Analysis Of Redundant Systems Research Articles

Reliability Modelling and Analysis of Redundant Systems Connected to Supporting External Device for Operation Attended by a Repairman and Repairable Service Station

In this paper, probabilistic models for three redundant configurations have been developed to analyze and compare some reliability characteristics. Each system is connected to a repairable supporting external device for operation. Repairable service station is provided for immediate repair of failed unit. Explicit expressions for mean time to system failure and steady-state availability for the three configurations are developed. Furthermore, we compare the three configurations based on their reliability characteristics and found that configuration II is more reliable and efficient than the remaining configurations.

Application of Sedyakin’s model and Birnbaum-Saunders family for statistical analysis of redundant systems with one warm stand-by unit

The purpose of this paper is to determine the improve system reliability by introducing the redundancy of components. This paper considers one warm stand-by unit with one main unit. We study the reliability of such systems using probability models in terms of Sedyakin’s model. A parametric family of Birnbaum-Saunders distributions is considered as the distribution of failure times both of main and stand-by units. Parametric point and interval estimation is obtained from censored data. Bibliography: 17 titles.

Improved seismic fragility modeling from empirical data

The improved empirical fragility model addresses statistical dependence among observations of seismic performances, which arises from common but unknown factors influencing the observations. The proposed model accounts for this dependence by explicitly including common variables in the formulation of the limit state for individual components. Additionally, the fact that observations of the same component during successive earthquakes are correlated is considered in the estimation of the model parameters. As demonstrated by numerical examples considering the fragility of electrical substation equipment, the improved formulation can lead to significantly different fragility estimates than those obtained with the conventional assumption of statistical independence among the empirical observations. Furthermore, the conventional approach underestimates the statistical uncertainty associated with the resulting fragility estimates. The paper concludes with an investigation of the effects of statistical uncertainty and component statistical dependence on the system fragility. Numerical examples demonstrate that these effects are significant and must be addressed in the analysis of redundant systems.

A design diversity metric and analysis of redundant systems

Redundant systems are designed using multiple copies of the same resource (e.g., a logic network or a software module) in order to increase system dependability. Design diversity has long been used to protect redundant systems from common-mode failures. The conventional notion of diversity relies on independent generation of different implementations. This concept is qualitative and does not provide a basis for comparing the reliabilities of two diverse systems. In this paper, for the first time, we present a metric to quantify diversity among several designs and illustrate its effectiveness using several examples. Applications of this metric in analyzing reliability and availability of diverse redundant systems, and deriving simple relationships between diversity, system failure rate, and mission time are also demonstrated.

Using Spice Circuit Simulation Program in Reliability Analysis of Redundant Systems with Non-Repairable Units and Common-Cause Failures

The effectiveness of Simulation Program with Integrated Circuit Emphasis (SPICE) in calculating probabilities, reliability, steady-state availability and mean-time to failure of redundant systems with non-repairable units and common-cause failures described by Markov models is demonstrated. General equations and procedure for constructing the equivalent circuit forNparallel units are presented. Results obtained, forN=1,2,3, using SPICE are compared with previously published results obtained using the Laplace transform method. Full SPICE listings are included.

Failure rate coupling effects in uncertainty analysis of redundant systems

Abstract A simple method is described for deriving system failure probability distributions from component failure rate uncertainties which obey either gamma or log normal distributions. The formalism is applicable to series-parallel systems and includes the effects of coupling between the failure rates of individual components. Coupling means that the failure rates of identical components under the same conditions scatter significantly less than the failure rates of just any two components of the same type. Examples are used to illustrate that there are various interpretations for the coupling phenomenon and alternative ways to use observed failure data in reliability and uncertainty analysis. Both the mean value and the variance of the distribution of the failure probability of a redundant system tend to increase with increasing coupling.

Critical and non-critical human error modelling in redundant systems: modified block diagram approach

Abstract Three newly developed models are presented for performing reliability analysis of redundant systems with erlangian-distributed critical and non-critical human error times. Parallel, k-out-of-n and parallel-series configurations are analysed. System reliability, mean time to failure, time-to-failure variance, failure density function formulae, and hazard rate function formulae are developed. Selective plots are shown to demonstrate the effect of varying critical and non-critical human errors.

Analysis of redundant systems with human errors : Balbir S. Dhillon and S. N. Rayapati. Proc. a. Reliab. Maintainab. Symp. 315 (1985)

Analysis of redundant systems with human errors : Balbir S. Dhillon and S. N. Rayapati. Proc. a. Reliab. Maintainab. Symp. 315 (1985)

Probabilistic analysis of redundant systems with human errors and common-cause failures

This paper presents two mathematical models representing three unit redundant systems with common cause failures and human errors. Reliability, steady state availability, mean time to failure (MTTF) and variance of time to failure formulas are developed for both models. Supplementary variables and Markov techniques were employed to obtain the resulting expressions. Reliability, availability, failure probability and MTTF plots are .shown

Analytical and numerical unavailability analysis of redundant systems with dependent human error

This paper discusses a theoretical and numerical investigation of dependent human error on the failure probability of the redundant system tested periodically. Two methodologies of calculating the failure probability are developed. One is developed using the modified Karnaugh map and it can analytically compute the failure probability of the simple system. The other is developed using the minimal cut set and it gives the conservative solution. However, this method can be easily applied to the complicated system without making significant errors.

Some notes on the analysis of redundant systems by means of the conception of conservation of energy

The principles of the analysis of conservative redundant systems capable of deformation are considered. It is well known that reference both to the conditions for equilibrium and geometrical compatibility is necessary to enable a unique solution to be obtained in a particular case.The setting up of one or other of these conditions in a general case using the concept of energy is discussed with reference to the law of conservation of energy.The use of “complementary energy” for the fulfillment of the conditions for geometrical compatibility is demonstrated. The direct application of the conditions of equilibrium and geometrical compatibility is considered in an appendix.