初始几何缺陷对翼面结构承载能力影响

Influences of Initial Geometrical Imperfections on Ultimate Bearing Capacity of Wing Structure

加筋板在轴压载荷下的承载能力受初始几何缺陷的影响,故而重构含几何缺陷的有限元模型以及分析缺陷对加筋板前屈曲/后屈曲特性影响均是值得深入研究的问题。为此,采用GMNIA(Geometrically and Material Nonlinear Analysis with Imperfections)方法分析了特征值模态缺陷的幅值、公式表达几何缺陷的形状对加筋板的承载能力的影响,并将承载能力进行了试验校验。研究结果表明:初始几何缺陷通过降低加筋板初始刚度对轴压载荷下加筋板的前屈曲行为有一定的影响,而初始缺陷的显著影响表现在后屈曲段,明显地表现为后屈曲路径和极限承载能力的差异。引入缺陷的加筋板轴压承载能力的有限元计算值与试验值相对误差均小于4.0%。因此,引入特征值模态缺陷和公式表达缺陷的GMNIA分析方法可用于加筋板轴压承载能力的工程设计。

The bearing capacity of stiffened plate under axial compression is influenced by the initial geometrical imperfections.The reconstruction of the FEM with geometrical imperfections and analysis of the influence of imperfections on the pre-buckling and post-buckling characteristics of stiffened plate are worthy of further study.Therefore,GMNA(Geometrically and Material Nonlinear Analysis with Imperfections)method is used to analyze the influence of different eigenvalue mode imperfection amplitudes and formula expression imperfection shapes on load-carrying capacity of stiffened plate,and the results are verified by test.The result show the initial geometrical imperfections seem able to modify the pre-buckling behavior of the stiffened plate under axial compression by a moderate reduction of the initial stiffness,their role appears much more relevant in the post-buckling field,the difference of the post-buckling path and the load-carrying capacity is obvious.The introduction of the imperfection brings the percentage errors between the numerical models and the experimental tests within 4.0%.Therefore,the GMNA analysis method with eigen mode imperfection and formula expression imperfection can be used in engineering design of stiffened plate under axial compression.