scholarly journals Aircraft maintenance system simulation mathematical model construction

2021 ◽  
Vol 24 (4) ◽  
pp. 38-49
Author(s):  
Yu. I. Samulenkov ◽  
Ya. A. Filatova ◽  
A. D. Gruzd
Keyword(s):  
Mathematical Model ◽  
Technical Condition ◽  
Spare Parts ◽  
Aircraft Maintenance ◽  
Time Duration ◽  
Functional Systems ◽  
Maintenance System ◽  
Study Results ◽  
Modeling Algorithm

The development of the aviation transport system is characterized by sophistication of interacting objects, the multi-criteria nature of the tasks to be solved and difficulties in making management decisions. For example, modern medium haul aircraft are fitted with up to 25,000 sensors to monitor the performance capabilities of functional systems components. Numerous ground-based instrumental methods and means of diagnosing the technical condition are used. This requires the development of methods and algorithms for determining and monitoring the criteria of limiting state of the monitored components and functional systems of aeronautical equipment. In this regard, analytical models of predictive estimate for the technical condition of aeronautical equipment, determination of aircraft maintenance modes and provision of spare parts and materials become essential. The paper proposes a scheme of the aircraft fleet maintenance system modeling algorithm and deducing the mathematical model of the optimal number of aircraft states in order to exclude secondary and subjective factors. The method of statistical modeling based on Markov processes with discrete states and continuous time is the basis of the proposed analytical model. The proposed method is reduced to the synthesis of some modeling algorithm of the investigated process that simulates the complex system components behavior and interaction as well as random perturbing factors. A distinctive feature of the presented algorithm is determination of the predominant estimated dependences of transition probabilities and intensities taking into account the requirements of the modern regulatory framework in terms of reliability of equipment and diagnosing the technical condition. The analysis of the predominant estimated dependencies study results in the conditions of operation of the aircraft maintenance system confirmed a high degree of correlation of the time duration effect on the particular states in order to diagnose the technical condition depending on the diagnostic concept. The proposed simulation model can be used for the aircraft technical condition predictive estimate, aircraft gas turbine engines and functional systems.

scholarly journals Determination of the type of repair work based on the results of survey and monitoring of the technical condition of buildings

2020 ◽  
Vol 157 ◽  
pp. 06023 ◽  
Author(s):  
Aleksandr Birjukov ◽  
Anatoly Lebedkin ◽  
Yurii Birjukov ◽  
Viktor Pchelkin
Keyword(s):  
Mathematical Model ◽  
Fuzzy Logic ◽  
Set Theory ◽  
Fuzzy Set Theory ◽  
Technical Condition ◽  
Capital Investments ◽  
Repair Work ◽  
Fuzzy Logic Method ◽  
Maintenance Work

This article is devoted to structural scrutiny of a building. The technical condition of buildings affects such characteristics of a building as safety, reliability, durability and maintainability. However, in the absence of reliable information on the technical condition of buildings, structural survey or monitoring of а building in order to determine the category of technical condition is necessary. The purpose of this work is to develop an economic and mathematical model for determining the type of maintenance work based on the results of structural scrutiny and monitoring of a building. The article is of importance because the final stage of the survey gives a qualified opinion on the level of structural scrutiny of a building, and on the basis of this opinion repair work eliminating physical and moral deterioration and providing in accordance with specifications renovation of the building are planned. The scientific novelty of the economic and mathematical model developed by the authors on the results of building structural scrutiny lies in the application of the fuzzy set theory and fuzzy logic method for determining of the level of physical and moral deterioration of a building consistent with a certain type of repair work and followed by the necessary capital investments.

scholarly journals Determination of the level of separate rail failure using the indicator of their reliability

2018 ◽  
Vol 230 ◽  
pp. 01016
Author(s):  
Anatolii Shtompel ◽  
Oleksii Skoryk ◽  
Vadym Novikov ◽  
Yuliia Kravchenko ◽  
Yevhen Korostelov
Keyword(s):  
Mathematical Model ◽  
Regression Analysis ◽  
Railway Track ◽  
Track Structure ◽  
Safety Level ◽  
Track Maintenance ◽  
Maintenance System ◽  
Operation Conditions ◽  
Reported Data

