scholarly journals Investigation of vibroisolating device reliability in grinding machine

2016 ◽  
Vol 1 (9) ◽  
pp. 10-15 ◽  
Author(s):  
С. Братан ◽  
S. Bratan ◽  
Екатерина Владецкая ◽  
Ekaterina Vladetskaya
Keyword(s):  
Failure Probability ◽  
Reliability Estimation ◽  
Parametric Synthesis ◽  
Rational Engineering ◽  
Machine Experiment ◽  
Mass Service ◽  
Device Reliability ◽  
Grinding Machine ◽  
Service Theory ◽  
Parametrical Optimization

For the search of rational engineering solutions on the design of vibroisolating devices of a machine functioning under conditions of a floating shop there is used a method of a morphological analysis. The undertakings carried out allowed solving a problem at the level of a structural arrangement optimization and parametric synthesis and creating new designs of a vibroisolating support and a vibroisolating device. On the basis of the regulations of a mass service theory there is offered a method for the operation reliability estimation of a machine vibroisolating device with the use of a graduated graph of states taking into account failure and restoration flows. The state of the system is determined by a set of equations of final likelihoods. A machine experiment has shown maintainability high enough of a vibroisolating device (more than 96 % of its life the device is in its operational status, and about 4% - in the repair (restoration) state of its subsystems). To the least reliable subsystem it should be related a drive (failure probability – 2.11%), further – vibro-isolator (failure probability – 1%), then – a body – (0.52%) and a fastening device (0.26%). The method allows defining device maintainability with the aid of a machine experiment and revealing least reliable subsystems and elements and also an expediency of their parametrical optimization.

Reliability of Buried Pipeline Using a Theory of Probability of Failure

2006 ◽  
Vol 110 ◽  
pp. 221-230 ◽  
Author(s):  
Ouk Sub Lee ◽  
Dong Hyeok Kim ◽  
Seon Soon Choi
Keyword(s):  
Failure Probability ◽  
Probability Of Failure ◽  
Operating Conditions ◽  
Reliability Estimation ◽  
Design Parameters ◽  
Buried Pipeline ◽  
Safety Level ◽  
First Order ◽  
Reliability Method ◽  
Corrosion Defects

The reliability estimation of buried pipeline with corrosion defects is presented. The reliability of corroded pipeline has been estimated by using a theory of probability of failure. And the reliability has been analyzed in accordance with a target safety level. The probability of failure is calculated using the FORM (first order reliability method). The changes in probability of failure corresponding to three corrosion models and eight failure pressure models are systematically investigated in detail. It is highly suggested that the plant designer should select appropriate operating conditions and design parameters and analyze the reliability of buried pipeline with corrosion defects according to the probability of failure and a required target safety level. The normalized margin is defined and estimated accordingly. Furthermore, the normalized margin is used to predict the failure probability using the fitting lines between failure probability and normalized margin.

scholarly journals Mathematical model of environmental waters purification

2019 ◽  
Vol 135 ◽  
pp. 01056
Author(s):  
Yuri Skolubovich ◽  
Alexey Skolubovich ◽  
Dmitry Volkov ◽  
Tamara Krasnova ◽  
Elena Gogina
Keyword(s):  
Mathematical Model ◽  
Mathematical Analysis ◽  
Stochastic Approach ◽  
Mathematical Tool ◽  
Environmental Waters ◽  
Mass Service ◽  
Coagulation Process ◽  
Service Theory

This article describes the use of the stochastic approach, in particular, mass service theory and the development of its methods, adapted directly to the coagulation process as a mathematical tool. The coagulation process will be concerned as a) supplying water to the mixer, b) processing it with reagents (coagulants), c) settling for the mathematical analysis of water clarification effectiveness.

Reliability Estimation for PVC Pipe Using Probability Theory and Stress Intensity Factor

2008 ◽  
Author(s):  
O. S. Lee ◽  
D. H. Kim ◽  
H. M. Kim ◽  
H. B. Choi
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Wall Thickness ◽  
Failure Probability ◽  
Probabilistic Method ◽  
Reliability Estimation ◽  
State Function ◽  
Operating Pressure ◽  
Reliability Method

In this paper, the reliability estimation of Polyvinyl chloride (PVC) pipelines is performed by utilizing the probabilistic method, which accounts for the uncertainties in the load and resistance parameters in the limit state function (LSF). The LSF is formulated with the help of fracture control concept including the stress intensity factor (SIF) for the pipeline having crack or crack like defects. The common cracks found at pipeline can be assumed as semi-elliptical shape and the main load is hoop stress due to the internal pressure. The FORM (first order reliability method) and the SORM (second order reliability method) are carried out to estimate the failure probability of pipeline utilizing the SIF for semi-elliptical crack. The reliability is assessed using this failure probability. It is found that the failure probability increases with the operating pressure, and the decrease of the pipeline wall thickness, and the increase of the crack depth, the crack length, the outside diameter of pipeline. The failure probability increases when the initial crack approaches to a semi-circle shape of crack and the failure probability steeply increases at the ratios of larger than 0.5 of a/t and larger than 30 of D/t. Moreover, it is recognized that the effects of the fracture toughness and the pipe wall thickness on the failure probability are the significant one.

