内部爆炸荷载作用下钢筋混凝土板碎片抛射速度的预测

PREDICTION OF DEBRIS LAUNCH VELOCITY OF REINFORCED CONCRETE SLAB SUBJECTED TO INTERNAL BLAST LOADING

大型地上军火库由于发生偶然的爆炸,相应的钢筋混凝土结构在内部爆炸荷载作用下的动力响应特别是碎片的大小和抛射速度将会对周围的人造成巨大的伤害。因此,合理地预测钢筋混凝土结构的损伤破坏及碎片形成和抛射速度已成为军火库安全性能评估的重要关注问题。该文对箱型封闭空间内钢筋混凝土板在内部爆炸荷载作用下的动力响应进行了数值模拟研究,模型考虑了应变率对钢筋和混凝土材料动力本构特性的影响以及空气-结构之间的流固耦合相互作用,数值分析结果展示了钢筋混凝土板在内部爆炸冲击波和气体压力荷载作用下从损伤破坏、碎片形成到抛射的动态演变过程,混凝土碎片大小和抛射速度与试验结果吻合较好。研究结果表明:爆炸冲击波影响钢筋混凝土板的开裂破坏和碎片的大小,而气体压力荷载对碎片的形成和抛射速度起着重要的作用。

Due to the accidental explosion of a large-scale aboveground ammunition storage magazine, the dynamic response under internal blast loading, especially the size and launch velocity of debris of reinforced concrete structures, can cause huge damage to surrounding persons and buildings. Therefore, predicting accurately the debris formation and launch velocity of RC structures has become an important issue for the safety assessment of ammunition storage magazine. In this paper, a numerical model of RC slab bolted to the cubic steel box at the four ends is established with the explosive charge placed at the centre of the chamber. The numerical model adopts a three-curve concrete strength model to reinforcement dynamic strength. The air-structure account for the effect of strain rate on the concrete and coupled interaction is also considered. With the numerical model, the whole evolving process is simulated including break-up, debris formation and launching of RC slab. The simulation results are compared with experimental results, and good agreements are observed in the launch velocity and sizes of debris. It is also found that the shock wave load is responsible for the development of damage zone in the concrete material and the subsequent debris size distribution, and the gas pressure load plays an important role in the separation of crack pattern and in the subsequent throw of the debris.