During the operation, the upper railway track structure constantly tends to age, which includes the increasing number of failures. This process is controlled by the track maintenance system, which provides for the current maintenance of the track in a certain railway section. As part of the current maintenance of the track, in particular, works are performed to eliminate defective elements of the upper railway track structure, which appeared during functioning of the track structure. The dependence of the operational cargo turnover on the amount of transported cargoes has been analyzed. It is directly related to the issues of organization of maintenance of the railway track structure taking into account the current track operation conditions. Regression analysis of the reported data allowed establishing a mathematical model of the dependence of the value of operational cargo turnover on the value of the transported cargo. The service life of rails (rail bars) in the track section has been established to be related to the indicator separate rail failure during the period of operation of the upper railway track structure by defects. The safety level of rails (rail bars) can be determined based on the value of this indicator.

scholarly journals A Reliability-Based Approach to Nonrepairable Spare Part Forecasting in Aircraft Maintenance System

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Nataša Z. Kontrec ◽  
Gradimir V. Milovanović ◽  
Stefan R. Panić ◽  
Hranislav Milošević
Keyword(s):  
Spare Part ◽  
Spare Parts ◽  
Inventory Systems ◽  
Decision Making Process ◽  
Aircraft Maintenance ◽  
Inventory Models ◽  
Stochastic Nature ◽  
Maintenance System ◽  
Reliability Characteristics ◽  
Maintenance Systems

In recent times, spare parts inventory systems have been extensively researched, but most inventory models were not fully adequate due to the stochastic nature of inventory environment. This paper proposes an approach that supports decision making process in planning and controlling of spare parts in aircraft maintenance systems. Reliability characteristics of aircraft consumable parts were analyzed in order to substantiate this approach. Moreover, the proposed reliability model was used to evaluate characteristics of subassemblies and/or assemblies these parts belong to. Finally, an innovative approach for determining the total amount of parts required in inventory and underage costs, based on observing the total unit time as a stochastic process, is presented herein.

scholarly journals METHODOLOGY FOR ENERGY-EFFICIENCY INVESTIGATION OF ELECTRICAL CONSUMERS

2016 ◽  
Vol 18 (4) ◽  
Author(s):  
ANDONOV KONDYU ◽  
DINOLOV OGNYAN ◽  
MIHAILOV LIUDMIL
Keyword(s):  
Mathematical Model ◽  
Energy Efficiency ◽  
Electrical Energy ◽  
Belt Conveyor ◽  
Thermo Electric ◽  
Conveyor System ◽  
Electric Drives ◽  
Study Results

<p>Uniform indications for electric consumers classifying are determined according to their technological signs and the physical forms of electrical energy conversion. Levels of consumption in electrical consumers are defined, on the basis of which 29 indexes for investigation, evaluation and comparison of the energy efficiency in electric drives are systematized. The indexes are distributed into 6 groups. Dependencies are defined and methods are developed for determination of the indexes system. An aggregate mathematical model for monitoring and evaluating the energy efficiency of grouped electric drives is synthesized. Case-study results for a typical belt-conveyor system in a thermo-electric power plant are obtained.</p>

scholarly journals MATHEMATICAL MODEL OF FORECASTING AND DEFINITION OF THE SIZE OF SPARE PARTS FOR AUTOMOTIVE SERVICE STATIONS WITH CONSIDERATION OF LOSS OF SALES

2020 ◽  
Vol 2 (47) ◽  
pp. 173-182
Author(s):  
Khavruk V ◽  
Keyword(s):  
Mathematical Model ◽  
Seasonal Variation ◽  
Inventory Management ◽  
Spare Part ◽  
Spare Parts ◽  
Multiplicative Model ◽  
Lost Sales ◽  
Seasonal Component ◽  
The Mathematical Model

