scholarly journals On the development of mathematical models for the reliability evaluation of aircraft operation in combat conditions

2021 ◽  
Vol 13 (S) ◽  
pp. 169-178
Author(s):  
Ihor S. ROMANCHENKO ◽  
Oleh SEMENENKO ◽  
Maryna SLIUSARENKO ◽  
Mykola VASIANOVYCH ◽  
Ihor LEVCHENKO
Keyword(s):  
Mathematical Models ◽  
Rational Design ◽  
Methodological Approach ◽  
Operating Time ◽  
Reliability Evaluation ◽  
Time To Failure ◽  
Significant Discrepancy ◽  
Reliability Indicators ◽  
Technical Specifications ◽  
Cost Of Time

The authors of this study propose a methodological approach to modelling the reliability evaluation of aircraft operation in combat conditions. When developing recommendations on operational and strategic requirements for promising aircraft, a very important aspect is the elicitation of the requirements for their reliability, namely no-failure operation. Reliability as a parameter of any equipment should be set in the technical specifications for development together with other operational requirements in the form of reasonable quantitative indicators – reliability standards. The establishment of specific reliability standards stimulates its growth and creates the basis for rational design, taking into account the requirements of reliable operation. The analysis showed that different models can be used to simulate aircraft reliability. In this case, for example, the final values of mean time to failure (MTTF) would be different. The test results show that the methods and mathematical models used to substantiate the values of time and probability of trouble-free operation of aircraft do not fully correspond to the actual processes of changing their state during the use in the military. This is confirmed by a significant discrepancy in the values of reliability indicators implemented in practice. This was due to the fact that the acquainted mathematical models of aircraft reliability do not take into account the combat conditions in which they are supposed to operate. In addition, the reliability indicators used do not take into account possible changes (decrease) in these indicators during the period of aircraft operation. In general, the shortcomings inherent in the methods and mathematical models currently used to describe the aircraft reliability reduce the accuracy of the results obtained, and also do not quite adequately reflect the features of the corresponding process. When using different models, the cost of time to failure differs significantly. The more factors are taken into account, the greater the operating time to failure will be. This means that when designing aircraft, it is necessary to set the value of this indicator greater than indicated in the form. Taking into account additional factors complicates the model, but at the same time makes it more accurate.

scholarly journals A formalized representation of exponential models of the main indicators of reliability, the limitations of their use for the characteristics of engineering weapons

2021 ◽  
Vol 12 (2) ◽  
pp. 100-105
Author(s):  
Andriy Poliakov ◽  
◽  
Volodymyr Kryvtsun ◽  
Maksym Kalenyk ◽  
Viacheslav Nagachevskyi ◽  
...  
Keyword(s):  
Operating Time ◽  
Experimental Studies ◽  
Aviation Industry ◽  
Time To Failure ◽  
Exponential Models ◽  
Air Defense ◽  
Engineering Equipment ◽  
Reliability Indicators ◽  
Real Process ◽  
State Of Affairs

The article deals with the solution of a scientific and applied problem to study the possibility of using existing exponential models to determine the reliability indicators of engineering weapons. Exponential models are widely used to assess the reliability of objects, mainly consisting of radio electronic elements, which led to their mass distribution in the aviation industry, air defense facilities, etc. Experimental operation of typical samples of military road-building equipment and experimental studies of the operating time of the main blocks and assemblies of engineering weapons show that the rate of failure and restoration of these products are functions of time. This state of affairs is associated with the design features of engineering weapons, which are characterized by the complex use of electrical, mechanical, hydraulic and other systems, while during use these systems can often experience significant overloads. At the same time, it should be borne in mind that today the engineering weapons that are in the units generally have a service life longer than that guaranteed by the manufacturer, which significantly affects the parameters of failure rates and recovery. The article shows the procedure for obtaining expressions for calculating the main indicators of the reliability of complex technical systems with an exponential distribution of operating time to failure and their recovery time and it is allowed to use them only for minimal periods of time (from several hours to several days, depending on the intensity of the use of machines) due to for the non-ergodic nature of the process of failures and restorations. In addition, the use of these models should be accompanied by an assessment of the adequacy of the results obtained to the real process with the adjustment of the duration of the corresponding time intervals. Thus, the construction of mathematical models of the technical state of engineering equipment will be accompanied by a search for other conceptual approaches to determining the reliability indicators of engineering equipment and methods for calculating these indicators.

