为研究爆炸作用后二次起爆对单箱三室混凝土箱梁的破坏行为,开展节段箱梁试件箱外/箱内连续爆炸试验。在10 kg TNT药柱爆炸作用后,施加5 kg TNT药柱继续作用,观测箱梁试件毁伤及动态响应。利用LS-DYNA软件分析了TNT当量、爆炸距离及起...为研究爆炸作用后二次起爆对单箱三室混凝土箱梁的破坏行为,开展节段箱梁试件箱外/箱内连续爆炸试验。在10 kg TNT药柱爆炸作用后,施加5 kg TNT药柱继续作用,观测箱梁试件毁伤及动态响应。利用LS-DYNA软件分析了TNT当量、爆炸距离及起爆位置对箱梁破坏形态及动态响应的影响。结果表明:5 kg TNT炸药在中间箱室底板中心正上方0.35 m处二次起爆后,中间箱室顶板破洞进一步增大,底板破洞沿横、纵桥向长度分别为48.50 cm、62.50 cm,底板中心钢筋凹陷18.30 cm,两侧腹板有明显损伤。采用10 kg、5 kg TNT分别对3个箱室进行箱外/箱内连续爆炸作用,且二次起爆为内部接触爆时,箱室顶、底板均出现贯穿性破洞,底板破洞均大于顶板。相较于药柱位于箱室底板上方0.35 m,采用接触起爆时,箱室顶板沿横、纵桥向破洞长度分别减小21.2%、33.8%,底板破洞长度分别增加103.9%、113.2%。展开更多
为了分析水下连续爆炸的水声学特性,采用具有统一时间间隔的多个爆炸单元进行水下连续爆炸试验及测量。根据测试获得的声信号数据,分析了水下连续爆炸冲击波的衰减及传播特性,研究了声信号的声持续时间、声压级和声能量。研究表明,水下...为了分析水下连续爆炸的水声学特性,采用具有统一时间间隔的多个爆炸单元进行水下连续爆炸试验及测量。根据测试获得的声信号数据,分析了水下连续爆炸冲击波的衰减及传播特性,研究了声信号的声持续时间、声压级和声能量。研究表明,水下连续爆炸会产生很强的声功率,声持续时间为连续爆炸单元的爆炸时间间隔之和。声信号的频率范围宽,其能量主要集中分布在频率24 k Hz以下,在低频段能量更大。说明水下连续爆炸作为功率高、频带宽、声持续时间长的水声声源,在水声干扰方面具有重要作用。展开更多
The spallation of the concrete slabs or walls resulting from contact detonation constitutes risk to the personnel and equipment inside the structures because of the high speed concrete fragments even though the overal...The spallation of the concrete slabs or walls resulting from contact detonation constitutes risk to the personnel and equipment inside the structures because of the high speed concrete fragments even though the overall structures or structural members are not destroyed completely. Correctly predicting the damage caused by any potential contact detonation can lead to better fortification design to withstand the blast Ioadings. It is therefore of great significance to study the mechanism involved in the spallation of concrete slabs and walls. Existing studies on this topic often employ simplified material models and 1D wave analysis, which cannot reproduce the realistic response in the spallation process. Numerical simulations are therefore carried out under different contact blast Ioadings in the free air using LS-DYNA. Sophisticated concrete and reinforcing bar material models are adopted, taking into account the strain rate effect on both tension and compression. The erosion technique is used to model the fracture and failure of materials under tensile stress. Full processes of the deformation and dynamic damage of reinforced concrete （RC） slabs and plain concrete slabs are thus observed realistically. It is noted that with the increase of quantity of explosive, the dimensions of damage crater increase and the slabs experience four different damage patterns, namely explosive crater, spalling, perforation, and punching. Comparison between the simulation results of plain concrete slabs and those of RC slabs show that reinforcing bars can enhance the integrity and shearing resistance of the slabs to a certain extent, and meanwhile attenuate the ejection velocity and decrease the size of the concrete fragments. Therefore, optimizing reinforcement arrangement can improve the anti-spallation capability of the slabs and walls to a certain extent.展开更多
文摘为研究爆炸作用后二次起爆对单箱三室混凝土箱梁的破坏行为,开展节段箱梁试件箱外/箱内连续爆炸试验。在10 kg TNT药柱爆炸作用后,施加5 kg TNT药柱继续作用,观测箱梁试件毁伤及动态响应。利用LS-DYNA软件分析了TNT当量、爆炸距离及起爆位置对箱梁破坏形态及动态响应的影响。结果表明:5 kg TNT炸药在中间箱室底板中心正上方0.35 m处二次起爆后,中间箱室顶板破洞进一步增大,底板破洞沿横、纵桥向长度分别为48.50 cm、62.50 cm,底板中心钢筋凹陷18.30 cm,两侧腹板有明显损伤。采用10 kg、5 kg TNT分别对3个箱室进行箱外/箱内连续爆炸作用,且二次起爆为内部接触爆时,箱室顶、底板均出现贯穿性破洞,底板破洞均大于顶板。相较于药柱位于箱室底板上方0.35 m,采用接触起爆时,箱室顶板沿横、纵桥向破洞长度分别减小21.2%、33.8%,底板破洞长度分别增加103.9%、113.2%。
文摘为了分析水下连续爆炸的水声学特性,采用具有统一时间间隔的多个爆炸单元进行水下连续爆炸试验及测量。根据测试获得的声信号数据,分析了水下连续爆炸冲击波的衰减及传播特性,研究了声信号的声持续时间、声压级和声能量。研究表明,水下连续爆炸会产生很强的声功率,声持续时间为连续爆炸单元的爆炸时间间隔之和。声信号的频率范围宽,其能量主要集中分布在频率24 k Hz以下,在低频段能量更大。说明水下连续爆炸作为功率高、频带宽、声持续时间长的水声声源,在水声干扰方面具有重要作用。
基金Supported by the National Defense Preliminary Research Project Fund of Zhejiang University,and Qianjiang Talent Plan.
文摘The spallation of the concrete slabs or walls resulting from contact detonation constitutes risk to the personnel and equipment inside the structures because of the high speed concrete fragments even though the overall structures or structural members are not destroyed completely. Correctly predicting the damage caused by any potential contact detonation can lead to better fortification design to withstand the blast Ioadings. It is therefore of great significance to study the mechanism involved in the spallation of concrete slabs and walls. Existing studies on this topic often employ simplified material models and 1D wave analysis, which cannot reproduce the realistic response in the spallation process. Numerical simulations are therefore carried out under different contact blast Ioadings in the free air using LS-DYNA. Sophisticated concrete and reinforcing bar material models are adopted, taking into account the strain rate effect on both tension and compression. The erosion technique is used to model the fracture and failure of materials under tensile stress. Full processes of the deformation and dynamic damage of reinforced concrete （RC） slabs and plain concrete slabs are thus observed realistically. It is noted that with the increase of quantity of explosive, the dimensions of damage crater increase and the slabs experience four different damage patterns, namely explosive crater, spalling, perforation, and punching. Comparison between the simulation results of plain concrete slabs and those of RC slabs show that reinforcing bars can enhance the integrity and shearing resistance of the slabs to a certain extent, and meanwhile attenuate the ejection velocity and decrease the size of the concrete fragments. Therefore, optimizing reinforcement arrangement can improve the anti-spallation capability of the slabs and walls to a certain extent.
