Analyzing Deformation and Fracture of Dielectrics by Integral Characteristics of their Electromagnetic Emission

2016 ◽  
Vol 683 ◽  
pp. 36-43 ◽  
Author(s):  
Ludmila Yavorovich ◽  
Anatoly Bespal’ko ◽  
Pavel Fedotov ◽  
Aleksey Popelyaev
Keyword(s):  
Strain State ◽  
Electromagnetic Emission ◽  
High Strength ◽  
Dielectric Materials ◽  
Stress Strain ◽  
Rock Samples ◽  
Stress Strain State ◽  
Local Strength ◽  
Deformation And Fracture ◽  
Integral Characteristics

Revealing of fracture harbingers of dielectric materials, that are under mechanical stress, is an important practical and scientific problem. Local stresses, produced by mechanical impact, can exceed the local strength, and a stress-strain state changes. As the result of such impacts, microcracks appear and lead to fracture. During change of stress-strain state, mechanoelectric transformations occur, that generate electromagnetic emission. So we aimed to observe regularities in electromagnetic emission characteristics. Rock samples, collected from Tashtagol ore-mine of Kemerovo region of Russia, were used as dielectric materials for the research. For analysis of rock samples deformation and fracture, integral characteristics of time series of electromagnetic emission were used. Observed, that low-strength samples accumulate and relax elastic energy stepwise unlike to high-strength samples, that accumulate energy linearizely. Differences in dispersion characteristics of samples differing with strength are observed. The research showed usability of suggested algorithms.

Criterion for Controlling the Stress-Strain State of Composite Dielectric Materials Using the Effective Filtration Method

2018 ◽  
Vol 781 ◽  
pp. 108-113
Author(s):  
Vladimir Surzhikov ◽  
Pavel Fedotov
Keyword(s):  
Strain State ◽  
Dielectric Materials ◽  
Mirror Image ◽  
Electromagnetic Response ◽  
Stress Strain ◽  
Coherent Signal ◽  
Filtration Method ◽  
Stress Strain State ◽  
Left And Right ◽  
Sand Filler

The paper presents a brief description of a process of an electromagnetic response generation from dielectric composite materials when they are subjected to an acoustic impulses, a recording method by capacitive receivers and criteria for controlling the stress-strain state (SSS) for this method. Also there are the results of studies of the applicability of the effective filtration method for the control of similar products from epoxy resin with sand filler. The formation of a response with a pronounced maximum and an excitation pulse symmetric with respect to the end time is determined when a coherent signal is input to the input of the system, which is a mirror image of the impulse response. The correlation coefficient between the left and right parts of the response was chosen as a criterion for controlling the SSS.

scholarly journals Force control in girder-cable systems

2021 ◽  
Vol 7 (4) ◽  
pp. 5-13
Author(s):  
Gleb A. Averchenko ◽  
Kirill A. Vasilev ◽  
Elena A. Rudakova ◽  
Anastasiya I. Shashko ◽  
Vyacheslav A. Borisov
Keyword(s):  
Strain State ◽  
High Strength ◽  
Dynamic Programming Method ◽  
Structural Elements ◽  
Stress Strain ◽  
Optimal Sequence ◽  
Stress Strain State ◽  
The Matrix ◽  
Cable Systems ◽  
Bridge Spans

The object of the study is the forces in the beam-cable systems. The introduction of these systems in construction is associated with the task of creating a pre-stress in order to regulate the stress-strain state of the beam-cable system as a whole. Prestressing will make it possible to rationally use high-strength materials in the structure, and to design the structure economically. When designing girder-cable-stayed structures of bridge spans, it is necessary to determine the sequence of stresses of the structural elements-shrouds in order to regulate the forces in the beam element of the structure. This problem is considered in this article. The dynamic programming method is used to regulate the stress-strain state of the system by pulling the shrouds in the optimal sequence. To solve the problems, formulas for the output value and the optimality criterion, as well as the matrix, are given. As a result, the values of the output values of interest at all stages of the tension of the shrouds are found.

scholarly journals Computer simulation of deformation and fracture conditions during the detail rolling with a flange with inclined rolls

2021 ◽  
Vol 41 (2) ◽  
Author(s):  
Sergey A. Ignatiev ◽  
Pavel V. Kononov ◽  
Dmitry S. Levashov ◽  
Eduard Kh. Muratbakeev ◽  
Konstantin O. Glazunov
Keyword(s):  
Computer Simulation ◽  
Rheological Properties ◽  
Computer Model ◽  
Software Package ◽  
Strain State ◽  
Fracture Criterion ◽  
Stress Strain ◽  
Stress Strain State ◽  
Deformation And Fracture ◽  
Deform 3D

An adequate computer model of the process of rolling flange details with inclined rolls has been built in the software package DEFORM-3D. The analysis of the stress-strain state of a detail with a flange was performed. The rheological properties of the alloy L63 (62-65% Cu, 34.5-38% Zn) were experimentally studied. Value limits of the Cockcroft-Latham fracture criterion for the alloy L63 are determined.

