A novel approach based on triangular pendant hesitant fuzzy set for RAM analysis of repairable systems

The current study presents a new approach based on Triangular Pendant Hesitant Fuzzy Set (TPHFS) for Reliability, Availability and Maintainability (RAM) analysis of repairable systems. For this purpose, the definition of TPHFS and the arithmetic operations between two triangular pendant hesitant fuzzy numbers (TPHFNs) are introduced. The proposed approach is divided into two phases. In the first phase, TPHFNs are used to identify and represent uncertainties in the data related to components' failure rate (λ) and repair rate (μ). Thereafter, fuzzy expressions based on TPHFNs are developed for the λ and μ of systems connected in series and parallel configurations. In the second phase, reliability, availability and maintainability of repairable systems are obtained for system analysis. Also, to identify the most critical component of the system, a RAM-index based on TPHFNs is developed. For illustration purposes, the turbine generator system of a thermal power plant has been taken.