Comparison of some reliability characteristics between redundant systems requiring supporting units for their operations

Abstract

In this paper, two different systems both are requiring a supporting unit for their operation are studied. The first system consist of 3-out-of-4 subsystem requiring its support from 2-out-of-4 subsystem for its operation while the other system is  two unit cold standby system where each unit is attached to its supporting unit for its operation. Each system is attended by two repairmen, one repairing the main unit and the other repairing the supporting unit. Explicit expressions for mean time to system failure (MTSF) and steady- state availability are developed. We analyzed the system by using linear differential equations. Effect of failure and repair rates on mean time to system failure and steady-state availability have also been discussed graphically. Comparisons are made graphically for specific values of parameters. Furthermore, we compare these reliability characteristics for the two models and found that model I is more reliable and efficient than the remaining models.