Time-variant reliability-based robust design optimization (TRBRDO) has achieved certain progress recently for its ability to ensure both robustness of design and feasibility of time-variant probabilistic constraints. However, the existing TRBRDO methods have not specifically addressed the dynamic uncertainty of material degradation, and there is lack of a universal and efficient approach for this class of time-variant robust design problems. For this reason, this paper proposes three solution strategies, namely the reliability index based double-loop method, performance measure based double-loop method, and sequential single-loop method. In these approaches, the minimum reliability of each time-variant probabilistic constraint is considered by obtaining the extremum in a series system. With use of the first-order reliability analysis technique, two different single-loop multivariate optimization models are established to obtain the minimum reliabilities and minimum performance measures through sequential quadratic programming algorithm, respectively. Following this, two different double-loop models and a sequential single-loop model are developed. Furthermore, an augmented step length adjustment technique is proposed for inverse reliability analysis, which is integrated into the performance moment integration and percentile difference method to derive the robustness indicators for the design objective. Finally, three illustrative numerical examples and one engineering problem are provided to demonstrate the effectiveness of the proposed solution strategies for reliable and robust design optimization with high computational efficiency.

中文翻译：

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基于时变可靠性的稳健优化，适用于材料降解的结构


基于时变可靠性的鲁棒性设计优化 （TRBRDO） 在确保设计的鲁棒性和时变概率约束的可行性方面最近取得了一定的进展。然而，现有的 TRBRDO 方法并没有专门解决材料降解的动态不确定性，并且缺乏一种通用且有效的方法来解决这类时变鲁棒设计问题。为此，本文提出了三种求解策略，即基于可靠性指数的双环法、基于性能度量的双环法和序贯单环法。在这些方法中，通过获取级数系统中的极值来考虑每个时变概率约束的最小可靠性。利用一阶可靠性分析技术，建立了两种不同的单环多元优化模型，分别通过顺序二次规划算法获得最小可靠性和最小性能度量。在此之后，开发了两种不同的双环模型和一种顺序单环模型。此外，提出了一种用于逆可靠性分析的增强步长调整技术，该技术被集成到性能矩积分和百分位数差异方法中，以推导出设计目标的鲁棒性指标。最后，提供了三个说明性数值示例和一个工程问题，以证明所提出的求解策略在可靠和鲁棒的设计优化以及高计算效率方面的有效性。