process parameters of each method and the impact of the integrated foreign materials on the mechanical properties of the component. The experimental studies are supported by numerical simulations.

scholarly journals Transport phenomena in complex systems (part 1)

2021 ◽  
Vol 379 (2205) ◽  
pp. 20200301
Author(s):  
Dmitri V. Alexandrov ◽  
Andrey Yu Zubarev
Keyword(s):  
Complex Systems ◽  
Blood Vessels ◽  
Transport Phenomena ◽  
Experimental Studies ◽  
Computational Modelling ◽  
Biological Tissues ◽  
Transport Processes ◽  
Nonlinear Transport ◽  
The Impact

The issue, in two parts, is devoted to theoretical, computational and experimental studies of transport phenomena in various complex systems (in porous and composite media; systems with physical and chemical reactions and phase and structural transformations; in biological tissues and materials). Various types of these phenomena (heat and mass transfer; hydrodynamic and rheological effects; electromagnetic field propagation) are considered. Anomalous, relaxation and nonlinear transport, as well as transport induced by the impact of external fields and noise, is the focus of this issue. Modern methods of computational modelling, statistical physics and hydrodynamics, nonlinear dynamics and experimental methods are presented and discussed. Special attention is paid to transport phenomena in biological systems (such as haemodynamics in stenosed and thrombosed blood vessels magneto-induced heat generation and propagation in biological tissues, and anomalous transport in living cells) and to the development of a scientific background for progressive methods in cancer, heart attack and insult therapy (magnetic hyperthermia for cancer therapy, magnetically induced circulation flow in thrombosed blood vessels and non-contact determination of the local rate of blood flow in coronary arteries). The present issue includes works on the phenomenological study of transport processes, the derivation of a macroscopic governing equation on the basis of the analysis of a complicated internal reaction and the microscopic determination of macroscopic characteristics of the studied systems. This article is part of the theme issue ‘Transport phenomena in complex systems (part 1)’.

scholarly journals The results of experimental studies of VLF–ULF electromagnetic emission by rock samples due to mechanical action

2014 ◽  
Vol 14 (6) ◽  
pp. 1383-1389 ◽  
Author(s):  
A. A. Panfilov
Keyword(s):  
Laboratory Experiments ◽  
Experimental Studies ◽  
Electromagnetic Emission ◽  
Mechanical Action ◽  
Impact Action ◽  
Rock Samples ◽  
Electric Component ◽  
Electromagnetic Emissions ◽  
Electromagnetic Signals ◽  
The Impact

Abstract. The paper presents the results of laboratory experiments on electromagnetic emissions excitation (the electric component of electromagnetic fields) by rock samples due to different forms of mechanical stress applications. It was shown that samples generate electric impulses with different spectra when the impact action, gradual loading or dynamic friction is applied. It was ascertained that level and spectral compositions of signals, generated by rock samples, change with an increasing number of hits. It was found that strong electromagnetic signals, generated while rock samples were fracturing, were accompanied by repetitive weak but perceptible variations in the electric field intensity in short frequency ranges.

Acoustic-electrical testing of defects in the cement-sand and cement-glass model samples

2021 ◽  
Vol 103 (3) ◽  
pp. 6-16
Author(s):  
A.A. Bespalko ◽  
◽  
D.D. Dann ◽  
M.V. Petrov ◽  
E.K. Pomishin ◽  
...  
Keyword(s):  
Electrical Resistance ◽  
Acoustic Pulse ◽  
Specific Electrical Resistance ◽  
Double Layers ◽  
Electromagnetic Response ◽  
Electromagnetic Signal ◽  
Complex Method ◽  
Acoustic Excitation ◽  
Glass Model ◽  
The Impact

A complex method of acoustic-electrical testing of defects in dielectric samples made from cement-sand and cement-glass mixtures is discussed. The paper reports the results of studies of changes in the parameters of electromagnetic responses and their spectra under pulsed deterministic acoustic excitation of model samples with defects in the form of solid-state inclusions. The results of mathematical calculations of the time variation in the stress-strain state induced in a defective dielectric model sample by deterministic acoustic pulse are presented. The relationship is shown between the parameters of the acoustic excitation and the electromagnetic response to the impact in a magnetic field. The study revealed that the specific electrical resistance of the cement-sand and cement-glass mixtures differs significantly. Excitation of electrical double layers by acoustic pulses causes an electromagnetic signal, parameters of which depend on the parameters of the acoustic impact and acoustic and electrical properties of the material. As a result, a reduced specific electrical resistance of the mixture increases its conductivity. The numerical calculation of the propagation of the deterministic acoustic pulse showed that its parameters change when it passes through a defect with acoustic impedance different from that of the mixture used.

THE METHOD OF DETERMINING THE PUNCHING ACTION OF THE READY-MADE DAMAGE ELEMENT OF FRAGMENTATION OF HIGH-EXPLOSIVE WARHEAD

2019 ◽  
Vol 1 (12) ◽  
pp. 41-47
Author(s):  
O. Obukhov ◽  
S. Usenko
Keyword(s):  
High Explosive ◽  
Experimental Studies ◽  
Limited Range ◽  
Software Complex ◽  
Penetration Ability ◽  
The Subject ◽  
Cruise Missiles ◽  
The Cost ◽  
The Impact

The subject of this article is the development of a method for determining the penetration capacity of ready-made elements of damage to a fragmentation and high-explosive warhead. The analysis of the existing methods of determining the penetration capacity of the damage elements indicates their inconsistency with the modern requirements for determining the power of means of destruction of combat parts of missiles, tactical and cruise missiles and aircraft bombs. Existing techniques that were proposed in the late 19th and early 20th centuries are based on the systematization of empirical research and are outdated and have a limited range of applications. Since they do not take into account the zone of contact interacting between the element of the impact and the obstacle and the critical angle of approach, which will determine the ricochet conditions. The article presents the results of the calculated determination of the penetration capacity of the ready-made damage element, taking into account the contact surface of the interaction of the damage element with the obstacle, which are obtained as a result of the calculation modelling in the Ansys Autodyn software complex. Ways to determine the penetration capacity of ready-made destruction elements of fragmentation and high-explosive warhead, taking into account their true geometric shape and excess kinetic energy are proposed in the article. The proposed technique can be used to create the penetration nomograms of the elements of the lesion. The application of computational modeling of the determination of nonograms of penetration ability will allow to abandon a large number of experimental studies with real undermining of the warhead, thereby reducing the cost and speeding up the process of creating, refining and adopting the newest samples of defeat equipment.

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