钨铜粉末药型罩形成聚能射流的数值模拟

利用LS-DYNA3D软件对钨铜粉末药型罩聚能射流的形成过程进行了数值模拟,采用多物质ALE算法,模拟了钨铜聚能射流的形成过程,并与实验结果进行了对比。结果表明,随着药型罩密度的增加,射流直径变细,头部速度降低,数值模拟结果与实验结果较一致。     

聚能装药逆向环形起爆射流形成的数值计算

用LS－DYNA程序对小长径比聚能装药逆向环形起爆时形成高速射流以及正向起爆时形成低速射流进行了三维数值模拟,计算结果与实验吻合,计算的逆向起爆形成射流头部速度为8．78km/s,而正向起爆形成的射流头部速度为4．86km/s。数值模拟证明：长径比聚能装药逆向环形起爆时形成高速金属射流是可行的。     

水下线形聚能装药切割钢靶的数值模拟及试验验证

应用ANSYS/LS-DYNA软件对不同结构线形聚能装药所形成的聚能侵彻体及切割钢靶过程进行了数值模拟。基于数值模拟设计了不同结构的线形聚能切割器,进行了切割器切割钢靶的验证试验。结果表明,在水介质中,随炸高的增加侵彻体头部速度衰减加快,切割能力下降;侵彻体切割深度沿装药长度方向呈增长趋势,随装药长度的增加将逐步达到稳定状态。     

线性聚能装药切割岩石的数值模拟

运用改进的MOCL程序,数值模拟了线性聚能装药金属射流的形成以及射流侵彻岩石的全过程,得到了锥角为60°的聚能装药结构爆轰产物膨胀、药型罩变形、射流形成过程及锥角为60°和90°时的射流速度梯变分布。不同时刻射流的分布显示,在拉伸过程中,锥角为60°的聚能射流速度变小,速度梯度较大,头部速度为4500m·s-1;锥角为90°的聚能射流,头部速度为3500m·s-1速度梯度较小,与实际物理过程相一致。结果表明,模拟结果基本符合聚能射流的物理现象和规律,说明采用的物理模型和数值算法是合理的。     

混凝土环境对典型聚能射流成型影响的数值模拟

结合前级聚能装药形成的混凝土环境的特点,利用有限元模拟软件AUTODYN对3种典型聚能装药在混凝土环境中的射流成型情况进行了数值模拟,对在空气和2mm铝壳体环境中的数值计算结果进行了比较,并通过实验对数值计算结果进行了验证,实验结果与计算值吻合较好.结果表明,混凝土环境对亚半球装药影响最大,较大地提高了头部速度;对K装...     

装药长径比对半球形聚能装药射流成型的数值模拟

为了得到均匀、不易中断的射流,运用ANSYS/LS-DYNA软件的二维多物质纯ALE算法,建立不同装药长径比有限元模型,数值模拟了6种不同长径比的半球形聚能装药产生射流的过程,对比分析了同一时刻、同一时间段6种装药长径比对射流成型的影响。结果表明,70.5μs时,装药长径比从0.8增至1.8,射流头部速度增大31.9%,射流长度减小23.2%;46.5~70.5μs时段,射流长径比与时间呈类线性增长,射流在装药长径比约为1.2时不易断裂,均匀性最好。     

起爆方式对线性聚能装药射流形成的影响

以工程中常用的柔性切割器为研究对象,在不考虑端部效应的前提下,对3种起爆方式下线性聚能装药射流的形成过程进行了理论分析和数值模拟。结果表明,不同起爆方式下射流头部速度以端部面起爆最大,线起爆次之,端部点起爆在端面附近处形成的最低,但在距端面一定距离处,射流头部速度又能增大到与端部面起爆的速度相近。在射流内部,端部面起爆形成的射流在内部各点处的速度都是3种起爆方式中最大的,而端部点起爆时,则是随着距起爆点距离的增加由处处小于线起爆的射流速度分布转变到与端部面起爆相同的射流速度分布。在此基础上进一步提出3种起爆方式下线性聚能装药切割目标的数值模拟方法。     

变壁厚石油射孔弹聚能射流形成的影响因素分析

为研究药型罩锥角、壁厚等对石油射孔弹聚能装药引爆形成的聚能射流影响,利用有限元分析软件ANSYS/LS-DYNA,采用ALE方法对变壁厚石油射孔弹聚能射流的形成过程进行了模拟分析,得出型罩结构与射流头部速度的关系。研究结果表明,药型罩锥角越大,射流速度越小,形成的杵体长度相比于射流的长度也越小;同锥角药型罩壁厚越小,聚能射流的形态发育得越好,药型罩壁厚越大,射流速度越低。     

