Fuzzy Reliability Research Articles

Fuzzy Reliability Calculation of Rolling Bearing’s Life

According to the traditional method of rolling bearing’s life calculation, the paper analyses the existing problems and calculative inaccuracy of it, puts forward the method of calculating the rolling bearing’s life by using basic Fuzzy reliability theory and establishes the model of calculating rolling bearing’s fuzzy reliability Life. Calculating the rolling bearing’s life by using Fuzzy Mathematics overcomes the shortcoming of traditional calculation. It is closer to objective reality.

Call for papers for a special section on fuzzy reliability

Call for papers for a special section on fuzzy reliability

Spare Parts Production Planning Model Based on Fuzzy Programming

In the field of civil aviation, MRO market has a strong seasonal characteristic. Combined with research on continuous airworthiness of the aircraft, the spare parts order procedure and flight planning process, and analysis on fuzzy demand and fuzzy production capacity, the model of spare parts order with fuzzy reliability constraints is established. Under the background of actual civil aviation enterprises, spare parts quantitative order model and algorithm in spare parts planning decision system in non-deterministic environment are put forward. It applies the theories and methods of fuzzy mathematics and probability and statistics, building the target programming model for reconfigurable spare parts, to formulate optimal reconfigurable spare parts production plan. Overall steps to solve the model are proposed, which make decision process in fuzzy environment more flexible, and reduce the number of emergency orders.

Fuzzy Reliability Analysis on the Kinematic Precision of Mechanism

Introduced the conventional failure criterion of the precision of motion of mechanism and the analytical methods of reliability, and then focused on fuzzy failure criterion of precision, advanced mechanism fuzzy reliability formulas, and illuminated the application of this method.

Design and research of a novel type of mechanical presses driven by three servo motors in parallel

A novel type of mechanical presses design driven by three servo motors in parallel is proposed to develop high stamping capacity based on the theory of generalized function sets, and then is improved to enhance its practicability in engineering practice. The inverse and forward kinematics analyses are conducted later. Based on the fuzzy probability theory, the computing method of fuzzy reliability of kinematic accuracy of slider is then obtained. Finally, with a set of optimized length parameters of the presses given, the fuzzy reliability is calculated, on the basis of which a typical deep-drawing process is simulated.

Reliability Evaluation of Complex System with Fuzzy Reliability of Components using Interval Nonlinear Programming

We have considered reliability of components of complex system is fuzzy in nature. Since reliability components are taken fuzzy in nature, so system reliability is also in fuzzy nature. We apply Zadeh’s extension principal and interval arithmetic operation to evaluate reliability of the system assembled with fuzzy reliability of components. We approximate the system reliability to a fuzzy number and evaluate the corresponding maximum divergence. Here, we demonstrate a bridge network whose components reliability are taken as triangular fuzzy number. Evaluating reliability of the system belongs to an interval. We have considered cost constrained goal as an interval number, interval nonlinear programming is used to find out the system reliability. Numerical examples are given to illustrate the approach to evaluate the system reliability.

Fuzzy Reliability Evaluation of RC Rigid-Frame Arch Bridge in Service

According to the basic principles and methods of the fuzzy reliability assessment to the existing bridge, RC rigid-frame arch bridge with Fuzzy reliability evaluation of a judgment factor sets of class I and class Ⅱare identified in this paper, aiming at the existing disease in this kind of bridge. Then, the fuzzy reliability comprehensive evaluation model of RC rigid-frame arch bridge is established. Meantime, the paper raises the membership function of each evaluation index; uses Analytic hierarchy process (AHP) to determine the weight vector of each factor. At last, a reliable practical analytical method for the evaluation of the existing RC rigid-frame arch bridge’s bearing capacity is obtained.

