Reliability optimization through robust redundancy allocation models with choice of component type under fuzziness

Abstract

Due to the inherent uncertainty associated with various factors in the designing stage, considering uncertainty is important in system designs. In this article, a redundancy allocation problem with active strategy and choice of component type is studied where the system engineer faces with insufficient knowledge about exact values of some characteristics of components such as reliability and cost. The impreciseness is considered in terms of fuzzy numbers with triangular and trapezoidal membership functions. To achieve a robust design under different realizations of uncertain parameters, robust models are developed, which is the first attempt in the area of redundancy allocation problems under fuzziness. In worst case, extreme values of uncertain parameters are considered. In the realistic case, the uncertain parameters are dealt with the help of the credibilistic approach of fuzzy programming and the expected value of fuzzy numbers. In other words, the robust model makes a trade-off between the expected value of system reliability as a performance measure, the deviation of system reliability, and the constraint violation where the penultimate one assures the optimality robustness and the last one preserves the feasibility robustness. The proposed models can help system/product designers and managers who are risk-averse to easily deal with the inherent uncertainty in the designing stage. At the end, numerical examples are presented and the results are analyzed.

Cost-oriented component redundancy allocation for a communication system subject to correlated failures and a transmission reliability threshold

“…For convenience, let F denote the set of G satisfying constraints (9) and (11). If S is a d-MS under X, there should exist a G 2 F satisfying constraint (10). Moreover, if S is a d-MS, there exists a G 2 F such that the S is transformed from this G via equation (12)…”

“…Therefore, a system supervisor may also wish to focus on the cost required to satisfy a reliability threshold. 7 In addition, several studies 6,[8][9][10] have shown that the redundancy strategy can maintain and promote the systemic stability. For these reasons, this article extends the previous work of Yeh and Fiondella 4 by searching for the optimal redundancy allocation of binary-state components (i.e.…”

Robust counterpart optimization for the redundancy allocation problem in series-parallel systems with component mixing under uncertainty

“…Mahapatra and Mahapatra [21] considered the problem of minimizing system cost of a series system with the target of system reliability in fuzzy environment and formulated the reliability model as a fuzzy parametric geometric programming problem. Recently, Soltani and Sadjadi [22] presented a robust possibilitic programming approach and developed robust models for RAP with active strategy.…”

Hybrid reliability-based multidisciplinary design optimization with random and interval variables

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