Effect of Initiation Eccentricity on Shaped Charge Jet Forming Process and Power Parameters
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摘要: 为了研究起爆偏心对聚能射流的影响,运用有限元软件LS-DYNA模拟了不同起爆偏心量(0.025Dk~0.125Dk,Dk为装药直径)下射流成型及其破甲过程,探究了药型罩非对称压垮程度、射流形态以及横向速度的变化规律,建立了理论模型以分析不同偏心量下射流横向速度分布情况,并基于正交试验设计理论和方差分析法揭示了各因素对评价指标影响程度的显著差异。结果表明:药型罩非对称压垮程度及射流横向速度均与偏心量呈正相关变化趋势。偏心量为0.025Dk时,射流侵彻深度仅下降0.7%;偏心量为0.050Dk时,侵彻深度下降突跃为12.4%;随着偏心量的增加,侵彻深度继续下降。此外,适当增大壁厚、罩顶装药高度可削弱起爆偏心对射流横向速度的影响。Abstract: In order to study the influence of off-axis initiation on shaped charge jet, the finite element software LS-DYNA was used to simulate the jet forming and armor breaking process under different eccentricities (0.025Dk–0.125Dk, Dk is shaped charge diameter). The asymmetric collapse degree of the liner, jet shape and lateral velocity were investigated. A theoretical model was established to analyze the lateral velocity distribution of jet under different eccentricities. Based on the orthogonal experimental design theory and analysis of variance, the significant difference of the influence degree of each factor on the evaluation index was discussed. The results show that the degree of asymmetric collapse and lateral velocity of jet are positively correlated with the offset. When the offset is 0.025Dk, the percentage of penetration depth was only 0.7%. However, when the eccentricity was 0.050Dk, the percentage of penetration depth suddenly jumped to 12.4%. Moreover, the penetration depth continues to decrease with the increase of offset, seriously affecting the jet’s penetration performance. In addition, the influence of off-axis initiation on jet lateral velocity can be compensated by increasing the thickness of liner and the explosive height above liner.
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Key words:
- shaped charge /
- off-axis initiation /
- tracer method /
- armor-penetrating power /
- orthogonal design /
- variance analysis
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表 1 聚能装药的几何尺寸
Table 1. Structural parameters of shaped charge
Charge diameter Explosive height above liner Cone angle/(°) Thickness of liner Radius of liner curvature Brust height Dk 0.5Dk 60 0.020Dk 0.037 5Dk 3Dk ρ/(g·cm−3) D/(m·s−1) pCJ/GPa A0/GPa B0/GPa R1 R2 1.79 8 730 33.8 795.2 20.2 4.64 1.29 ρ/(g·cm−3) G0/GPa σy/GPa C0/(km·s−1) s1 s2 γ0 8.96 47.7 0.64 3.94 1.49 0 2 表 4 射流成型参数对比(30 μs)
Table 4. Comparison of jet formation parameters (30 μs)
Head jet Tail jet Length Jet deviation vh,sim/(m·s−1) vh,exp/(m·s−1) δ/% vt,sim/(m·s−1) vt,exp/(m·s−1) δ/% Lsim/cm Lexp/cm δ/% ξsim/(°) ξexp/(°) δ/% 6 404 6 600 −2.9 622 745 −16.5 13.45 13.60 −1.1 1.25 1.15 8.6 表 5 正交试验设计
Table 5. Orthogonal test design
Project Factor Evaluation indicator 1 2 3 va/(m·s−1) vb/(m·s−1) L/cm 1 Ⅰ(0.012 5Dk) Ⅰ(0.020Dk) Ⅰ(0.5Dk) 6 384 45.1 8.68 2 Ⅰ(0.012 5Dk) Ⅱ(0.025Dk) Ⅱ(0.8Dk) 6 260 26.2 9.02 3 Ⅰ(0.012 5Dk) Ⅲ(0.030Dk) Ⅲ(1.0Dk) 6 130 17.9 8.93 4 Ⅱ(0.025Dk) Ⅰ(0.020Dk) Ⅱ(0.8Dk) 6 554 78.2 9.18 5 Ⅱ(0.025Dk) Ⅱ(0.025Dk) Ⅲ(1.0Dk) 6 401 57.4 9.02 6 Ⅱ(0.025Dk) Ⅲ(0.03Dk) Ⅰ(0.5Dk) 5 738 75.5 8.76 7 Ⅲ(0.05Dk) Ⅰ(0.020Dk) Ⅲ(1.0Dk) 6 710 154.1 9.11 8 Ⅲ(0.05Dk) Ⅱ(0.025Dk) Ⅰ(0.5Dk) 6 023 187.0 8.54 9 Ⅲ(0.05Dk) Ⅲ(0.030Dk) Ⅱ(0.8Dk) 5 993 135.4 8.94 表 6 计算结果
Table 6. Calculation results
Factor va/(m·s−1) L/cm vb/(m·s−1) Ⅰ Ⅱ Ⅲ Rj Ⅰ Ⅱ Ⅲ Rj Ⅰ Ⅱ Ⅲ Rj K1 18 774 18 693 18 726 26.63 26.96 26.59 89.2 211.1 476.5 K2 19 647 18 684 17 862 26.97 26.58 26.63 277.4 270.6 228.8 K3 18 144 18 807 19 242 25.98 27.14 27.06 307.6 239.8 229.4 k1 6 258 6 231 6 242 27 8.87 8.98 8.85 0.13 29.7 70.4 158.8 129.1 k2 6 549 6 228 5 954 595 8.99 8.86 8.88 0.13 92.5 90.2 76.3 16.2 k3 6 048 6 269 6 414 366 8.66 9.04 9.02 0.38 102.5 79.9 76.5 26.0 -
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