EVALUATION OF SOME RELIABILITY METRICS OF A STANDBY THREE-UNIT SYSTEM
2026 Volume 17
Sa’adu, S.,,Department of Mathematics, Federal University, Dutse, Nigeria
Yusuf, B.,,Department of Mathematics, Federal University, Dutse, Nigeria
Ali, U. A.,,Department of Mathematics, Federal University, Dutse, Nigeria
Usman, A. U,,Department of Mathematics and Statistic, Yobe State University, Damaturu, Nigeria
Abstract:
engineering design, especially in applications where continuous operation is required. This
study focuses on a three-unit standby system, in which two identical units operate
simultaneously while the third remains in standby to improve fault tolerance. The objective is
to evaluate key reliability metrics such as Steady state availability, Busy period, profit and
mean time to failure (MTTF). To achieve this, a continuous-time Markov chain (CTMC)
approach is employed, incorporating the system’s transition dynamics under both active and
standby configurations. Explicit expressions are derived for the reliability indices, and
numerical illustrations are provided to highlight the system’s performance under varying
failure and repair rates. The results demonstrate that the standby unit significantly enhances
the system’s dependability by prolonging operational lifetime and improving availability
compared to non-redundant configurations. The study concludes that such a configuration is
suitable for mission-critical applications where downtime must be minimized. The findings
provide valuable insights for system designers, particularly in optimizing redundancy and
repair strategies for cost-effective and resilient engineering systems
Keyward(s): Availability, Busy period, Mean time failure, And Reliability
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