主体结构荷载可控的新型组合式防护结构(Ⅰ):抗爆机制

A new composite protective structure based on the controllability of blast load on the structure layer(Ⅰ):blast resistance mechanism

针对以中粗砂为分配层的传统成层式结构难以可靠控制作用于主体结构上荷载的缺陷,以及以泡沫混凝土为夹层的组合式防护结构抗爆机制不明等问题,开展组合式防护结构预制孔装药爆炸试验,测得特定位置处的爆炸波时程曲线和结构损伤破坏情况。并基于Kong-Fang混凝土材料模型和LS-DYNA中的光滑粒子伽辽金(smoothed particle Galerkin,SPG)算法,开展了爆炸波在组合式防护结构中传播衰减规律和损伤破坏的数值模拟研究。试验和数值模拟结果表明:组合式防护结构的抗爆机制在于遮弹层和泡沫混凝土层之间的强波阻抗失配关系,通过调控爆炸能量的分配,使得爆炸能量大部分耗散在遮弹层中,大幅减少了经泡沫混凝土层到达主体结构上的荷载和能量。

The layered protective structure composed of a bursting layer,distribution layer,and structure layer is usually used to resist the penetration and blast waves induced by advanced earth-penetrating weapons(EPWs).The defect of a traditional layered protective structure with medium/coarse sand as the distribution layer is that it is difficult to reliably control the load on the structure layer.To solve this issue,an alternative approach is presented by replacing the material of the distribution layer from the frequently used medium/coarse sand to foam concrete.A blast test on the layered composite target composed of a CF120 concrete(a fiber-reinforced high-strength concrete)bursting layer,a C5 foam concrete distribution layer,and a C40 reinforced concrete structure layer was first conducted in the present study to investigate the blast resistance of layered protective structure sandwiched by foam concrete(named composite protective structure),in which the damage and failure in the layered composite target and blast waves at specific locations were a major concern and were accurately recorded.Then,based on the concrete material model established by Kong and Fang and the smoothed particle Galerkin(SPG)algorithm available in the LS-DYNA,a corresponding numerical model was developed and validated against the test data.Using the validated numerical model,the propagation and attenuation of blast waves and damage and failure in the composite protective structure induced by cylindrical charge explosion are discussed in detail.It is found that the blast resistance mechanism of the composite protective structure is attributed to the extreme wave impedance mismatch between the bursting layer and the foam concrete layer,which greatly reduces the propagation of blast waves into the foam concrete layer,leading to a transformation of more blast energy to the bursting layer,so that the blast load and energy on the structure layer can be greatly reduced.The research results can provide an important reference for the design of protective structures against EPWs.