scholarly journals Mathematical models and methods of prolongation of operating lifetimes for expensive objects

2019 ◽  
Vol 298 ◽  
pp. 00078
Author(s):  
Vladimir Trukhanov ◽  
Mikhail Kukhtik ◽  
Natal’ya Fyodorova
Keyword(s):  
Probabilistic Method ◽  
Reliability Function ◽  
Technical State ◽  
Distribution Law ◽  
Method Of Calculation ◽  
Actual Load ◽  
Operating Lifetime ◽  
Complex Technical Systems ◽  
The Mathematical Model ◽  
Element Base

The article is devoted to the relevant issue of prolongation of operating lifetimes for expensive objects. The methods of prolongation of operating lifetimes for complex technical systems have been described. In particular, the mathematical model of prolongation of operating lifetimes by the calculation and analytical method, which is based on normal distribution law of actual load and durability, has been represented. The experimental method, which is based on analysis of actual technical state of element base and material, has been described. The probabilistic method of calculation of reliability function during prolonged operating lifetime taking into account actual technical state of element base has been represented.

METHODS OF PROLONGATION OF OPERATING LIFETIMES FOR COMPLEX TECHNICAL SYSTEMS LIKE MOVABLE MOUNTINGS OF SPECIAL PURPOSE

2019 ◽  
pp. 46-51
Author(s):  
V. M. Trukhanov ◽  
M. P. Kukhtik
Keyword(s):  
Probabilistic Method ◽  
Reliability Function ◽  
Technical State ◽  
Distribution Law ◽  
Method Of Calculation ◽  
Actual Load ◽  
Operating Lifetime ◽  
Complex Technical Systems ◽  
Technical Systems ◽  
Element Base

The article is devoted to the relevant issue of prolongation of operating lifetimes for complex technical systems like movable mountings of special purpose. The issues of mean and residual lives have been considered, mathematical models of mean and residual lives have been represented. Methods of prolongation of operating lifetimes for expensive objects of special purpose like movable mountings have been described. In particular, mathematical model of prolongation of operating lifetimes by the calculation and analytical method, which is based on of normal distribution law of actual load and durability, has been represented. The experimental method, which is based on analysis of actual technical state of element base and material, has been described. The probabilistic method of calculation of reliability function during prolonged operating lifetime taking into account actual technical state of element base has been represented.

ASSESSMENT AND FORECASTING OF FREIGHT CAR TECHNICAL STATE

2021 ◽  
Vol 2021 (5) ◽  
pp. 40-47
Author(s):  
Elena Rozhkova
Keyword(s):  
Graphical Model ◽  
Technical State ◽  
Distribution Law ◽  
Repair Service ◽  
Statistic Modeling ◽  
Average Operating ◽  
Freight Car ◽  
Run Up ◽  
Definition Of ◽  
The Given

The purpose of this work is the assessment and forecasting of freight car technical state at life stages. The scientific novelty consists in the definition of car operating run-up to the first failure and between failures, and also in the definition of car life to considerable repair fulfillment from the operating run between failures and development of a graphical model of freight car reliability. As a result of the statistic modeling of gondola car operating runs up to the first failure it is defined that the given random value conforms to a normal distribution law, the first car setoff in TOR due to wear failure takes place at the operating run of 85,000 km. Besides the operating run-up to the first failure there was defined an operating run-up between failures. It is proved that the operating run-up between failures conforms to the exponential law of distribution, the mathematical expectation of which is 13,000 km. The results of investigations mentioned above formed the basis of the graphical model of car reliability. An inter-repair service life of a car can be represented as a sum of the following operating run-ups: operating run-ups to the first failure, the product of operating run-ups between failures and the number of failures and a residual operating run-up (from the utmost current repair to the nearest scheduled repair). On the basis of the mentioned it is expedient to consider a technology for the realization of an enlarged repair with the purpose of the repetition exclusion in car setoffs during the inter-repair term. On the basis of the simulator there is obtained the dependence of the frequency of car enlarged current repair fulfillment depending on average operating run-up between failures. At present an enlarged current repair must be carried out only for gondola cars in the planned order after having reached 80,000 km. The repair mentioned can be carried out both under depot conditions, and under conditions of repair workshops. The advantage of such a system of repair consists in the increase car work reliability during the inter-repair term.

