近爆作用下钢筋混凝土π梁防护性能的数值模拟

Numerical simulation for protective of reinforced concrete π beams under close-in explosion

为研究钢筋混凝土π截面梁在近场爆炸荷载作用下的防护方法,采用ANSYS/LS-DYNA建立π梁爆炸数值模型,结合现场爆炸试验结果,对π梁在爆炸荷载作用下的破坏形态进行对比分析,验证数值模型的准确性。通过π梁在近爆荷载下采用不同防护层进行模拟分析,对π梁在不同防护工况下冲击波超压峰值分布规律、结构耗能规律、防护后π梁的破坏形态进行研究。研究发现,在钢板和泡沫铝组合防护层作用下,π梁冲击波超压峰值相对较小。而且随着纵向距离的增大,冲击超压在顶板迎爆面衰减幅度最大。钢板和泡沫铝组合防护层耗能能力较强,所消耗的能量占π梁三部分(混凝土、钢筋、防护层)总能量的90%。近爆作用下,各防护工况π梁的破坏模式均为局部破坏,无整体变形,翼缘板、腹板未发生破坏。其中,π梁在钢板和泡沫铝组合防护下损伤区域相对较小,防护能力相对较好。

In order to investigate the protection method of reinforced concrete π-beam under near-field explosion load, ANSYS/LS-DYNA was used to establish the beam explosion numerical model. According to the results of field explosion test, the failure modes of the beam under explosion load were compared, and the accuracy of numerical model was verified. Based on the numerical analysis of different protection forms of π-beams under explosive loads, the peak distribution of shock wave overpressure was studied under different protection conditions. The law of structural energy consumption, the damage pattern of the π beam after protection, and the protection efficiency of different protective layers were also investigated. The testing results indicate that the peak value of shock wave overpressure is relatively small under the combined protection of a steel plate and an aluminum foam. Besides, as the longitudinal distance increases, the impact overpressure attenuates most heavily on the roof’s explosion-facing surface. Meanwhile, the combined protective of the steel plate and the aluminum foam layer has a strong energy consumption capacity, the energy consumed by accounts for 90% of the three parts of the π beam(concrete, steel, and protective layer). The failure mode of π-beams under various protective conditions is a partial failure, without overall deformation or damage to the flange plate and web. The damaged area of π-beam is relatively small under the combined protection of steel plate and aluminum foam, and the combined protection layer is relatively good.