The article deals with the order of formation of the mathematical model of forecasting and determination of the volume of spare parts, taking into account lost sales on the basis of actual expenses for repairs and sales through trade Object of research - system of inventory management of car maintenance stations Purpose of the study - to carry out research of mathematical model of forecasting and determination of spare parts volume taking into account lost sales and to find out the main components of it. Method of the study - the analysis and formalization: quantitative indicators of automobile parts reserves, methods of forming components and parameters of a mathematical model. It is established that the methodology of constructing a mathematical model involves the formalization of the main processes of the cost of automotive spare parts. The mathematical model includes the costs of spare parts: 1) for repairs of cars; 2) through the sale of a spare part in a shop operating at a service station. It was found out that in order to take into account the lost sales of spare parts, it is necessary to clearly register customer inquiries, indicating the factory catalogs of spare parts numbers, their number. In this case, in case of the need for a spare part and its presence in the warehouse of the enterprise, the client refuses to purchase, then such a requirement is not taken into account as dissatisfied. The construction of a mathematical multiplicative model of prediction and determination of the amount of spare parts based on lost sales in which the value of the seasonal component is not a constant, but represents a certain proportion of the trend value. The formulas for determining the need for spare parts in a multiplicative model based on parabolic, linear trends of demand and seasonal variation are considered and given. The importance of the seasonal component in the mathematical model of forecasting is substantiated; it is a factor of forecasting error, it allows to find out the causes of fluctuations and to calculate the insurance stock of parts. To calculate the seasonal component, a method of correction of the trend equation with an asymmetric seasonal wave is presented. The results of the article can be used to increase the efficiency of inventory management at both technical maintenance stations of cars and any subjects of entrepreneurial activity, in the case when there is a problem of dissatisfied consumer demand. Forecast assumptions about the object of study - the specification of the model for determining the volume of spare parts by studying the seasonal fluctuations in demand and studying the main trends in the development of car service services and the existing model range of cars, their age composition. KEYWORDS: DETAIL, SPARE PARTS, PROBABILITY, QUANTITY, MODEL, VOLUME, PERIOD, DEMAND, NEED, FORECAST, SALE, IMPLEMENTATION, EQUATION, SERIES, SEASONAL VARIATION, TREND.

DETERMINATION OF PERFORMANCE INDICATORS OF THE TRUCK KrAZ-6510TE

2020 ◽  
pp. 19-26
Author(s):  
Olexandr Pavlenko ◽  
Serhii Dun ◽  
Maksym Skliar
Keyword(s):  
Mathematical Model ◽  
Surface Friction ◽  
Building Structures ◽  
Maximum Torque ◽  
Military Equipment ◽  
Military Vehicles ◽  
Force Magnitude ◽  
Vehicle Mobility ◽  
The Mathematical Model

In any economy there is a need for the bulky goods transportation which cannot be divided into smaller parts. Such cargoes include building structures, elements of industrial equipment, tracked or wheeled construction and agricultural machinery, heavy armored military vehicles. In any case, tractor-semitrailer should provide fast delivery of goods with minimal fuel consumption. In order to guarantee the goods delivery, tractor-semitrailers must be able to overcome the existing roads broken grade and be capable to tow a semi-trailer in off-road conditions. These properties are especially important for military equipment transportation. The important factor that determines a tractor-semitrailer mobility is its gradeability. The purpose of this work is to improve a tractor-semitrailer mobility with tractor units manufactured at PJSC “AutoKrAZ” by increasing the tractor-semitrailer gradeability. The customer requirements for a new tractor are determined by the maximizing the grade to 18°. The analysis of the characteristics of modern tractor-semitrailers for heavy haulage has shown that the highest rate of this grade is 16.7°. The factors determining the limiting gradeability value were analyzed, based on the tractor-semitrailer with a KrAZ-6510TE tractor and a semi-trailer with a full weight of 80 t. It has been developed a mathematical model to investigate the tractor and semi-trailer axles vertical reactions distribution on the tractor-semitrailer friction performances. The mathematical model has allowed to calculate the gradeability value that the tractor-semitrailer can overcome in case of wheels and road surface friction value and the tractive force magnitude from the engine. The mathematical model adequacy was confirmed by comparing the calculations results with the data of factory tests. The analysis showed that on a dry road the KrAZ-6510TE tractor with a 80 t gross weight semitrailer is capable to climb a gradient of 14,35 ° with its coupling mass full use condition. The engine's maximum torque allows the tractor-semitrailer to overcome a gradient of 10.45° It has been determined the ways to improve the design of the KrAZ-6510TE tractor to increase its gradeability. Keywords: tractor, tractor-semitrailer vehicle mobility, tractor-semitrailer vehicle gradeability.

