复合板旋转约束刚度推导及箱型结构屈曲分析

基于结构稳定性理论，推导出正交各向异性纤维树脂增强复合材料箱型结构各板连接处旋转约束刚度的近似表达式．与以往的经验公式相比，考虑了材料的正交各向异性和截面尺寸的影响．通过对箱型结构的正交各向异性比、截面属性以及纵横比对旋转约束刚度的影响进行参数研究，验证了旋转约束刚度新公式的精确性和适用范围．通过比较采用不同近似表达式得到的结果与有限元计算结果的对比，表明本文的旋转约束刚度新公式可以更精确地用来计算箱型结构的临界屈曲载荷．

Derivation of Rotational Restraint Stiffness for Discrete Orthotropic Plates and Buckling Analysis of Box Sections

Based on the governing equation of the orthotropic plates, the new explicit formulas of rotational restraint stiffness (k) for discrete orthotropic plates were derived, and they are different from the previous ones which were obtained from the isotropic assumption. The new formulas of the rotational restraint stiffness considering the orthotropic and geometric sectional properties have a considerable application in discrete plate analysis of FRP structural shapes for better accuracy. A case in point is that the new formulas of the rotational restraint stiffness were applied to the local buckling analysis of box-sections. Also conducted was a parametric study that considered the influence of orthotropic ratio, section ratio, and aspect ratio of box-section on the rotational restraint stiffness. The critical local buckling loads were compared with the numerical finite element results, and the present explicit formulas are demonstrated to be more effective in determining the local buckling load of composite box-sectional structures.