IIE Transactions · 2001 · 244 citations · 22 references
EngineeringSystems EngineeringFault ToleranceFault-tolerant SystemsSystems ProgrammingHigh AvailabilityRedundancy ManagementRedundancy PlanningReliability ModelingReliability-based DesignReliable System DesignCold Standby RedundancyCold Standby SystemsOptimal DesignRedundancy AllocationRedundancy DesignReliability OptimizationSeries-parallel RedundancySystem Reliability
Nonrepairable series‑parallel systems with cold‑standby redundancy have traditionally relied on exponential failure and perfect switching assumptions, making optimal design difficult when component hazards vary and switching is imperfect. The study aims to determine optimal design configurations for such systems by selecting components to maximize system reliability. The authors formulate the problem as an integer program using Erlang‑distributed component lifetimes and solve it via an equivalent optimization formulation to identify optimal redundancy allocations. The proposed method outperforms existing algorithms by more accurately modeling cold‑standby redundancy and is validated on a large 14‑subsystem problem.
Abstract A solution methodology is described and demonstrated to determine optimal design configurations for nonrepairable series-parallel systems with cold-standby redundancy. This problem formulation considers non-constant component hazard functions and imperfect switching. The objective of the redundancy allocation problem is to select from available components and to determine an optimal design configuration to maximize system reliability. For cold-standby redundancy, other formulations have generally required exponential component time-to-failure and perfect switching assumptions. For this paper, there are multiple component choices available for each subsystem and component time-to-failure is distributed according to an Erlang distribution. Optimal solutions are determined based on an equivalent problem formulation and integer programming. Compared to other available algorithms, the methodology presented here more accurately models many engineering design problems with cold-standby redundancy. Previously, it has been difficult to determine optimal solutions for this class of problems or even lo efficiently calculate system reliability. The methodology is successfully demonstrated on a large problem with 14 subsystems.
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