考虑双力矩影响的C型钢梁局部屈曲承载力

Local Buckling Strength of Channel Steel Beam Considering the Influence of Bimoment

对于开口侧作用有偏离剪心的集中荷载的180根C型钢梁进行了有限元模拟,得到C型钢梁的局部屈曲模式、破坏形态及承载力。将有限元模拟结果与按《冷弯薄壁型钢结构技术规范》(GB50018—2002)的有效宽度法计算所得的局部屈曲承载力进行对比分析。结果表明:现行规范有效宽度法计算结果整体上偏于保守,考虑双力矩影响的有效宽度法计算结果与有限元模拟结果更接近但变异系数较大,离散程度较大。基于上述研究进行参数分析,考虑双力矩的影响并提出针对有效宽度法的局部屈曲承载力修正系数公式,修正后局部屈曲承载力与有限元模拟结果较为接近,变异系数较小,离散程度较小。

A finite element simulation was performed on 180 channel steel beams with concentrated loads that deviated from the shear center on the open side.The local buckling mode,failure mode,and strength of the channel beams were obtained.The finite element simulation results were compared with the local buckling strength of the channel beam calculated by the effective width method of Technical Code of Cold-formed Thin-wall Steel Structures(GB50018—2002).It is shown that the calculation results of the effective width method of the current specification are generally conservative.The calculation results obtained by the effective width method considering the influence of the bimoment are closer to the finite element results,but the coefficient of variation and degree of dispersion are larger.Based on the above research,aparametric analysis was carried out.Considering the influence of the bimoment,the formula of the local buckling strength correction coefficient was proposed.The corrected local buckling strength is closer to the finite element result,and the coefficients of variation and dispersion are smaller.