Call for papers for a special section on fuzzy reliability

Call for papers for a special section on fuzzy reliability

Fuzzy Reliability Evaluation of a Repairable System with Imperfect Coverage, Reboot and Common-cause Shock Failure

In the present investigation, we deal with the reliability characteristics of a repairable system consisting of two independent operating units, by incorporating the coverage factor. The probability of the successful detection, location and recovery from a failure is known as the coverage probability. The reboot delay and common cause shock failure are also considered. The times to failure of the components, time to failure due to common cause, time to repair and time to reboot are assumed to follow exponential distributions. The Markov model of the system is developed and the system state transition probabilities are determined which are further used to evaluate some reliability indices such as availability and mean time to failure. We use fuzzy logic approach for analyzing the system performance by assuming the trapezoidal membership functions of the system descriptors viz. failure rates and repair rates. The fuzzy mean time to failure and fuzzy availability have been established. A numerical experiment has been performed to validate the analytical results.

A new method to solve time-dependent intuitionistic fuzzy differential equations and its application to analyze the intuitionistic fuzzy reliability of industrial systems

To the best of our knowledge, there is no method in the literature for solving such differential equations in which all the parameters except independent variables are represented by intuitionistic fuzzy numbers. In this article, a new method is proposed for solving such nth-order time-dependent intuitionistic fuzzy linear differential equations. To show the application of the proposed method in real-life problems, the time-dependent intuitionistic fuzzy Kolmogorov’s differential equations, obtained by Markov model of condensate system, are solved by the proposed method, and the obtained solution is used to analyze the intuitionistic fuzzy reliability of condensate system.

Reliability Estimation Under The Fuzzy Environments

This paper proposes new methods for fuzzy reliability estimation where lifetime random variables have a distribution function with fuzzy parameter. First, a fuzzy estimation is constructed for the parameter. Then, using such a fuzzy estimation, a fuzzy reliability estimation is constructed. In first method, we used Buckley method with precise observation. In secound one we uesd fuzzy point estimation with fuzzy observation. In third method, using a fuzzy estimation of mean time to failure (MTTF), we constructed a fuzzy confidence bound and a fuzzy confidence band for reliability function for a given \(t_0\) and for a given \(\alpha_0\) respectively. This method has been used in lifetime distributions as fuzzy normal distribution, fuzzy exponential distribution and fuzzy Weibull distribution.

A new approach for analysis the fuzzy reliability using LR type interval valued flat vague set

This paper describes a vague sets-based fault tree technique to evaluate the reliability indices for power plant systems. Due to uncertainty in the collected data, all failure probabilities of the components of the system are represented by LR type interval valued flat vague sets. For preserving the shape of the LR type interval valued flat vague sets T ω -based arithmetic operations are used. An example of gas power plant is given to demonstrate the method described in this paper. By using this approach, the fuzzy system reliability can be analyzed in a more flexible and intelligent manner.

Fuzzy Reliability Analysis of Geocell Protective Slope Stability

In order to analyze the uncertainty existing in the stability of slope with geocell, the fuzziness of soil property parameters should be considered. In this paper, probability density function of structural performance function and membership function of the stability of slope with geocell was determined. The fuzzy reliability model of the stability of slope with geocell was established. The fuzzy reliability and fuzzy failure probability of slope with geocell instability were calculated, and the practicability of the calculated model was verified.

Study on Fuzzy Reliability of the Gravity Retaining and Protecting Structure for Foundation Pit

The major instable modes of the gravity retaining and protecting structure for foundation pit are overturning and slipping. Because of the stability of these geotechnical problems is affected by many uncertain factors, the stability analysis of them should be involved in the scope of the fuzzy and random event. Therefore, based on the theory of probability and fuzzy mathematics, the random and fuzzy characteristics were took into account, the calculating model of the fuzzy reliability of the gravity retaining and protecting structure for foundation pit was established. Through an engineering example’s calculating analysis of its overturning and slipping instable modes, the fuzzy instable probability and reliable index are calculated, some relevant conclusions are acquired via comparing with the traditional safety-coefficient method, and the feasibility of the fuzzy reliability method is testified.

