冲击波加载区域对冲击波速度和衰减的影响  

Influence of shockwave loading area on its propagating velocity and decay law

作　　者：张世文[1] 胡美娥[1] 贾宏志[1] 

机构地区：[1]中国工程物理研究院流体物理研究所,绵阳621999

出　　处：《应用力学学报》2016年第3期371-377,541,共7页Chinese Journal of Applied Mechanics

摘　　要：以工程采用的冲击波衰减电探针测试方法为基础,通过数值模拟研究了冲击波加载区域对冲击波传播速度和冲击波衰减测量结果的影响。结果表明:对非一维平面正冲击波,冲击波的径向几何弥散对冲击波传播速度影响显著;针对本文算例,当电探针离自由面0.05mm时,冲击加载半径R=10mm、R=20mm比R=80mm所测电探针导通时间分别长7.79μs、1.28μs,一维平面波理论高估了实际测试的冲击波传播速度,冲击加载面积越小,冲击波衰减越快;在同一时刻(30μs)和同一位置(L=80mm),加载半径R=80mm的冲击压力是R=20mm的5倍还多,一维平面波理论低估了冲击波衰减程度,点撞击引起的散心冲击波则相反。因此目前获得的各种冲击波衰减经验公式应强调其加载条件和适用范围,特别是散心冲击波实验获得的冲击衰减拟合公式有可能降低设计安全阈值。Based on the test methods of electrical pins used in engineering experiment on shockwave decay, the influence of shockwave loading area on the measurement results about shockwave velocity and decay law through numerical simulation is studied. It is found that one-dimensional plane wave theory overestimates shockwave propagating velocity in the realistic tests. In our simulations, the time while the shock wave reaches electrical probes located 0.05 mm from the free surface is 7.79 s and 1.28 s later when the radius of the loading area is 10 mm and 20 mm, respectively, than that when the radius of the loading area is 80 mm, which means overestimation of shock wave propagating velocity by one-dimensional plane wave theory. Moreover, at the same time(30s) and location(L=80mm), the shock pressure of R=80mm loading is larger than 5 times that of R=20mm loading, which is opposite to the case in divergent detonation loading and indicates that one-dimensional plane wave theory also underestimates the extent of its decay, which stems from its dispersive effect of radial geometry. However, the inverse trend is for the divergent shockwave caused by point impact, is just opposite. Therefore, for the gained phenomenological formula about shockwave decay at present, its loading condition and application scope are accounted for, in particular in the latter case where via the formula the threshold of safety design may become lower.

关 键 词：冲击动力学 冲击波压力 衰减规律 几何弥散 数值模拟 

分 类 号：O382[理学—流体力学]