The Study on Residual Stress Testing of Humidity Effect and Distribution Law for PMMA

2013 ◽  
Vol 631-632 ◽  
pp. 358-361
Author(s):  
Shang Wei ◽  
Yang Xiao Jing ◽  
Mao Cui ◽  
Guo Long
Keyword(s):  
Mechanical Properties ◽  
Mathematical Model ◽  
Residual Stress ◽  
Stress Testing ◽  
Phase Shifting ◽  
Distribution Law ◽  
Humidity Effect ◽  
Boundary Stress ◽  
The Mathematical Model ◽  
Humidity Environment

Polymethyl methacrylate (PMMA) has shown some excellent performances. However the humidity environment affects mechanical properties of PMMA seriously. In this work, the digital phase-shifting photoelasticity is used to test the humidity stress of the boundary according to which we concluded that the boundary stress decreases gradually from the boundary to the inner. The mathematical model of the boundary stress distribution is established based on the distribution law of the boundary stress. This mathematical model can be used to predict the effect of the humidity environment to the boundary stress, and guide PMMA to use safely.

scholarly journals Analysis of Mathematical Model for Migration Law of Radon in Underground Multilayer Strata

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Wei Zhang ◽  
Dongsheng Zhang ◽  
Xufeng Wang ◽  
Mengtang Xu ◽  
Hongzhi Wang
Keyword(s):  
Mathematical Model ◽  
Radon Concentration ◽  
Chemical Properties ◽  
Separation Process ◽  
Distribution Law ◽  
Geological Conditions ◽  
Different Depths ◽  
The Mathematical Model ◽  
Migration Law

This paper summarized the separation process of radon based on its geophysical-chemical properties. Taking into account the geological conditions of mining, the mathematical model of radon migration in underground multilayer strata (UMS) was established to investigate the distribution law of radon concentration in UMS. It was found that the distribution of radon concentration in UMS is affected by both the properties of the strata and the depth of cover and the radon concentration law varies at different depths even in the same layer stratum. At last, in order to validate the derivation result of the mathematical model of radon migration in UMS, the actual measured values (AMV) and the calculated values (CV) were compared further. As a result, the CV was found to be approximately equal to the AMV with deviation values (DV) less than 5%, which indicates that the derivation result of the mathematical model of radon migration in UMS is correct.

scholarly journals ANGULAR MOVEMENT PROGRAM CALCULATION PROCEDURE SPACECRAFT WHEN TAKING THE SURFACE OF THE EARTH IN AREA MODE

2019 ◽  
Vol 27 (4) ◽  
pp. 86-100
Author(s):  
Oleg Viktorovich Lutz ◽  
Galina Alexandrovna Borshchova ◽  
Evgeny Dmitrievich Yarmolchuk ◽  
Alexander Alekseevich Manoilenko
Keyword(s):  
Mathematical Model ◽  
Angular Motion ◽  
Field Of View ◽  
Method Of Calculation ◽  
Angular Movement ◽  
The Earth ◽  
Program Calculation ◽  
Large Width ◽  
Definition Of ◽  
The Mathematical Model

Currently increased interest in satellite images of the Earth's surface with high resolution terrain  (1 to 10 m). To obtain such images, you must use a long focus optical system (OS) having a limited field of view that does not allow the images of the large width. To increase the effectiveness of shooting in modern space systems (SS) Earth observation provides the opportunity after shooting a segment of the Earth's surface to redirect the OS to another area and spend it shooting. With sufficient speed shift OS it is possible to survey two or more adjacent parcels, which is almost equivalent to the corresponding increase in the width of the field of view of the removing apparatus. In this connection there is the task of restoring the OS, which is solved by the use of appropriate hardware and software control the angular movement of the removing apparatus. When creating the SS there is also the need to solve the following tasks: calculation of the program angular motion in a given length of the removable sections and a predetermined number of adjacent strips to be shot, with the purpose of definition of system requirements, spacecraft (SC) control and calculation under given characteristics of the system orientation of the SC possible number of the maximum length and remove adjacent portions of the surface of the Earth. To solve these tasks the mathematical model software of angular motion of the SC. Given the necessary initial data, mathematical model and method of calculation of kinematic parameters of a software angular motion of a SC in the mode of area highway shooting adjacent sections of the Earth's surface located at a predetermined distance from a trace route SC; examples and results of numerical calculations of the programmes angular motion by moving the instrument in remote sensing.

scholarly journals EVALUATION OF THE RELIABILITY TEST RESULTS OF A ROCKET ENGINE BASED ON A LOGICAL-PROBABILISTIC METHOD

2019 ◽  
Vol 27 (4) ◽  
pp. 21-24
Author(s):  
Sergey Mikhailovich Podolchak
Keyword(s):  
Rocket Engine ◽  
Probabilistic Method ◽  
A Priori ◽  
Rocket Engines ◽  
Test Results ◽  
Reliability Models ◽  
Complex Technical Systems ◽  
Priori Information ◽  
Theory Of Evidence ◽  
The Cost