On a criterion for testing the stress-strain state of dielectric materials

2017 ◽  
Vol 53 (3) ◽  
pp. 213-219
Author(s):  
V. P. Surzhikov ◽  
N. N. Khorsov ◽  
A. A. Demikhova
Keyword(s):  
Strain State ◽  
Dielectric Materials ◽  
Stress Strain ◽  
Stress Strain State

scholarly journals Accounting for the flexibility of nodes in the design of steel mesh dome

2018 ◽  
Vol 245 ◽  
pp. 08006
Author(s):  
Egor Kanaev ◽  
Daria Demidova ◽  
Sergey Zimin
Keyword(s):  
Strain State ◽  
High Strength ◽  
Stress Strain ◽  
Strain Capacity ◽  
Stress Strain State ◽  
Semirigid Connections ◽  
Different Types ◽  
Internal Forces ◽  
The City ◽  
Geodesic Dome

This paper presents the results of a study of the stress-strain state of a geodesic dome covering the planetarium designed in the city of Nizhny Novgorod. Four design schemes were created in the SCAD with different types of node modeling. A comparative analysis of the effect of the strain capacity of the “BrGTU” type unit on the stress-strain state of the dome cover has been carried out. The results are obtained on the change in the displacements of the structure nodes and internal forces in the dome bars, with rigid and hinged mates. The option of increasing the diameter of high-strength bolts to reduce the overall deformability of the system is considered. On the basis of the obtained results, it was concluded that it is necessary to take into account the strain capacity of the semirigid connections when designing mesh steel domes.

Electromagnetic Methods for Testing Changes in Stress-Strain State of Dielectric Materials

2021 ◽  
Vol 57 (10) ◽  
pp. 865-876
Author(s):  
A. A. Bespal’ko ◽  
D. D. Dann ◽  
M. V. Petrov ◽  
E. K. Pomishin ◽  
G. E. Utsin ◽  
...  
Keyword(s):  
Strain State ◽  
Dielectric Materials ◽  
Stress Strain ◽  
Stress Strain State ◽  
Electromagnetic Methods

Comparison of Stress-Strain States of Rail-Wheel Pair Made of Steel and MoNiCa

2021 ◽  
Vol 320 ◽  
pp. 14-19
Author(s):  
Sergei Sherbakov ◽  
Aliaksandr Bahdanovich ◽  
Aleh Nasan ◽  
Daria Podgayskaya ◽  
Liudmila Shemet ◽  
...  
Keyword(s):  
Strain State ◽  
Rail Steel ◽  
Three Dimensional ◽  
High Strength ◽  
Bottom Surface ◽  
Stress Strain ◽  
Wheel Pair ◽  
Stress Strain State ◽  
Freight Car ◽  
Von Mises

Contact interaction in a wheel-rail pair and its corresponding stress-strain state for various combinations of materials of this pair and the weights of passenger and freight cars were considered. The materials under study were steel and high-strength cast iron based structural material MoNiCa with strength and wear-fatigue characteristics close to steel ones.The load on each wheel was: 53.9 and 294.3 kN for an empty and loaded freight car, 146.8 kN and 230.5 kN for an empty and loaded passenger car. The bottom surface of the rail was rigidly fixed.Young's modules were adopted as follows: 200 GPa for steel and 165 for MoNiCa. The results of finite element calculations of the three-dimensional stress-strain state showed that the largest von Mises stresses of 613.08 MPa occur in the wheel (steel)-rail (steel) pair of the loaded freight car. For all types of loading, the lowest stresses (15.8 % – 16.7 % less than in the steel-steel pair) are observed in the wheel (MoNiCa)-rail (MoNiCa) pair. This indicates the appropriateness of using MoNiCa for the manufacturing elements of the wheel-rail system.

The Application of Reverberation in Method of Mechanoelectrical Transformations for Estimation of Stress-Strain State in Solid Dielectrical Matter

2019 ◽  
Vol 970 ◽  
pp. 47-54
Author(s):  
Petr Khorsov ◽  
Roman Laas ◽  
Anatoly P. Surzhikov
Keyword(s):  
Statistical Analysis ◽  
Acoustic Waves ◽  
Strain State ◽  
Mechanical Load ◽  
Dielectric Materials ◽  
Random Component ◽  
Differential Analysis ◽  
Stress Strain ◽  
Stress Strain State ◽  
Mechanoelectrical Transformations

The paper assesses the possibility of using the reverberation phenomenon to control the imperfections and the stress-strain state of solid dielectric materials by the method of mechanoelectrical transformations. The main advantage of reverberation is the repeated intersections of the excitation zones of inhomogeneities by acoustic waves, that is displayed in response parameters. The reverberation makes it possible to accumulate distortions of wave fronts. A comparative analysis of the responses from the sample under condition of uniaxial compression under different loads was performed. Differential analysis for the deterministic time component of the response in the interval (0–0.3) ms, and a statistical analysis of the differences for the pseudo-random component in the interval (0.8–1.8) ms were performed. For the statistical analysis, the distribution of the pulse flow is selected. The response was calculated according to the mathematical model under the conditions of a change in the speed of sound, which simulates a change in the sample inhomogeneity under load. The calculation showed a qualitative similarity with changes in responses in a real experiment. According to the obtained results, it was concluded that it is possible to use the deterministic and pseudo-random components of the responses in the reverberation condition to control the change in defectiveness and the degree of heterogeneity under the action of the mechanical load on the sample.

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