爆炸加载下金属柱壳破片软回收技术研究

针对爆炸加载下金属柱壳膨胀断裂破片软回收的研究需求，本文通过理论分析和初步的数值模拟设计了由低密度聚氨酯泡沫与水介质为主体的回收装置。与传统单一材料为主的回收装置相比，该回收装置既能在破片高速阶段将低阻抗聚氨酯泡沫对破片的冲击压力减小到约为水对破片冲击压力的1/3，又使破片速度全程持续地较大幅度衰减，还能在破片低速阶段又能充分利用水介质密度大的优势，减小以聚氨酯泡沫单一材料为主的回收装置尺寸。依托该装置开展了炸药加载下304不锈钢柱壳膨胀断裂回收实验。通过测量回收池外壁速度、检查实验后的回收池外观，发现回收池池壁和底部完好，可以重复使用；通过对回收破片称重统计，破片回收率超过85%，破片内外界面辨识度高，破片表面车刀纹清晰可见，内部可见多条未贯穿的裂纹。表明该回收装置对破片的冲击损伤显著降低。根据破片断口和表面信息，推测了破片在金属柱壳的大致位置。本文最后初步给出了回收破片的平均厚度及质量分布等相关信息的统计结果。

Investigation on the technology of soft recovery of fragment produced by metal cylindrical shell subjected to explosive loading

According to the requirements on the soft recovery of fragments of expanding cylindrical metal shells under explosion loading, this paper presents a recovery device combining low density polyurethane foam and water medium through theoretical analysis and numerical simulation. Compared to traditional recovery device designed with a single material, the combined recovery device can reduce the amplitude of impact pressure, which is produced by the initial interaction of low impedance polyurethane foam with high speed fragments, by about 1/3 compared to the impact pressure produced by water, and maintain the high decay rate of fragment speed. It can also make full use of the advantages of high density of water medium when the fragment speed is less than 0.5 km/s, which can reduce the decay thickness of the recovery device based on single polyurethane foam. Based on the device, the recovery experiment of expansion and fracture of 304 stainless steel cylindrical shell under explosive loading is carried out. Through the measurement of the wall velocity of the recovery tank and the appearance inspection after the experiment, it is implied that the wall and bottom of the recovery tank are in good condition and can be reused. According to the statistics of the recovered fragments, the recovery rate of the fragments is more than 85%, and the internal and external interfaces of fragments are highly recognizable, the turning blade lines on the surface of the fragments are clearly visible, and several non-penetrating cracks are visible, which verified that the impact damage of the recovery device to the fragments is significantly reduced. Acording to the fracture and surface information of the fragments, the approximate position of the fragments in the metal cylindrical shell is inferred. Finally, the statistical results of the average thickness and mass distribution of the recovered fragments are given.