The evolution of system reliability optimization

System reliability optimization is a living problem, with solutions methodologies that have evolved with the advancements of mathematics, development of new engineering technology, and changes in management perspectives. In this paper, we consider the different types of system reliability optimization problems, including as examples, the redundancy allocation problem (RAP), the reliability allocation problem and the reliability-redundancy allocation problem (RRAP), and provide a flow of discussion and analysis on the evolution of the approaches for their solutions. We consider the development and advancement in the fields of operations research and optimization theory, which have allowed the formalization and continuous improvement of the methods and techniques to address reliability design problems of even very complex systems in different technological domains. Technological advances have naturally brought changes of perspectives in response to the needs, interests and priorities of the practical engineering world. The flow is organized in a structure of successive “Eras of Evolution,” namely the Era of Mathematical Programming, the Era of Pragmatism, the Era of Active Reliability Improvement. Insights, challenges and opportunities are highlighted.