A logical-probabilistic method for evaluating the test result is proposed, which is based on the theory of evidence of Dempster-Schafer with some assumptions that do not affect the final result. Currently, there is an acute question of creating new types of rocket technology in connection with a change in the situation on the international and domestic market. When creating new samples, it is necessary to pay special attention to the level of their reliability, but also remember to take into account the financial component of projects for the development and manufacture of products. In this regard, research is currently being conducted not only in the direction of increasing the reliability of complex technical systems, which include rocket engines, but also in reducing the cost of their refinement. One of the research options in this direction was proposed by the author in this work. The aim of the work and research as a whole was to demonstrate the capabilities of the chosen method for evaluating the test results, according to which it would be possible to draw conclusions about the success of the tests themselves. As studies have shown, the logical-probabilistic method for evaluating test results based on the Dempster-Schafer theory of evidence, due to the lack of a priori information, can be used in the development of new rocket engine models, but only in a narrow direction. More widely, this method can be used in the design of products based on accumulated experience (amount of information) on existing analogues. Dempster-Schafer proof theory can be applied at earlier design stages, but only in combination with other reliability models.

Measurement and Calculation of Heat Exchanger Performance Using Film Method

Volume 3 ◽  
2004 ◽  
Author(s):  
Che´rif Bougriou ◽  
Rachid Bessai¨h ◽  
Kerstin Eckert ◽  
Mahfoud Kadja
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Computer Code ◽  
Method Of Calculation ◽  
Finned Tubes ◽  
The Mathematical Model ◽  
The Heat Transfer Coefficient ◽  
Film Method

In this paper, we present a method of calculation by partial or total condensation of the water vapor contained in the humid air, over the smooth or finned tubes-heat recupurators. This study presents an implantation of the film method in a computer code developed here. The mathematical model used is validated by our experimental approach, using tubes bundles in staggered and aligned arrangements. The heat transfer coefficient by convection around the fin is supposed too be constant. The computer code predicts the heat flux exchanged in a range of 20% and 5%, in wet and dry regime, respectively. The apparent heat transfer coefficient by condensation can exceed 10 times the value of the heat transfer coefficient. The mathematical model used is validated with the experimental data obtained in this study.

scholarly journals Criteria Justification for Assessing the Technical Condition of Gearboxes of Mining Machines Based on Infrared Thermography

2020 ◽  
Vol 174 ◽  
pp. 03003 ◽  
Author(s):  
Evgeniy Kuzin ◽  
Boris Gerike ◽  
Vitaliy Shachmanov
Keyword(s):  
Heat Release ◽  
Theoretical Basis ◽  
Technical Condition ◽  
Operating Conditions ◽  
The Body ◽  
Mining Machine ◽  
Belt Conveyor ◽  
Actual Load ◽  
Early Failures ◽  
Complex Technical Systems

The paper presents the relevance of advanced assessment of the technical condition of complex technical systems. One of which is the gearbox of a mining machine. The main reasons for early failures of bearings are shown. The main share is occupied by problems of lubrication, incorrect installation and maintenance. The analysis of types of destruction of gears of mining machines is presented. The main share is occupied by the surface coloring of the teeth and sudden fracture of the tooth as a result of dynamic load. The theoretical basis for determining the heat release of bearings is given. The calculation of heat release is given of a shaft belt conveyor gearbox as an example, which is confirmed by thermographic studies under operating conditions. Justification of criteria for evaluating the technical condition of gearboxes of mining machines in the form of temperature anomalies recorded on the surface of the body, The actual load on the output shaft is taken into account.

scholarly journals METHOD OF STEPWISE SMOOTHING EXPERIMENTAL DEPENDENCES FOR PROBLEMS OF SHORT-TERM FORECASTING

2021 ◽  
Vol 2021 (3) ◽  
pp. 126-133
Author(s):  
Anatoly Anatolevich Ermakov ◽  
Tatyana Klimentyevna Kirillova
Keyword(s):  
Monotone Function ◽  
Operating Time ◽  
Smoothing Method ◽  
Monotone Functions ◽  
Short Term ◽  
Distribution Law ◽  
True Value ◽  
Complex Technical Systems ◽  
Short Term Forecasting ◽  
True Values

The article considers the correspondence of the step-by-step smoothing method as one of the possible algorithms for short-term forecasting of statistics of equal-current measurements of monotone functions, which represent the values of the determining parameters that evaluate the dynamics of the states of complex technical systems based on the operating time. The true value of the monitored parameter is considered unknown, and the processed measurement values are distributed normally. The measurements are processed by step-by-step smoothing. As a result of processing, a new statistic is formed, which is a forecast statistic, each value of which is a half-sum of the measurement itself and the so-called private forecast. First, the forecasts obtained in this way prove to have the same distribution law as the distribution law of a sample of equally accurate measurements. Second, the forecast trend should be the same as the measurement trend and correspond to the theoretical trend, that is, the true values of the monotone function. Third, the variance of the obtained statistics should not exceed the variance of the original sample. It is inferred that the method of step-by-step smoothing method can be proposed for short-term forecasting

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