薄壁角钢轴压稳定承载力试验研究

Experimental study on critical loads of thin-walled angles under axial compression

通过试验、理论、规范和数值分析,研究了薄壁角钢在轴压荷载下的失稳模式和稳定承载力。通过试验得到薄壁角钢试件的稳定承载力,采用有限元软件ANSYS计算一阶屈曲特征值,然后与经典屈曲理论、考虑大变形和非线性项的弹性屈曲理论、国内外规范计算方法所得到的稳定承载力结果对比分析。研究表明:单轴对称的薄壁角钢轴压时发生弯扭屈曲失稳,经典的屈曲理论较为接近试验值及一阶屈曲特征值,可以作为构件稳定承载力的参考,规范得到的稳定承载力考虑了初始缺陷、二阶效应及材料弹塑性的影响,结果偏向保守。

The buckling mode and method to calculate the critical load of the thin-walled angle under axial compression was investigated by analyzing the results of experiments,buckling theory,codes,and the simulation. The critical loads of thin-walled angles were obtained from experiments. The first order eigenvalue of buckling load was analyzed by finite element software ANSYS. The classical linear elastic theory,the elastic buckling theory considering large deformation and nonlinear terms,codes at home and aboard were studied. Results of these methods were compared and analyzed. It's found that the buckling mode is flexural-torsional. The buckling load of the classical linear elastic theory is close to that in the experiments and simulation,which can be the reference of the critical load.Meanwhile,the codes for design of steel structures is conservative as it takes the initial imperfection and plasticity of the material into consideration.