Failure Mode and Effect Analysis (FMEA) of Vertical Axis Wind Turbine

FMEA is a widely used risk assessment tool for defining, identifying, and eliminating potential failures in a product, process, design, and services. Previous research efforts have focused on FMEA of Horizontal Axis Wind Turbines but not on the Failure Analysis of Vertical Axis Wind Turbines. This research aims at enhancement of reliability of vertical axis wind turbines using Failure Mode and Effect Analysis (FMEA) method. A total of 12 probable failure modes have been identified, quantified and prioritized based on FMEA. The list of failure modes are ranked according to the assigned Risk Priority Number (RPN), where the higher the RPN value indicates the higher rank of criticality for the related failure mode. Furthermore, based on the obtained results, a disposition and type of required maintenance activity is suggested for critical failure modes. For analysing, evaluating, and prioritizing of failure modes in vertical axis wind turbine, two main approaches of FMEA (i.e. traditional Risk Priority Number (RPN) approach, Fuzzy Logic (FL), and Dempster-Shafer (D-S) theory), the DS theory has been applied to accommodate the diversity of opinions and taking into account the effects of uncertainty in decision making, and the criticality of the components of system is compared using the aforementioned approaches. In traditional RPN, the risk factors of the system failure modes, Severity (S), Occurrence (O), and Detection (D) are scored and by multiplying of S, O, and D, the RPN value is determined. The crisp RPN approach has been criticised to have several deficiencies and for overcoming of shortcomings, the if-then rules of fuzzy logic have been developed for the system expressed in trapezoidal and triangular fuzzy membership functions; and to account for the uncertainty level of the system evaluation and analysis, D-S theory based on three experts’ opinions (multi-criteria decision making) has been applied to the system as well, and finally the obtained results in every approach are compared together. The proposed method accounts for the uncertainty, and the lack of knowledge and experience of the FMEA team.