冲击作用下框架结构的连续性倒塌性能

借助ANSYS/LS-DYNA软件建立了钢筋混凝土框架的有限元模型,研究了钢筋混凝土框架在冲击荷载作用下的连续性倒塌性能,冲击体质量为1000 kg,冲击速度为4 m/s。通过对钢筋混凝土构件冲击试验和框架倒塌过程的验证,保证了数值模拟的有效性。分析结果表明:冲击中柱后结构倒塌过程中,有"拱作用"向"悬索作用"转换的机制,中柱顶部位移先向上后向下,边柱顶部位移先向外后向内;同样冲击作用下,柱轴力越小,则抗冲击能力越强,不同的偏压作用对柱的抗冲击性能的影响不同;加密柱箍筋能够增强钢筋混凝土柱的抗冲击能力,延缓甚至避免钢筋混凝土框架结构的连续性倒塌。

Continuous Collapse Behavior of Frame Structures under Impact

In order to study the continuous collapse behavior of reinforced concrete frame under impact load,the finite element model of reinforced concrete frame is established by ANSYS/LS-DYNA.The impact mass is 1000 kg and the impact velocity is 4 m/s.The effectiveness of the numerical simulation is guaranteed by the verification of the of reinforced concrete members impact experiment and the frame collapse process.The analysis draws following conclusions:in the process of structure collapse of the mid column impacted,there is a mechanism of"arch effect"to"suspension effect",the top of the middle column first goes up and then down,and the top of the side column first goes out and then inward;under the same impact load,the smaller the column axial force,the stronger column impact resistance and the column impact resistance is affected by different eccentric pressure.The impact resistance of reinforced concrete columns can be enhanced by infill column stirrups which can delay or even avoid the reinforced concrete frame structures continuous collapse.