scholarly journals Rating of the limiting state of 20K steel under low-cycle loading using the using the method of LM-hardness

2021 ◽  
Author(s):  
P. Bulakh ◽  
Volodymyr Shvets ◽  
О. Maslo
Keyword(s):  
Residual Life ◽  
Structural Elements ◽  
Structural Element ◽  
Limiting State ◽  
Current State ◽  
Scattered Damage ◽  
Cycle Loading ◽  
Non Destructive ◽  
Degree Of Degradation ◽  
Methods Of Control

In the express diagnostics of the condition of the material of the elements of the structures in operation and the materials for the manufacture of the responsible elements of the equipment, it is necessary to take into account the current damage. At the same time, non-destructive methods of control are more relevant, which allow to assess the level of scattered damage in the material and the degree of degradation of its structure of the metal. Another important factor in controlling the current state of the material is the assessment of the residual life of the structural element under operating loads. This paper presents the results of research on the application of the non-destructive method of LM-hardness in assessing the characteristics of the limiting state of the material of real structural elements operating under low-cycle load.

Probabilistic forecasting of durability and residual life of structural elements

2020 ◽  
pp. 39-40
Author(s):  
A.S. Gusev ◽  
S.A. Starodubtseva ◽  
V.I. Scherbakov
Keyword(s):  
Failure Analysis ◽  
Residual Life ◽  
Initial Time ◽  
Time Interval ◽  
Structural Elements ◽  
Probabilistic Forecasting ◽  
Structural Element

The method of computational forecasting of durability and residual life of structural elements based on the results of failure analysis at a small initial time interval of their operation is proposed. Keywords forecasting, durability, residual life, failure, structural element, reliability [email protected]

State and Prospective Directions of Development of Methods of Control of Raw Materials Packed in Sealed Containers

ANRI ◽  
2021 ◽  
Vol 0 (3) ◽  
pp. 3-14
Author(s):  
Valeriy Dreyzin ◽  
Artyem Sviridov ◽  
Vyacheslav Varganov ◽  
Dmitriy Logvinov
Keyword(s):  
Coming Out ◽  
Raw Materials ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Vector Method ◽  
Current State ◽  
Further Development ◽  
Non Destructive ◽  
Methods Of Control

The current state of non-destructive testing of radioactive waste (RW) packed in sealed containers by the energy spectrum of gamma radiation coming out of the container is considered. A brief analysis of the methods used in existing installations for the control and certification of containers with RW for conducting nuclide analysis of RW with the determination of the specific activities of the radionuclides contained in them is carried out, and their shortcomings are shown. More effective methods of RW characterization are proposed: the problems of controlling hard – to-detect radionuclides (alpha-and beta-emitting nuclides) and the disadvantages of the “scaling coefficients”method recommended by MAGATE for their control are considered. More promising methods are proposed, which are a further development of the”nuclide vector method”. The list of “reference” gamma-emitting nuclides used in their implementation is justified.

Materials Diagnostics: Non-Destructive Identification of Degraded Areas of Microstructure

2014 ◽  
Vol 223 ◽  
pp. 348-354
Author(s):  
Jan T. Bonarski
Keyword(s):  
Functional Materials ◽  
Structural Elements ◽  
Structural Element ◽  
Experimental Conditions ◽  
Near Surface ◽  
Materials Engineering ◽  
Laboratory Techniques ◽  
Wide Range ◽  
Challenging Research ◽  
Non Destructive

The influence of material anisotropy on the exploitation performance of structural elements is recognized still insufficiently. The state seems to be the more evident if we consider that each type of materials inhomogeneity is not neutral in relation to its properties. In this field, carefully selected characteristics – the kind of microstructure diagnostics – delivers valuable data for the identification and quantification of desired material parameters deciding its usability. A separate problem is a spatial distribution of the parameters, which is an important feature of advanced, multi-functional materials with gradient-or/and layered structure. Further stages of the microstructure diagnostics covering the prediction of material behaviour in exploitation conditions and the estimation of the time of safe exploitation are still challenging research problems.The enumerated aspects of materials diagnostics require experimental data registered for the representative sample and suitable methods of data processing. Laboratory techniques and modelling procedures utilized in contemporary materials engineering deliver a wide range of computer-aided methodology, enabling one to obtain valuable characteristics of material, including crystallographic texture, residual stresses, phase composition, and crystallite size. In addition to methodological, experimental conditions play an important role in the outlined microstructure diagnostics. Both aspects are evident in the case of the identification of a subtle field of stresses resisted in the near-surface layer or in coating-substrate interface where a non-destructive way of examination is demanded. This work presents a selected non-destructive investigation of degraded areas of materials, recognized as critical from the viewpoint of the behaviour of a specific structural element in exploitation conditions.

STRUCTURAL RELIABILITY ANALYSIS BASED ON P-BOXES

2020 ◽  
Vol 92 (6) ◽  
pp. 51-58
Author(s):  
S.A. SOLOVYEV ◽  
Keyword(s):  
Probability Distribution ◽  
Reliability Analysis ◽  
Structural Reliability ◽  
Epistemic Uncertainty ◽  
Random Variable ◽  
Strength Criterion ◽  
Structural Elements ◽  
Structural Element ◽  
Limit States ◽  
Distribution Shape

The article describes a method for reliability (probability of non-failure) analysis of structural elements based on p-boxes. An algorithm for constructing two p-blocks is shown. First p-box is used in the absence of information about the probability distribution shape of a random variable. Second p-box is used for a certain probability distribution function but with inaccurate (interval) function parameters. The algorithm for reliability analysis is presented on a numerical example of the reliability analysis for a flexural wooden beam by wood strength criterion. The result of the reliability analysis is an interval of the non-failure probability boundaries. Recommendations are given for narrowing the reliability boundaries which can reduce epistemic uncertainty. On the basis of the proposed approach, particular methods for reliability analysis for any structural elements can be developed. Design equations are given for a comprehensive assessment of the structural element reliability as a system taking into account all the criteria of limit states.

