摘要:
格构柱常作为工程结构中主要承重构件,工程服役环境下不可避免地受到其他意外荷载的撞击,建筑结构在冲击载荷下的防护性能评价和优化设计是国防、土木等军民用领域关心的重点问题。本文对格构柱沿不同冲击方向进行了1:2缩比二次冲击实验,每次冲击能量相同,并与相同总能量下的单次冲击格构柱进行了对比,分析了格构柱在冲击荷载下的受力和变形特点。随后,基于实验验证的有限元模型对足尺格构柱进行连续二次冲击模拟,得到了在总能量不变的情况下遭受两次连续冲击的格构柱动力响应结果,分析了不同能量分配对冲击力、残余位移和残余动能的影响。结果表明:在相同总能量下,单次冲击作用下格构柱的位移大于二次冲击,通过数值模拟得到的最优能量分配可以将沿不同方向冲击的构件残余位移减少约12%;当格构柱第一次受到越大比例能量或第二次受到越小比例冲击能时,柱子吸收的总能量越小。研究结果可为此类荷载条件下格构钢柱的设计方法提供参考。
Abstract:
Lattice columns are often used as the main load-bearing components in engineering structures, and are inevitably impacted by other unintentional loads under engineering service environments, and the evaluation of the protective performance and optimization of the design of the building structure under impact loading is a key issue of concern in the fields of national defense, civil engineering, and other military and civilian use. In this paper, 1:2 scaled-down secondary impact experiments were carried out on lattice columns along different impact directions with the same impact energy each time, and compared with single-impact lattice columns under the same total energy, to analyze the force and deformation characteristics of the lattice columns under the impact loads. Subsequently, based on the experimentally verified finite element model, a continuous secondary impact simulation was carried out on the foot-foot lattice column, and the results of the dynamic response of the lattice column subjected to two consecutive impacts with the same total energy were obtained, and the effects of different energy distribution on the impact force, residual displacement and residual kinetic energy were analyzed. The results show that under the same total energy, the displacement of lattice columns under a single impact is larger than that of a secondary impact. The optimal energy distribution obtained by numerical simulation can reduce the residual displacement of members impacted along different directions by about 12%; when the lattice column is subjected to a larger proportion of energy for the first time or a smaller proportion of impact energy for the second time, the total energy absorbed by the column is smaller. The results of the study can provide a reference for the design method of lattice steel columns under such loading conditions.