考虑载荷及强度不确定性的结构安全系数精细化设计方法

doi:10.3901/JME.2024.13.182

摘要/Abstract

摘要： 受制造加工以及服役环境影响，结构强度和所受载荷均存在较强不确定性。为保证结构安全，工程中常采用安全系数来抵御多源不确定性的影响。然而，现有安全系数设计方法大多基于工程经验或者简化理论模型，难以准确量化结构失效风险，致使结构设计过度冗余。因此，提出了一种面向载荷和强度不确定性的结构安全系数精细化设计方法，通过建立基于一阶可靠性方法的全局可靠度优化框架近似构建了失效概率与安全系数的区间映射关系。进一步，提出了基于单变量降维法的安全系数修正策略并通过构建关心域精细化Kriging模型，实现安全系数区间的高效、精准估计，有效平衡了结构轻量化与高可靠性的矛盾。数学算例和典型航天加筋筒壳算例验证了本方法的有效性和工程适用性。

关键词: 安全系数, 可靠度优化, 航天结构, 区间估计

Abstract: Structural strength and load are subject to high uncertainties due to manufacturing as well as the service environment. To ensure structural safety, safety factors are generally utilized to resist the influence of multiple sources of uncertainties in engineering structures. However, most of the existing safety factor design methods are based on engineering experience or simplified theoretical models, which are difficult to accurately quantify the risk of structural failure. This will result in excessive redundancy in structural design. Therefore, a precise design method for structural safety factor considering strength and load uncertainty is proposed. Therein, an interval mapping relationship between the failure probability and the safety factor is approximately obtained by establishing a global reliability optimization framework based on the first-order reliability method. Furthermore, a safety factor correction strategy based on the univariate dimension-reduction method is also proposed. And then by constructing a high-precision kriging model in the concerned search region, an efficient and accurate estimation of the safety factor interval is achieved, which effectively balances the contradiction between structural lightweight and high reliability. Finally, a mathematical example and a typical aerospace stiffened cylindrical shell example are employed to verify the effectiveness and engineering applicability of the proposed method.

Key words: safety factor, reliability-based design optimization, aerospace structures, interval estimate

中图分类号:

TB114.3
V11

郝鹏, 杨浩, 陈发鑫, 曾耀祥, 王明杰, 王博. 考虑载荷及强度不确定性的结构安全系数精细化设计方法[J]. 机械工程学报, 2024, 60(13): 182-192.

HAO Peng, YANG Hao, CHEN Faxin, ZENG Yaoxiang, WANG Mingjie, WANG Bo. A Precise Design Method for Structural Safety Factor Considering Load and Strength Uncertainty[J]. Journal of Mechanical Engineering, 2024, 60(13): 182-192.

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