Life cycle cost analysis for availability system with parallel components

Two different configurations with parallel components are compared based on their overall availability and life cycle costs under uncertainty in systems lifetime. The time-to-repair and the time-to-failure for each of the primary and parallel components are assumed to have the negative exponential distribution. The unconditional expected present worth of all expenditures during the entire life of the system is obtained using Laplace transform techniques in terms of the initial investment (P), the operating and maintenance costs (C), and the interest rate r. We derive the steady-state availability, AT(∞), and the cost/benefit ratio, , for these two configurations and perform a comparative analysis. Under the cost/benefit criterion, comparisons are made based on assumed numerical values given to the distribution parameters, as well as to the cost components. The configurations are ranked based on: AT(∞) and where is the expected present worth life cycle cost, and B is AT(∞).