Vibration-Based Crack Detection in L-Frames

2014 ◽  
Vol 658 ◽  
pp. 261-268
Author(s):  
Jean Louis Ntakpe ◽  
Gilbert Rainer Gillich ◽  
Florian Muntean ◽  
Zeno Iosif Praisach ◽  
Peter Lorenz
Keyword(s):  
Strain Energy ◽  
Crack Detection ◽  
Natural Frequencies ◽  
Vibration Modes ◽  
Structural Elements ◽  
Element Analysis ◽  
Accurate Localization ◽  
Mathematical Expressions ◽  
Measurement Results ◽  
Non Destructive

This paper presents a novel non-destructive method to locate and size damages in frame structures, performed by examining and interpreting changes in measured vibration response. The method bases on a relation, prior contrived by the authors, between the strain energy distribution in the structure for the transversal vibration modes and the modal changes (in terms of natural frequencies) due to damage. Using this relation a damage location indicator DLI was derived, which permits to locate cracks in spatial structures. In this paper an L-frame is considered for proving the applicability of this method. First the mathematical expressions for the modes shapes and their derivatives were determined and simulation result compared with that obtained by finite element analysis. Afterwards patterns characterizing damage locations were derived and compared with measurement results on the real structure; the DLI permitted accurate localization of any crack placed in the two structural elements.

GENETIC METHODS OF INSECT CONTROL. HISTORY AND CURRENT STATE

2021 ◽  
Vol 14 (1) ◽  
pp. 51-63
Author(s):  
A. G. Viktorov
Keyword(s):  
Invasive Species ◽  
Natural Selection ◽  
Sterile Insect Technique ◽  
Genetically Engineered ◽  
Insect Control ◽  
Genetic Method ◽  
Recessive Mutations ◽  
Current State ◽  
Invasive Mosquito ◽  
Methods Of Control

The review considers the main stages in the development of genetic method of insect control: 1) The idea of A.S. Serebrovsky, who suggested releasing males with non-viable translocations into nature; 2) "Z-lethal" method of V.A. Strunnikov for control of harmful Lepidoptera, which consists in the release of males carrying two non-allelic recessive mutations in the sex Z-chromosomes into nature; 3) Sterile insect technique (SIT) used widely in practice in the second half of the XX-th century; 4) Genetically engineered biotechnology RIDL (Release of Insects carrying a Dominant Lethal) used in practice to control the invasive mosquito Aedes aegypti , the vector of Zika viruses and yellow fever. It is generalized that the main opponent of the genetic method of insect control is natural selection, which supports females, choosing natural rather than sterile or "genetically modified" males on mating. It follows from the above that genetic methods of control can be effective only in control of invasive species have not spread widely yet.

Some problems of assessing the dynamic crack resistance of structural steels

2021 ◽  
Vol 18 (3) ◽  
pp. 428-435
Author(s):  
Vladimir I. SMIRNOV ◽  
◽  
Tatiana A. KNOPOVA ◽  
Sergey S. MAYER ◽  
◽  
...  
Keyword(s):  
Crack Resistance ◽  
High Speed ◽  
Dynamic Testing ◽  
Practical Importance ◽  
Dynamic Strength ◽  
Structural Steels ◽  
Dynamic Crack ◽  
Unstable Fracture ◽  
Structural Elements ◽  
Limiting State

Objective: Solving the problem of determining the conditions for the onset and development of unstable fracture, which is extremely important for the development of methods for calculating the limiting states of structural elements, improving the dynamic testing schemes of materials and classifying steels according to their ability to resist fracture. Methods: Analytical methods for assessing the limiting state of structural elements are used. Results: A brief overview of the available test methods for structural steels for dynamic strength and crack resistance is given. The experience accumulated by domestic and foreign practices in testing steels for strength and crack resistance under high-speed loading is analyzed. The disadvantages of the existing methods for assessing the indicators of dynamic strength and resistance to brittle fracture are indicated. Practical importance: It is shown that along with the traditional methods for assessing strength based on safety factors, it is necessary to develop and apply new methods for assessing the limiting state of structural elements, including by the criteria of crack resistance

Study of the residual imperfections using methods of probability theory

2021 ◽  
Vol 87 (9) ◽  
pp. 44-49
Author(s):  
D. A. Kuzmin
Keyword(s):  
Probability Theory ◽  
Generalized Equation ◽  
Structural Elements ◽  
Non Destructive Testing ◽  
Operational Control ◽  
Destructive Testing ◽  
Control Procedures ◽  
Non Destructive ◽  
A Current

Discontinuities in the products that occur during manufacture, mounting or upon operation can be missed during non-destructive testing which do not provide their complete detectability at a current level of the technology. Therefore, it is necessary to take into account that certain structural elements may have discontinuities of significant dimensions. We present the results of using the methods of probability theory in studying the residual imperfections that remains in the structure after non-destructive control and repair of the previously identified defects. We used the results of operational control of units carried out by ultrasonic and radiographic methods. We present a method for determining a multifactorial coefficient that takes into account the detectability of defects, the number of control procedures and the errors in the instrumentation and methodological support, as well as a generalized equation for the probability distribution of detecting discontinuities. The developed approach provides assessing of the level of damage to the studied objects, their classification proceeding from the quantitative data and determination of the values of postulated discontinuities for deterministic calculations. The results obtained can be used to improve the methods of monitoring NPP facilities.

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