关键词: 不确定系数, 结构可靠度, 轻量化设计, 多分区, 全机结构

Abstract: The quantification of the aircraft uncertainty factor in the development of new aircraft poses a significant challenge, primarily due to the lack of established design experience and relevant test data for novel configurations. This paper proposes a new design methodology for determining the aircraft uncertainty factor to address this issue. The proposed method aims to overcome the inherent conservatism of traditional design approaches, which employ a single, unified uncertainty factor for the entire aircraft, and resolves the conflict between universality and computational efficiency encountered in existing structural reliability algorithms. This enables a more precise and lightweight aircraft structural design. Grounding the approach in structural reliability design criteria, a novel hybrid reliability algorithm is introduced that integrates the First-Order Second-Moment (FOSM) method with the Monte Carlo (MC) method. This hybrid strategy is designed to maintain the broad applicability of the MC method while significantly enhancing its computational efficiency. Leveraging this algorithm, the uncertainty factor is determined through an inverse process based on calculated structural reliability. Furthermore, a partitioned design strategy for the entire airframe is established. This strategy involves dividing the aircraft into multiple distinct segments, where dedicated, zone-specific uncertainty factors are computed according to the unique characteristics of each segment, including material properties, load conditions, and manufacturing processes. This replaces the conventional use of a single global factor. Finally, the implementation process of the proposed methodology is comprehensively demonstrated through detailed case studies of a wing structure and a full aircraft model. The results confirm that the method effectively computes distinct uncertainty factors for different structural regions. Consequently, it provides a quantitative basis and a viable technical pathway for achieving a lightweight design for the entire aircraft structure without compromising structural reliability.

Key words: Uncertainty Factor, Structural Reliability, Lightweight Design, Multi-Zone, Entire Aircraft Structure