不同柱端约束下外方内圆双重钢管混凝土组合柱抗侧向冲击动力性能研究

Study on dynamic behavior of hollow concrete filled steel tubular columns with different end constraints under lateral impact

为研究不同柱端约束作用下方形空心钢管混凝土柱受冲击后的动力性能,对已有试验的钢管混凝土柱进行模拟,验证了有限元模拟分析的可靠性。基于有限元模拟,完成了16个钢管混凝土柱的水平横向冲击数值模拟,分析不同柱端约束条件和柱端轴力大小对钢管混凝土侧向冲击动力性能的影响。结果表明:方形空心钢管混凝土柱受到冲击作用后,冲击侧发生局部鼓曲,冲击部位主要表现为剪切变形,而另一侧主要表现为弯曲变形;柱端未施加轴力条件下,加强柱端约束均有利于提高柱抗侧向冲击动力性能,减少冲击部位和柱整体的变形;柱端约束相同的条件下,柱端施加轴力会对试件抗侧向冲击性能产生不利作用;在固端约束条件下,轴力为柱轴压承载力0.01倍时,冲击力峰值达到最小值,随后冲击力峰值得到一定程度的回升,此时轴压力对空心钢管柱起到一定的保护作用;施加轴力后的悬臂柱由于悬臂端受到轴压力的限制,间接增大了悬臂柱的约束,导致试件柱比预计吸收更多能量。

In order to study the dynamic performance of square hollow concrete filled steel tubular columns under different end restraints,the concrete-filled steel tubular columns of existing test are simulated,and the reliability of finite element simulation analysis is verified.Based on the finite element simulation,the 16 concrete filled steel tubular columns under impact is simulated,with the effects investigated of confinement conditions at the end of the column and the magnitude of the axial force applied at the end of the column on the lateral impact dynamic properties of concrete filled steel tubular(CFST).The results show that local buckling occurs on the impact side of square hollow concrete filled steel tubular columns under impact,and that the main impact part is shear deformation,while the other side is bending deformation.When the axial force applied at the end of the column is zero,strengthening the restraint at the end of the column can improve the dynamic performance of the column against lateral impact and reduce the deformation of the impact part and the whole column.Compared with the case without axial force,the axial force at the end of the column will have an adverse effect on the lateral impact resistance of the specimen.Under the fixed-end constraint condition,when the axial force is in the range of the test parameters,the peak value of impact force reaches the minimum value for the axial force to be 0.01 F,with the peak value of impact force rising to a certain extent.At this time,the axial pressure plays a certain protective role in hollow steel tube columns.The restraint of the cantilever column increases indirectly due to the restriction of the axial pressure on the cantilever end,resulting in the increase of the restraint of the cantilever column and the specimen column absorbing more energy than expected.