高强冷弯薄壁型钢轴压柱畸变屈曲研究

550MPa高强冷弯薄壁型钢卷边槽形截面轴压柱发生畸变屈曲时会出现三种模式（O—O，O-I，I—I），考虑材料和几何双重非线性的有限元法对三种畸变屈曲模式的构件承载力、变形模式、畸变屈曲应力、横截面应力的分布等相关性能进行比较分析，可看出三种畸变屈曲模式诸性能存在较大不同，同时畸变屈曲与局部屈曲、整体屈曲在相关性能方面也存在不同。采用直接强度法对畸变屈曲轴压柱极限承载力进行计算，计算结果与试验结果较吻合，故在计算畸变屈曲轴压柱极限承载力时建议采用直接强度法．

DISTORTIONAL BUCKLING BEHAVIOR OF HIGH STRENGTH COLD-FORMED STEEL COLUMNS SUBJECTED TO AXIAL COMPRESSION

550 MPa high strength cold-formed steel lipped channel column under axial compression loading has three modes （O-O,O-I,I-I） when distortional buckling occur. The distortional buckling behavior of three different modes has been analyzed by finite element method （FEM） which consider geometric and material non-linear, including load carrying capacity, deformation, stress of distortional buckling, stress distribution of cross-section. Analysis results show that behavior of different distortional buckling modes has a greater different in many respects. At the same time distortional buckling is different from local buckling and overall buckling in some behaviors. The direct strength method （DSM） has been used to predict the ultimate load capacity of distortional buckling. The comparison between test results and analysis results shows that result calculated by the direct strength method is close and conservative to test results. So the direct strength method has been suggested to calculate distortional buckling ultimate load capacity of channel columns under axial compression.