Rock Slope Fuzzy Stochastic Damage Study

Fuzzy sub-space, with analysis on generalized uncertainty of damage, is setup in this paper when topological consistency of damage fuzzy and randomness on [0,1] scale being demonstrated deeply. Furthermore, deduced under fuzzy characteristics translation are three fuzzy analytical models of damage functional, namely, half depressed distribution, swing distribution, combined swing distribution, by which, fuzzy extension territory on damage evolution is formulated here. With the representation of damage variable β probabilistic distribution as well as formulation on stochastic sub-space of damage variable, expended on the basis of extension criterion and fuzzy probability is damage model defined within generalized uncertain space, by which, introduced is fuzzy probabilistic integral algorithm of generalized uncertain damage variable that could be simulated by the forthcoming fuzzy stochastic damage constitution model based on three fuzzy functional models before. Moreover, in order to realize the joint of fuzzy input and output procedure on generalized uncertain damage variable calculation, fuzzy self-adapting stochastic damage reliability algorithm is, with the update on fuzzy stochastic finite element method within standard normal distribution probabilistic space by the help of foregoing fuzzy stochastic damage constitution model, offered in this paper on the basis of equivalent-normalization and orthogonal design theory.

Fuzzy Reliability Evaluation of a Fire Detector System

Reliability has vital significance to engineers and designers in a safety system. Consequently, failures free operation of components or sub-systems is of their key concern. To assess the reliability of such systems quantitatively, failure data of the components or sub-systems is essentially required. In general, such data is either not pre-recorded or present in linguistic form (good, bad etc). For quantitative evaluation of reliability the usual probabilistic considerations seems to be inadequate. Therefore, in this paper, conventional fault tree analysis (FTA) approach integrated with fuzzy theory has been used to evaluate the reliability of a fire detector system using fuzzy failure possibilities of components (or subsystems).

Fuzzy Reliability Evaluation Base on MTTF as Fuzzy Number

Fuzzy Reliability Evaluation Base on MTTF as Fuzzy Number

A Improvement Analysis Model Based on Fuzzy Parameters Reliability

Fuzzy Structure; Fuzzy Parameters; Reliability; Membership Function Abstract. This paper takes the fuzzy mathematics' reliability analysis as study object, has conducted the research to the fuzzy parameter system's reliability; comparing with traditional reliability analysis, obtained more precise fuzzy reliability confidence interval formula and carried on the proving based on cascade system, which has solved the computation complexity and the low precise problem in the tradition fuzzy reliability analysis's mass fuzzy operation. Method in the paper has certain promotional value in the fuzzy problem's research. It solved some problems such as the traditional fuzzy reliability analysis in the mass caused by the calculation of fuzzy computing complexity and low-precision. The emphasis of the article is divided into two parts: One is analysis and discussion on traditional module reliability analysis method and the fuzzy number membership function; the other one is proposing one new fuzzy parameter reliability analysis method and the conclusion, based on the former analysis.

Analysis on Draghead Teeth of Drag Suction Hopper Dredgers Based on the Theory of Fuzzy Reliability

Drag suction hopper dredger is dredg the hard compacted soil,dreghead teeth intensity will lead to an undersized cutting depth and a large cutting resistance, it raise failure probability. In this paper, investigate the relation between dredging depth，width,resistance and draghead teeth reliability influenced under different conditions,including various teeth,loads,navigating speeds and high-pressure jets.Discussed their effects on cutting depth,width and resistance.At last this paper obtain the reliability index and failure probability of the draghead teeth through the calculation numerical example.In this example,the method improvements efficiency for Draghead Teeth based on analysis on reliability.

The Fuzzy Reliability Robust Design Based on MATLAB

In order to rationalize the design of the worm-drive, the fuzzy reliability design method and robust design method were fully applied to develop the new model for fuzzy reliability optimization design of worm-drive with the minimum weight, minimum sliding-velocity, and minimum sensitivity as the objective function. The fuzzy optimization design result of the worm-drive was obtained by compiling MATLAB procedure. Compared with traditional design methods，the center distance was reduced by 33.3％, the sliding speed is reduced by 10.6%.The life of the worm-drive was raised by11.5％,and the wear quantity of the worm-drive was decreased by 0.1％after 100 hours' running.