RELIABILITY ENGINEERING: OLD PROBLEMS AND NEW CHALLENGES E. Zio Dept. of Energy, Polytechnic of Milan, Via Ponzio 34/3, 20133 Milan, Italy Phone: +39-2-2399-6340; fax: +39-2-2399-6309 E-mail address:
[email protected] Abstract The first recorded usage of the word reliability dates back to the 1800s, albeit referred to a person and not a technical system. Since then, the concept of reliability has become a pervasive attribute worth of both qualitative and quantitative connotations. In particular, the revolutionary social, hal-00610053, version 1 - cultural and technological changes that have occurred from the 1800s to the 2000s have contributed to the need for a rational framework and quantitative treatment of the reliability of engineered systems and plants. This has led to the rise of reliability engineering as a scientific discipline. In this paper, some considerations are shared with respect to a number of problems and challenges which researchers and practitioners in reliability engineering are facing when analyzing today’s complex systems. The focus will be on the contribution of reliability to system safety and on its role within system risk analysis. Keywords: Reliability engineering, Safety, Risk Analysis, Uncertainty, Complex Systems 1 1 Introduction This paper collects a number of considerations on problems and challenges of current reliability engineering research, that were shared during the keynote lecture by the author at the European Safety and Reliability Conference ESREL 2007 held in Stavanger (Norway) in 2007. The focus on reliability engineering is with respect to its role within the current developments of system safety and risk analysis. The focus on the problems and challenges relates to the representation and modeling of the complexity of the systems, to the quantification of the system models and to the proper representation, propagation and quantification of the uncertainty in the system failure behavior and model. The focus on the research for techniques and methods to address such problems and challenges is strongly biased towards the new computational developments continuously stimulated by the constantly increasing computing power and capabilities. hal-00610053, version 1 - The author apologizes at the forefront for the incapability of treating the subject exhaustively, with the deserved completeness of material and references and with the due profundity: seeking such objectives would have rendered overwhelming the task of writing the paper… as well as that of reading it. Reliability is a fundamental attribute for the safe operation of any modern technological system. Focusing on safety, reliability analysis aims at the quantification of th