Determining a Methodology for Effective Reliability Program Plans

Reliability is one of the drivers in the design development projects and main objective of this engineering branch is to find methods to assess reliability of equipment or system. Reliability analyses such as Reliability Prediction Analysis, Failure Modes and Effects Analysis (FMEA), Derating (Part Stress) Analysis and Worst Case Circuit Analysis (WCCA) to verify the convenient operation of circuit design are conducted in various Research and Development Projects. The point that requires attention is that all studies or all projects directly focus on Reliability Prediction Analysis, FMEA, WCCA or Derating Analysis separately. This study aims to evaluate all analyses together in a comprehensive manner within a reliability program plan or strategy and to determine overall risk for design project. In addition, with this strategy, the goal of study also is to determine whether the WCCA is required to be applied or not and an algorithm in which cases it will be applied has been established. With this motivation, a new methodology in reliability program plan with a novel understanding of reliability has been implemented and conducted on an example circuit. This implementation has showed that the circuit, which would not be accepted and guaranteed by the analyzes applied by the industry and the literature under normal conditions, was accepted thanks to the proposed unique reliability approach. Possible calendar delay, budget increase or design complexity increase have been prevented.

I. Introduction

Reliability is a key topic of specialty engineering which affects the design decisions of systems. Today, the expectation is from equipment or systems in varied complexity is not only working properly at beginning of lifecycle (the time when they will start to operation), but also expectation from them is to perform the intended function without any failure or unacceptable degradation for the defined time interval till end of lifecycle [1]. Even in case of any failure, system needs to be kept as operational for that stated time interval with several ways and this is called as “Reliability”. In long lifetime programs or in other words for systems that require long usage durations, reliability is the one of the prime considerations in assuring a successful achievement of the strict design goals.