矩形钢管混凝土壁板的屈曲后强度

为研究矩形钢管混凝土壁板的屈曲后强度，根据平板的弹塑性屈曲理论并考虑残余应力的影响，确定了板件发生塑性屈曲、弹塑性屈曲和弹性屈曲的正则化界限宽厚比。采用试验验证的有限元模型进行了宽厚比为20~150、钢材屈服强度为275~960 MPa的矩形钢管混凝土壁板局部屈曲分析，以界限宽厚比为控制点，根据有限元结果拟合出了矩形钢管混凝土壁板的有效宽度计算式。研究结果表明：弹性屈曲板件的屈曲后强度提高程度显著高于弹塑性屈曲板件；屈曲后强度的提高程度与钢材屈服强度无明显相关性；与无面外约束钢板相比，混凝土的单侧约束作用可使板件的屈曲后强度普遍提高约50%；提出的矩形钢管混凝土壁板的正则化界限宽厚比和有效宽度计算式与试验结果吻合较好，有效宽度试验值比所提公式计算值平均增大7.2%，标准差为0.091。

Post-buckling strength of rectangular concrete-filled steel tube panels

To study the post-buckling strength of rectangular concrete-filled steel tube (CFST) panels, according to the elastic-plastic buckling theory of plates and considering the influence of residual stress, the regularized boundary width-to-thickness ratio of plastic buckling, elastic-plastic buckling and elastic buckling was determined. The finite element model validated by the tests data was used to analyze the local buckling of the rectangular CFST panels with width-to-thickness ratio of 20-150 and steel yield strength of 275 MPa-960 MPa. Taking the boundary width-to-thickness ratio as the control point, the effective width formula of rectangular CFST panels was fitted with the finite element results. The results show that the post-buckling strength of elastic buckling plates is significantly higher than that of elastic-plastic buckling plates, and there is no significant correlation between the increase of post-buckling strength and the yield strength of steel. Compared with the steel plate without out-of-plane restraint, the unilateral restraint of concrete can increase the post-buckling strength of plates by about 50%. The width-to-thickness ratio limits and the effective width formula of rectangular CFST panels proposed in this paper are in good agreement with the experimental results. The experimental value of effective width is 7.2% larger on average than that calculated by the formula in this paper, and the standard deviation is 0.091.