| Failure Modes and Effects Analysis (FMEA) is a design tool that mitigates risks during the design phase. Although many industries use the current FMEA technique, it has many limitations and problems. Risk is measured in terms of Risk Priority Number (RPN) that is a product of occurrence, severity, and detection difficulty. Measuring severity and detection difficulty is very subjective. RPN is also a product of ordinal variables, which is not meaningful as a proper measure.; This research addresses these shortcomings and introduce, Lifecycle Cost Based FMEA, which measures risk in terms of cost. The ambiguity of detection difficulty and severity is resolved by measuring these in terms of time loss. Lifecycle Cost Based FMEA is useful for comparing and selecting design alternatives that can reduce the overall lifecycle cost of a particular system. Further, this study applies Monte Carlo simulation to the Lifecycle Cost Based FMEA to account for the uncertainties in: detection time, repair time, occurrence, delay time, and down time. This research compares these three different FMEAs: RPN, Life Cost Based point estimation, and Life Cost Based using Monte Carlo simulation. A case study on a magnet system will show how valuable Lifecycle Cost Based FMEA is in terms of predicting lifecycle failure cost, reliability, availability, and comparing risk and planning preventive and scheduled maintenance.; This research has intrinsic and practical contributions for the design and quality engineering community. Intrinsic contributions are that the methodology allows estimation of lifecycle failure cost of systems, allows engineers to conduct design trade-off analysis based on lifecycle cost, overcame the flaw of risk priority number with conventional FMEA, and the methodology is a probabilistic analysis which has not been considered in this area of research. Some practical contributions include estimation of cost poor quality more effectively, planning for serviceability more systematically, and design comparison in the early design stages which will impact product development decisions. |