Validation of mathematical model of electrothermal calculation of DC catenary on the basis of scale model

2018 ◽  
Vol 77 (4) ◽  
pp. 222-229 ◽  
Author(s):  
A. V. Paranin ◽  
A. B. Batrashov
Keyword(s):  
Mathematical Model ◽  
Operating Conditions ◽  
Scale Model ◽  
Contact Network ◽  
Scaled Model ◽  
Cross Sectional ◽  
Current Collection ◽  
Topological Features ◽  
Study Results ◽  
Real Physical Process

The article compares the results of calculation of the finite element simulation of current and temperature distribution in the scale model of the DC catenary with the data of laboratory tests. Researches were carried on various versions of the structural design of catenary model, reflecting the topological features of the wire connection, characteristic of the DC contact network. The proportions of the cross-sectional area of the scaled model wires are comparable to each other with the corresponding values for real DC catenary. The article deals with the operating conditions of the catenary model in the modes of transit and current collection. When studying the operation of the scale catenary model in the transit mode, the effect of the structural elements on the current distribution and heating of the wires was obtained. Within the framework of the scale model, theoretical assumptions about the current overload of the supporting cable near the middle anchoring have been confirmed. In the current collection mode, the experimental dependences of the current in the transverse wires of the scale model are obtained from the coordinate of the current collection point. Using the model it was experimentally confirmed that in the section of the contact wire with local wear, not only the temperature rise occurs but also the current redistribution due to the smaller cross section. Thus, the current share in other longitudinal wires of the scale model increases and their temperature rises. Scale and mathematical models are constructed with allowance for laboratory clamps and supporting elements that participate in the removal of heat from the investigated wires. Obtained study results of the scale model allow to draw a conclusion about the adequacy of the mathematical model and its correspondence to the real physical process. These conclusions indicate the possibility of applying mathematical model for calculating real catenary, taking into account the uneven contact wear wire and the armature of the contact network.

Research on a Generating Method of Spiral Flutes of Hourglass Worm Gear Hob

2017 ◽  
Author(s):  
Yang Jie ◽  
Li Haitao ◽  
Rui Chengjie ◽  
Wei Wenjun ◽  
Dong Xuezhu
Keyword(s):  
Mathematical Model ◽  
Manufacturing System ◽  
Worm Gear ◽  
Virtual Manufacturing ◽  
Transmission Ratio ◽  
Method Of Determination ◽  
Generating Method ◽  
Multiple Threads ◽  
Different Shapes

All of the cutting edges on an hourglass worm gear hob have different shapes and spiral angles. If the spiral angles are small, straight flutes are usually adopted. But for the hob with multiple threads, the absolute values of the negative rake angles at one side of the cutting teeth will greatly affect the cutting performance of the hob if straight flutes are still used. Therefore, spiral flutes are usually adopted to solve the problem. However, no method of determination of the spiral flute of the hourglass worm gear hob has been put forward till now. Based on the curved surface generating theory and the hourglass worm forming principle, a generating method for the spiral flute of the planar double enveloping worm gear hob is put forward in this paper. A mathematical model is built to generate the spiral flute. The rake angles of all cutting teeth of the hob are calculated. The laws of the rake angles of the cutting teeth of four hobs with different threads from one to four threads are analyzed when straight flutes and spiral flutes are adopted respectively. The laws between the value of the negative rake angles of the hob with four threads and the milling transmission ratio are studied. The most appropriate milling transmission ratio for generating the spiral flute is obtained. The machining of the spiral flutes is simulated by a virtual manufacturing system and the results verify the correctness of the method.

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