基于缺陷敏感度的加筋短板承载能力

加筋短板以其高比强度成为飞机结构的基本元素，其设计方法是基于传统的Euler柱屈曲理论和Timoshenko板壳弹性稳定性理论，由于进行了假设和简化，不能很好地预测破坏载荷。采用GMNIA（Geometrically and Material Nonlinear Analysis with Imperfections）分析方法对加筋短板的承载能力进行仿真分析，结果与试验数据吻合良好。基于GMNIA方法开展了不同类型的几何缺陷对加筋短板承载能力敏感度分析，研究了初弯曲、初偏心以及初变形对加筋短板承载能力的影响。给出了表征加筋短板初弯曲和初变形缺陷的计算公式，为有限元模拟加筋短板破坏过程及预测承载能力提供了技术支持。此外，给出了初弯曲下加筋短板承载能力的设计许用值，提出了通过控制加工制造公差量来提高结构极限承载能力的设计建议，具有明确的工程应用意义和实用价值。

Load-carrying capacity of stiffened short plates based on imperfection sensitivity

Stiffened short plates are the basic components of aircraft structure because of their high specific strength. Their design method is based on the traditional Euler column buckling theory and Timoshenko plate shell elastic stability theory. However, the failure load cannot be well predicated due to the assumption and simplification in the design. The load-carrying capacity of the stiffened short plate is simulated by the method of GMNIA (Geometric and Material Nonlinear Analysis with Imperfections), and the results are in good agreement with the experimental data. Based on GMNIA, the sensitivity analysis of different types of geometric imperfections in the load-carrying capacity of the stiffened short plate is carried out. The influence of initial bending, initial eccentricity and initial deformation on the load-carrying capacity of the stiffened short plate is studied. The calculation formulas of the initial bending and initial deformation imperfections of the stiffened short plate are given, providing technical support for the finite element simulation of the failure process and prediction of the load-carrying capacity of the stiffened short plate. Furthermore, the allowable design values of the bearing capacity of stiffened short plates under initial bending imperfection are presented, and suggestions of improving the ultimate bearing capacity in the design by controlling the manufacturing tolerance are put forward, exhibiting engineering application significance and practical value.