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  • A new risk prioritization model for reliability assessment in design phase of new products 
    Publication . Sá, Bruno Ricardo Sousa de; Anes, Vitor Manuel Rodrigues; Rodrigues, Pedro Carmona
    Nowadays, companies take very seriously the subject of product quality, and make great efforts to guarantee that a reliable product is deployed into the market. Early detection of product faults is less costly and easier to correct. Therefore, companies tend to proceed with reliability tasks along all product development stages, such as Failure Modes and Effects Analysis (FMEA) which is a well-known tool used to identify failure modes and thus enhance system reliability through the development of suitable correction actions. Few companies have the resources to tackle all failure modes so they resort to prioritization methodologies in order to focus on the most critical ones. The most commonly prioritization methodology used worldwide is the Risk Priority Number (RPN). However, it has been raised by scientific community awareness towards RPN shortcomings that may result in misleading prioritization outcomes. Despite all the critics, conventional RPN is still utilized worldwide for prioritization of failure modes, probably due to its simplicity. In this study, it is proposed an alternative computation model (RPN beta - RPNb) for risk prioritization, which attempts to maintain application simplicity while eliminating some of conventional RPN shortcomings – 1) No consideration of risk drivers’ relative importance, 2) repetition of RPN values through different risk drivers’ combinations, 3) non-continuity of RPN values scale, and 4) high sensitiveness to variations in risk drivers scoring. Companies cannot rely on ineffective methodologies to support the decision-making, and implementation of corrective action for reliability improvement is not an exception. It is of utmost importance to replace the utilization of conventional RPN for failure modes prioritization. Based on a comparative analysis of a case study, RPNb presents itself as an apparently robust alternative, capable of delivering sustained results, adjustable to industry/area specific characteristics, through a straightforward computation mode.
    2017-09-15Master thesis Open access Show more