ASSESSMENT OF THE RELIABILITY OF VACUUM PRECISION PIEZOELECTRIC RESONATORS ACCORDING TO THE RESULTS OF THE ACCUMULATION AND COMPILATION OF THEIR LIFE CYCLE

2018 ◽  
pp. 65-71 ◽  
Author(s):  
I. V. Arkhipova
Keyword(s):  
Life Cycle ◽  
Reliability Theory ◽  
Time To Failure ◽  
Bayesian Theorem ◽  
Piezoelectric Resonators ◽  
Reliability Indicators ◽  
Performance Requirements ◽  
Methodical Basis ◽  
New Ideas ◽  
Generalization Of Data

Within the framework of this article the question of reliability evaluation of resonators with strict performance requirements for resistance to external factors is considered. Due to the increase in requirements for these products in terms of gamma-percentile time to failure and gamma-percentile storageability time, there is a need to develop new ideas and methods of reliability theory. As a methodical basis for generalization of data of their life cycle the approach on the basis of Bayesian theorem is offered. Based on the results of generalization of the statistics of resonator tests for various types of climatic influences and reliability tests, as well as the results of their use in the electronic equipment have been identified their main reliability indicators.

Vibration Control in Industrial Plant: A Methodological Approach

1987 ◽  
Vol 109 (4) ◽  
pp. 335-342
Author(s):  
D. Miconi
Keyword(s):  
Mathematical Models ◽  
Vibration Control ◽  
Methodological Approach ◽  
Graphic Representation ◽  
Industrial Plant ◽  
Design Stage ◽  
Machine Foundation ◽  
Damping Characteristics ◽  
Effective Instrument

The present paper is a report on the construction of nomograms to ascertain the domain of elastic-inertial-damping characteristics required in vibrating machine-foundation systems, in order to ensure that ergonomic and other technical constraints are complied with. Nomograms, which are the graphic representation of mathematical models in nondimensional form, prove to be an effective instrument for orientation in the design stage.

Contribution to Rolling Bearing Reliability Modeling

2011 ◽  
Vol 110-116 ◽  
pp. 2497-2503 ◽  
Author(s):  
Zdenek Vintr ◽  
Michal Vintr
Keyword(s):  
Operating Time ◽  
Rolling Bearing ◽  
Time To Failure ◽  
Rolling Bearings ◽  
Mean Time To Failure ◽  
Reliability Modeling ◽  
Time Between Failures ◽  
Large Groups ◽  
Mean Time

Rolling bearings are usually considered to be non-repaired items the reliability of which is characterized by mean time to failure, or so called basic rating life. Reliability describes these parameters well in case the bearings are used in operation up to the very time the failure occurs, or during the time corresponding with basic rating life. In case of railway applications the bearings are often used in large groups and are preventively replaced after much shorter operating time as compared with their basic rating life. In the article there is a model which enables us to describe the bearings reliability in this specific case and to specify a number of failures which might be expected from a group of bearings during operating time, or to determine mean operating time between failures of bearings.

scholarly journals Determination of reliability of power supply of ship's responsible power receivers

2020 ◽  
pp. 22-26
Author(s):  
С.Е. Кузнецов ◽  
Н.А. Алексеев ◽  
А.А. Виноградов
Keyword(s):  
Power Systems ◽  
Power System ◽  
Power Supply ◽  
Electric Power System ◽  
Time To Failure ◽  
Parallel Operation ◽  
Diesel Generator ◽  
Operating Modes ◽  
Reliability Indicators ◽  
Supply Reliability

