焊接H形截面钢柱板组弹塑性相关屈曲和容许宽厚比

Elasto-plastic interactive buckling and allowable width-thickness ratios of plate assembly in welded H-section steel columns

建立了竖向轴压力和单调水平荷载作用下焊接H形截面悬臂钢柱板组弹塑性相关屈曲的有限元分析模型,通过改变轴压比、翼缘宽厚比、腹板高厚比及翼缘-腹板厚度比等参数,对非特厚实截面钢柱进行几何非线性和材料非线性有限元分析.然后,基于分析结果,利用最小相对误差拟合法得到极限弯矩比的实用计算公式.最后,基于整体-局部等稳原则导出板组容许宽厚比相关曲线方程,并通过算例对容许宽厚比相关曲线与钢结构设计规范的翼缘和腹板宽厚比限值曲线进行比较.结果表明:构件长细比较小时,规范规定的翼缘和腹板宽厚比限值可能超出容许宽厚比相关曲线限定的范围;翼缘宽厚比与腹板高厚比限值相关,并且两者均随轴压比、翼缘-腹板厚度比、构件长细比、塑性发展系数的变化而变化.

The finite element analysis model was built for the elasto-plastic interactive buckling of plate assembly in a welded H-section cantilevered steel column subjected to the vertical axial compressive force and the horizontal monotonic shear force. A series of geometrical and material nonlinear finite element analyses for steel columns with non-plastic sections were carried out by varying the axial compression ratio,the flange width-thickness ratio,the web height-thickness ratio,and the flange-web thickness ratio. Then,the practical formula of the ultimate moment ratio was obtained by the minimum relative error fitting algorithm based on the analysis results. Finally,the equation for the allowable width-thickness ratio correlation curves of plate assembly was derived on the basis of the principle of simultaneous overall and local interactive buckling. And the allowable width-thickness ratio correlation curves were compared with the flange and web width-thickness ratio limitation curves according to Code for Design of Steel Structures. The results showthat the width-thickness ratio limitations of the flange and the web according to the code may exceed the regions enclosed by the allowable width-thickness ratio correlation curves when the slenderness ratio is small. The flange width-thickness ratio is relative to the web height-thickness ratio limitations,and both of them vary with the changes of the axial compression ratio,the flange-web thickness ratio,the member slenderness ratio,and the plasticity development coefficient.