QUANTITATIVE ASSESSMENTS OF SYSTEM RELIABILITY

Abstract

This paper is a report of an article by A. E. Green “Quantitative assessments of system reliability”. The paper extensively introduces the article by introducing the background, stating the motivation and objectives as well as giving a summary of the article. The work then explains the work presented in the article, discusses the contributions and also discusses the deficiency and potential improvements.

INTRODUCTION

System reliability refers to the continuity of correct service of a computer system for a specified period under all the relevant conditions. Reliability requirements for a system often evolve from the original problem definition and get described through criteria developed from the feasibility analysis, from operational requirements and the maintenance concept, and also from identification and prioritization of technical performance measures. The applications of system reliability include risk analysis, environmental protection, ensuring quality, engineering design, and optimization of maintenance and operation. The report focuses on explaining quantitative assessments of system reliability paper, identifying its contributions as well as determining its deficiencies and the possible dimensions of improvements through the critical review process of the work. The article examines the uses, reliability techniques and benefits in a plant system. The report begins by examining the work done. It then identifies and highlights the contributions of quantitative assessments of system reliability in various disciplines. It then identifies the deficiencies of the work and develops possible improvements that can get undertaken of the work.

Nomenclature

f(x) = the density function for the variability of performance of the equipment in time.

R = the performance level required that should not get exceeded

P = the probability of complete failure of the equipment

ARTICLE I

In the fields of safety, various professionals have found it necessary to quantify a reliability requirement in some manner. They include personnel working in aircraft and nuclear reactors. Abnormal circumstances can necessitate for the provision of highly reliable ways of safeguarding self. Failure of the proper operation of the protective system may result in a hazardous safety compromise. Reliability is thus significant, and its evaluation should get undertaken in the early stages of the design. When evaluating the reliability of a system, it is essential to demonstrate that it can operate at least once under one set of conditions both in space and time. An attempt gets made to make a probabilistic statement about the variability and complete failure of the equipment in the general form.

The variability of failure of performance of a system manifests itself in different ways namely change in performance of equipment and the complete catastrophic failure that allows no operation at all. The changes in performance of equipment can get revealed inherently by the design of the equipment as well as the use of special monitoring facilities or special testing procedures. The figure below shows some design estimate of performance concerning the variability that extends through the entire spectrum of performance.

Figure 1: performance, achievement and requirement (source: Green, 1971)

The variations in performance demonstrate that the performance values are more likely to happen near to the design estimate or in the catastrophic failure region. Superimposed upon the pattern there is a requirement shown as R, but itself may also get distributed in time and space. Through carefully considering the forms of requirement and the attained performance it may get found that quite simple models of reliability may be acceptable.

The techniques for the preparation of a probabilistic model are generic, and it is essential to understand the exact problem that is getting solved. Although the probabilistic model may get developed, it is important to put into consideration the kind of data available to feed into the model.

The reliable and safe operation of a plant often relies upon the functioning of different systems as well as in the design of various decisions that get required upon the configuration of the systems. The specific approach that gets chosen should get considered to have access to some organized bank of reliability data. Plant systems are different among industries; however, similar equipment and similar configurations get observed, and many of the environmental stressing conditions are usually similar. The reliability techniques used are generic, however; their application gets altered according to whether an individual is considering hazard evaluation or availability. In the assessment of a system, it is necessary to commence with an assessment of the inherent ability of the system to function. Different components and equipment in a plant system fail at different rates. They include bellows, gaskets, diaphragms metal, springs, unions and junctions strip chart recorder, pressure switch, nut and bolt, three phase oil filled transformer, diesel engine, centrifugal pump, overhead transmission line, and many others. The kind of testing and maintenance get undertaken by a system requires to get considered and times specified for periodic testing and time to repair.

2. CONTRIBUTIONS OF ARTICLE

The article makes significant contributions to ensuring a safe and reliable environment in different industries and plants. The article discusses the importance of incorporating a reliability system so as to ensure the proper functioning of devices for a specified period under normal circumstances. The paper also discusses the aspects of the prediction of the reliability of protective systems using quantified reliability techniques. The article also emphasizes the importance of testing and monitoring facilities.

2.1 Deficiency and Potential Improvements

The article does not specify the failure modes that exist for different systems, plants, and industries. Different plant systems often encounter different challenges; hence, it would be difficult to identify the particular problems associated with different plant systems. As a potential improvement to the article, specific problems in specific common systems would get covered so as to assist reliability analysts.

Summary

The article comprehensively examines the need to evaluate with the minimum of subjectiveness, the need for reliability systems in the design and operation of a plant in various fields of application. The article emphasizes the importance of ensuring a safe and reliable plant.

References

Green, A. E. (1971). Quantitative assessments of system reliability. In Fourth Symposium on Chemical Process Hazards with Special Reference to Plant Design, University of Manchester Institute of Science and Technology.

Rausand, M., & Høyland, A. (2004). System reliability theory: models, statistical methods, and applications (Vol. 396). John Wiley & Sons.

Sherry Roberts is the author of this paper. A senior editor at MeldaResearch.Com in research paper services if you need a similar paper you can place your order for professional research proposal writing services.