Изложена методика расчета показателей безотказности электроснабжения (вероятности безотказного электроснабжения и средней наработки до отказа) ответственных приемников морского судна, подключаемых к аварийному электрораспределительному щиту. Методика реализована применительно к судовой электроэнергетической системе с тремя источниками электроэнергии – двумя основными дизель-генераторными агрегатами, подключенными к главному электрораспределительному щиту, и одним аварийным дизель-генераторным агрегатом, подключенным к аварийному электрораспределительному щиту. Рассмотрены различные режимы работы судовой электроэнергетической системы: при работе до первого отказа одного основного дизель-генератора, при параллельной работе двух основных дизель-генераторов, при работе одного аварийного дизель-генератора; а также после обесточивания с учетом возможности последующего включения резервного или (и) аварийного дизель генератора. Методика, с соответствующими корректировками, может быть использована для расчета показателей безотказного электроснабжения в судовых электроэнергетических системах другой комплектации. Расчет показателей безотказности электроснабжения необходим при проектировании для обеспечения требуемого уровня надежности электроснабжения судовых приемников электроэнергии, а при эксплуатации – для предупреждения отказов и планирования технического обслуживания и ремонта элементов судовых электроэнергетических систем. The methodology for calculating the indicators of the reliability of power supply (the probability of failure-free power supply and the mean time to failure) of critical receivers of a sea vessel connected to the emergency electrical switchboard is presented. The technique is implemented in relation to a ship power system with three sources of electricity - two main diesel generator sets connected to the main electrical switchboard, and one emergency diesel generator set connected to an emergency electrical switchboard. Various operating modes of the ship's electric power system are considered: during operation until the first failure of one main diesel generator, during parallel operation of two main diesel generators, during operation of one emergency diesel generator; as well as after de-energizing, taking into account the possibility of subsequent switching on of the backup and / or emergency diesel generator. The technique, with appropriate adjustments, can be used to calculate indicators of reliable power supply in ship power systems of a different configuration. Calculation of power supply reliability indicators is necessary during design to ensure the required level of power supply reliability for ship power receivers, and during operation - to prevent failures and plan maintenance and repair of elements of ship power systems.

scholarly journals Wear Resistance and Titanium Adhesion of Cathodic Arc Deposited Multi-Component Coatings for Carbide End Mills at the Trochoidal Milling of Titanium Alloy

Technologies ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 38 ◽  
Author(s):  
Marina A. Volosova ◽  
Sergey V. Fyodorov ◽  
Stepan Opleshin ◽  
Mikhail Mosyanov
Keyword(s):  
Wear Resistance ◽  
Titanium Alloy ◽  
Operating Time ◽  
Maximum Effect ◽  
Time To Failure ◽  
Trochoidal Milling ◽  
Cathodic Arc Deposition ◽  
End Mills ◽  
Coated Carbide ◽  
Cathodic Arc

The work was devoted to the study of the effectiveness of the application of multi-component coatings, TiN–Al/TiN, TiN–AlTiN/SiN, and CrTiN–AlTiN–AlTiCrN/SiN, obtained by cathodic arc deposition to increase the wear resistance of 6WH10F carbide end mills in trochoidal milling of titanium alloy. The surface morphology of the tool with coatings was studied using scanning electron microscopy, and surface roughness texture was estimated. Microhardness and elastic modulus of the coated carbide tool surface layer were determined by nanoindentation. The process of sticking titanium to the working surface of the tool and quantitative evaluation of end mill wear with multi-component coatings at the trochoidal strategy of milling titanium alloy was studied. The CrTiN–AlTiN–AlTiCrN/SiN coating showed the maximum value of the plasticity index at the level of 0.12. The maximum effect of reducing the wear rate was achieved when using a tool with a CrTiN –AlTiN–AlTiCrN/SiN coating when the operating time to failure of end mills was increased by 4.6 times compared to samples without coating, by 1.4 times compared with TiN–Al/TiN coating and 1.15 times compared with TiN–AlTiN/SiN coating.

scholarly journals Diagnostics of supercapacitors

2018 ◽  
Vol 182 ◽  
pp. 01009 ◽  
Author(s):  
Valeriy Martynyuk ◽  
Oleksander Eromenko ◽  
Juliy Boiko ◽  
Tomasz Kałaczyński
Keyword(s):  
Mathematical Model ◽  
Mathematical Models ◽  
Methodological Approach ◽  
Frequency Dispersion ◽  
Technical Condition ◽  
Transient Processes ◽  
Nonlinear Frequency ◽  
Diagnostic Reliability ◽  
General Reliability ◽  
The Mathematical Model

The paper represents the mathematical model for diagnostics of supercapacitors. The research objectives are the problem of determining a supercapacitor technical condition during its operation. The general reliability of diagnostics is described as the methodological and instrumental reliabilities of diagnostics. The instrumental diagnostic reliability of supercapacitor includes the probabilities of errors of the first and second kind, α and β respectively. The methodological approach to increasing the reliability of supercapacitor diagnostic has been proposed, in terms of multi-parameter supercapacitor diagnostic by applying nonlinear, frequency dependent mathematical models of supercapacitors that take into account nonlinearity, frequency dispersion of parameters and the effect of transient processes in supercapacitors. The more frequencies, operating voltages and currents are applied in the supercapacitor diagnostics, the more methodological reliability of diagnostics will increase in relation to the methodological reliability of supercapacitor diagnostics when only one frequency, voltage and current are applied.

