考虑翼缘约束的工字形截面腹板的弹性屈曲

摘要

利用有限元方法(FEM)分析了非均匀受压的单块矩形板的弹性屈曲,总结了非均匀受压简支矩形板屈曲系数的各国规范计算公式;在此基础上,改变有限元模型的边界条件,提出了非均匀受压的非加载边固支矩形板的屈曲系数公式.对考虑翼缘嵌固约束作用的工字形截面腹板,指出了翼缘嵌固作用与传统转动弹簧约束的不同,引入翼缘自由扭转刚度和腹板抗弯刚度比值作为无量纲参数,得到了精度良好的考虑翼缘约束作用的非均匀受压腹板的屈曲系数计算公式.验证了传统的弯曲和剪切应力作用下弹性屈曲的相关公式在翼缘弹性嵌固条件下的腹板屈曲问题中的适用性.%Elastic buckling of web plates in I-sections under linearly distributed stresses and shear stresses was investigated using finite element method(FEM). A brief review on various formulas for the buckling coefficients of simply supported plates from different codes was presented firstly. Then the formulas for the plates with two unloaded edges fixed were proposed by changing the boundary conditions of two unloaded edges. The difference between the restraint by the flanges and the traditional rotational restraint was pointed out. A simple and accurate formula for the buckling coefficients of the Web plates restrained by flanges was presented using the ratio of flange's free torsional stiffness to the bending stiffness of the Web as a parameter representing the restraint. A series of finite element analyses of Web plates subjected to combined bending and shear stresses were carried out to validate the applicability of the traditional interaction formula for the buckling of plates under bending and shear.