A Precise Design Method for Structural Safety Factor Considering Load and Strength Uncertainty

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. © 2024 Chinese Mechanical Engineering Society. All rights reserved.