Reliability Estimation of Solder Joint by Using the Failure Probability Models

2006 ◽  
Vol 326-328 ◽  
pp. 621-624 ◽  
Author(s):  
Ouk Sub Lee ◽  
Man Jae Hur ◽  
Jai Sug Hawong ◽  
No Hoon Myoung ◽  
Dong Hyeok Kim
Keyword(s):  
Solder Joint ◽  
Boundary Conditions ◽  
Failure Probability ◽  
Coefficient Of Thermal Expansion ◽  
Bending Moment ◽  
Fatigue Loading ◽  
Reliability Estimation ◽  
Probability Models ◽  
Reliability Method ◽  
The Difference

The differences in the coefficient of thermal expansion (CTE) between the chip and the FR-4 board generate the shear strains and the bending moment in the solder joint. It seems to be a main cause of failure in the solder joint when the chip and the FR-4 board are heated repeatedly. Thus, the fatigue loading induced by thermal cycling is a major concern in the reliability of the solder joint. The magnitude of shear strain and the final failure are known to be influenced by varying boundary conditions such as the difference of CTE, the height of solder, the distance of the solder joint from the neutral point (DNP) and the temperature variation. In this paper, the effects of boundary conditions on the failure probability of the solder joint are studied by using the failure probability models such as the First Order Reliability Method (FORM) and the Monte Carlo Simulation (MCS). Furthermore, the stiffness of the solder joint is considered to investigate the influence at the failure probability.

Reliability Estimation of Buried Pipeline Using FORM, SORM and Monte Carlo Simulation

2006 ◽  
Vol 326-328 ◽  
pp. 597-600 ◽  
Author(s):  
Ouk Sub Lee ◽  
Dong Hyeok Kim
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Exposure Time ◽  
Failure Probability ◽  
Reliability Estimation ◽  
Buried Pipeline ◽  
First Order Reliability Method ◽  
First Order ◽  
Reliability Method ◽  
The Difference

In this paper, the failure probability is estimated by using the FORM (first order reliability method), the SORM (second order reliability method) and the Monte Carlo simulation to evaluate the reliability of the corroded pipeline. It is found that the FORM technique is more effective in estimating the failure probability than the SORM technique for B31G and MB31G models with three different corrosion models. Furthermore, it is noted that the difference between the results of the FORM, the SORM and the Monte Carlo simulation decreases with the increase of the exposure time.

scholarly journals Multichannel System State Graph of Combine Harvesters Branded Technical Service in Uzbekistan

2020 ◽  
Vol 14 (1) ◽  
pp. 46-49
Author(s):  
M. T. Toshboltaev ◽  
Z. A. Seytimbetova
Keyword(s):  
Service System ◽  
State Graph ◽  
Technical Service ◽  
System State ◽  
Multichannel System ◽  
Channel System ◽  
Average Value ◽  
Mass Service ◽  
Combine Harvesters ◽  
Service Theory

The authors showed that the multichannel system state graph of modern tractors, combines and agricultural machinery in Uzbekistan, by the nature of its functioning, was a kind of mass service system. They confirmed that this circumstance was not taken into account when studying the existing system of corporate technical service. They pointed out the relevance of determining the influence of the branded technical service system parameters on its condition using the methods of the mass service theory. (Research purpose) To evaluate the state parameters of a proprietary technical service multichannel system according to the results of the timing of combine harvesters maintenance. (Materials and methods) The authors studied the multi-channel system state graph of a proprietary technical service without a queue. The system included 109 Case-2166 combine harvesters and 7 car-mobile workshops. They used the methods of mass service theory. (Results and discussion) The authors established a linear relationship between the number of occupied car-mobile workshops and the average value of the service time at a constant intensity of requirements. It was revealed that it took 3.33 hours to fix one malfunction of one combine, that is, one workshop would be occupied. If 3.24 demands were received in the service center in one hour, then all 7 auto-moving workshops would be occupied. (Conclusions) The authors revealed that for a single-channel proprietary technical service system the average value of the time for eliminating one malfunction of one combine should not exceed 3.33 hours. They calculated the parameters at which all channels (7 workshops) will be occupied in the 7-channel system of corporate technical service: 3.24 requirements arose in one hour, on average, each workshop took 2.16 hours to fix one malfunction.

OPTIMIZE THE ORGANIZATION OF THE ACCOUNTING SERVICE AND OTHER SERVICE FUNCTIONS USING THE THEORY OF MANAGEMENT OF MASS SERVICE SYSTEMS

2020 ◽  
Vol 1 (12) ◽  
pp. 19-24
Author(s):  
I. A. SLOBODNYAK ◽  
◽  
P. V. ANTIPINA ◽  
Keyword(s):  
Service System ◽  
Point Of View ◽  
Service Systems ◽  
Mathematical Methods ◽  
Economic Point ◽  
Mass Service ◽  
Basic Performance ◽  
Service Theory

The article is devoted to considering the use of modern mathematical methods for the purpose of analyzing the effectiveness of organizing of various services of the organization. With the example of the accounting service it is shown how the basic performance of the service can be defined using the position of mass service theory. Proposes an interpretation of all the major variables in the model from an economic point of view. The model is universal and can be used to assess the operation of any service that meets the parameters of the mass service system.

scholarly journals System Reliability Design Analysis of Propulsion Structures

1993 ◽  
Author(s):  
S. Mahadevan ◽  
S. Mehta ◽  
R. G. Tryon ◽  
T. A. Cruse
Keyword(s):  
Failure Probability ◽  
Rational Design ◽  
Failure Modes ◽  
Quantitative Information ◽  
Reliability Estimation ◽  
Computational Method ◽  
System Failure ◽  
Turbine Engine ◽  
Reliability Design ◽  
The Individual

The reliability of a gas turbine engine structure is affected by the uncertainties in the operating environment (speed, temperature etc.) as well as in the structural properties (material properties, geometries, boundary conditions etc.). A computational method for accurate reliability estimation under such uncertainties is described in this paper. Reliability computation for individual failure modes (burst, LCF etc.) as well as overall system failure is addressed. System failure probability is computed through the union of individual mode failures. The method also provides precise sensitivity information about the effect of each uncertain parameter on the individual failure probabilities as well as on the system failure probability. Such quantitative information helps rational design decisions as well as risk assessment and certification.

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