Development of Fault Diagnosis and Failure Prediction Techniques for Small Gas Turbine Engines

2001 ◽  
Author(s):  
Craig R. Davison ◽  
A. M. Birk
Keyword(s):  
Fault Diagnosis ◽  
Gas Turbine ◽  
Operating Time ◽  
Turbine Engines ◽  
Time To Failure ◽  
Gas Turbine Engines ◽  
Ambient Conditions ◽  
Engine Operation ◽  
Maintenance Cycle ◽  
Prediction Techniques

A computer model of a gas turbine auxiliary power unit was produced to develop techniques for fault diagnosis and prediction of remaining life in small gas turbine engines. Due to the relatively low capital cost of small engines it is important that the techniques have both low capital and operating costs. Failing engine components were identified with fault maps, and an algorithm was developed for predicting the time to failure, based on the engine’s past operation. Simulating daily engine operation over a maintenance cycle tested the techniques for identification and prediction. The simulation included daily variations in ambient conditions, operating time, load, engine speed and operating environment, to determine the amount of degradation per day. The algorithm successfully adapted to the daily changes and corrected the operating point back to standard conditions to predict the time to failure.

scholarly journals Stochastic models for ensuring parametric reliability of the construction machines

2021 ◽  
pp. 262-273
Author(s):  
Galyna Getun ◽  
Vitalii Les'ko ◽  
Iryna Bezklubenko ◽  
Olena Balina ◽  
Yurii Butsenko
Keyword(s):  
Methodological Approach ◽  
Hydraulic Drive ◽  
Hydraulic Cylinder ◽  
Technical Condition ◽  
Technical Problems ◽  
Reliability Models ◽  
Reliability Indicators ◽  
Hydraulic Machines ◽  
Parametric Reliability ◽  
Analysis Of Failures

The solution of technical problems to ensure the working capacity is largely determined by the effectiveness of theoretical and applied developments in an area of estimation and prediction of their reliability indicators. An effective approach to the analysis of failures and the development of operability and parametric reliability models provides an opportunity to obtain more adequate models of reliability of hydraulic drives of machines, as they more fully take into account the specifics of the structure and functioning of the hydro drive elements of construction machines, their relationships and features of the formation of parameters failures. And this will allow to get more real and accurate results of estimation of reliability indicators of hydraulic drives of both construction and other hydraulic machines. They do not exhaust all possible variants of models that can take place when analyzing the reliability of hydraulic drives of machines, but at the same time they to a certain extent extend and refine the set of known reliability models. Specific in terms of formation of parametrical failures are such consistently connected in terms of the layout of hydraulic elements, as working sections of hydraulic distributors and hydraulic cylinders, which are part of the subsystems of GPs and form the so-called functional areas (FA). Reaching the FA limit is a compatible result of the combined random process of evolution of the volumetric efficiency JCUA  these elements, and the technical condition of the FA is estimated to be generalized by the JCUA, which equals the product of the JCUA of consecutively connected elements: . In this case, the probability of maintaining the capacity of the FA will be: . The processing of diagnostic information and the study of the reliability of GPs in real conditions of their operation showed that the distribution of JCUD hydraulic elements with a sufficient degree of consistency can be described under several theoretical laws. It is considered when the JCUA sections of the hydraulic distributor and hydraulic cylinder are distributed by gamma distribution and exponential distribution. The use of the general methodological approach to the analysis of failures and the construction of models of operability and parametric reliability provides an opportunity to obtain more adequate models of reliability of hydraulic drives of machines, as they more fully take into account the specifics of the structure and functioning of the hydraulic drive elements, They don't exhaust all possible models that can take place when analyzing the reliability of hydraulic drives, but at the same time they are to some extent expanding and refining the range of already known models of reliability.

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