压实系数对内填砂卵石薄壁方钢管柱在冲击载荷下力学性能的影响分析

利用落锤冲击装置完成了不同压实系数下内填砂卵石薄壁方钢管柱侧向冲击试验,试验中记录了冲击力时程曲线,并获得了试件的破坏形态以及残余变形量。基于剩余承载力损伤评估准则,定义损伤度来判定冲击荷载下内填砂卵石薄壁方钢管柱损伤破坏程度,分析压实系数与柱损伤度的关系。试验结果表明:试件在侧向冲击荷载作用下,主要以局部破坏为主,并伴有一定量的整体弯曲变形;除了试件塑性变形中产生的塑性铰能消耗部分冲击能量外,内填砂卵石也能耗散一部分冲击能量,且压实越紧密,能量消耗越多,该组合柱表现出了较好的抗冲击性能;在一定压实系数范围内,损伤度随着压实系数增大出现先增大后减小的趋势,且砂卵石离散程度越小,损伤度的变化速率就越大。

Effect of compaction factor on the mechanical property of square thin-walled steel tube columns filled with sandy pebble under impact load

Square thin-walled steel tube columns filled with sandy pebble were tested under different compaction factors and lateral impacts by a drop-hammer-tester. In the experiment,time-history curves were recorded,together with the damage form and residual deformation of specimens. Based on the damage assessment criteria of residual capacity,the index of damage degree was introduced and defined to evaluate the damage of square thin-walled steel tube columns under different impact loads. Moreover,the relationship between the compacting factor and damage degree was analyzed. The results show that the damage of specimens is mainly owing to the local failure with a certain amount of overall bending under lateral impact. The impact energy is dissipated not only by the plastic hinge energy consumption due to plastic deformation,but also the filled sandy pebble,and the more tightly compacted,the more energy consumed. Thus,the columns filled with sandy pebble show a favorable anti-collision performance. Within a certain range of compaction factor,the damage degree first increases then decreases with the increase of compaction factor,and its changing rate is greater when the discrete degree of sandy pebble is smaller.