辅助药型罩材料对超聚能射流性能影响的数值模拟

为了研究超聚能射流形成过程中辅助药型罩材料对射流性能的影响,利用AUTODYN-2D软件,采用高精度多物质求解器Euler-2D Multi-material对辅助药型罩材料分别为Wu、Cu、Fe,锥形药型罩材料为Al的截顶辅助药型罩超聚能装药进行模拟。结果表明,与传统聚能装药相比,超聚能装药结构形成的射流性能更优。辅助药型罩材料密度越大,超聚能射流形态和连续性越好;超聚能射流具有更高的头部速度和能量。用Wu、Cu、Fe作辅助药型罩材料时,超聚能射流的最大速度分别为14 400、13 300和13 100m/s,最大能量分别为10.2×10~7、8.5×10~7、7.5×10~7 J/kg,并且材料密度越大,起爆后相同时刻的射流形态越细越长。     

线性聚能装药对自锻弹丸干扰的数值模拟

为了研究线性聚能装药以不同角度干扰自锻弹丸的效果,采用有限元软件ANSYS/ls-dyna对线性聚能装药从不同角度(0°、30°、60°、90°)干扰自锻弹丸以及自锻弹丸被干扰后侵彻45号钢板的全过程进行数值模拟,然后运用Lsprepost后处理软件分析了自锻弹丸与聚能装药的射流头部在相遇前、相遇过程以及相遇后侵彻45号钢板过程中3个阶段的物理变化,通过分析对比自锻弹丸被干扰后的偏转距离、破碎程度、侵彻能力等确定了线性聚能装药干扰自锻弹丸的最佳干扰角度。结果表明,线性聚能装药可以对自锻弹丸进行有效的干扰,其干扰角度对干扰效果有较大影响。在0°~90°范围内,干扰角度为60°时干扰效果最佳。     

药型罩切分方式对射流形成影响的数值模拟

为了研究药型罩切分方式对其形成射流性能的影响,利用数值模拟软件ANSYS/LS-DYNA对横向切分和纵向切分的药型罩以及未切分药型罩在爆轰波作用下形成射流的过程以及对45号板的侵彻能力进行了数值模拟,比较了不同切分方式的药型罩在爆轰波作用下形成射流的形状、头尾部速度、拉伸长度和抗拉伸性能及其对45号钢板的侵彻能力。结果表明,在相同装药条件下,横向切分药型罩相比纵向切分药型罩的头部速度提高约220m/s,且抗拉伸性能更好,对45号钢板的侵彻深度提高约3.26cm;横向切分药型罩相比未切分药型罩的头部速度提高约360m/s,对45号钢板的侵彻能力提高约5.62cm。     

环形EFP成型及侵彻过程的数值模拟

在分析环形射流形成机理的基础上,利用LS-DYNA软件对环形EFP的成型与侵彻过程进行了数值模拟.通过对环形药型罩及其聚能装药结构参数的合理匹配,解决了环形药型罩成型翻转过程中的偏斜飞散问题,探索了实用环形EFP工程设计的技术途径.计算结果表明,在0.26倍装药长径比和4倍装药口径的炸高条件下,环形EFP对45号钢的侵彻孔径可达到0.96倍装药口径.     

某成型装药射流的数值模拟与射流转化率

应用LS-DYNA及示踪点处理技术,对某一球锥罩成型装药结构的射流形成过程及射流侵彻靶板过程进行了研究,获得了有效射流沿其运动方向的速度分布、头部速度、侵彻孔几何描述等多项评估射流微元性能的重要参数。计算结果表明,对于普通强度钢质目标靶,在射流侵彻靶板过程中,常规小锥角药型罩产生的有效射流为2000m/s以上的射流段,杆式射流的临界侵彻速度值为1400m/s,从而进一步得到其射流转化率为29.65%。     

Methodology for simulation of the jet formation process in an elongated shaped charge

The performance of linear shaped charges depends on several different parameters. The density, the detonation velocity of the explosive, the shape of the detonation wave, the shape and wall thickness of the liner, and the distance of the shaped charge from the target are among the parameters that can be optimized by using computer simulation methods. In this paper, the jet formation process in a linear shaped charge and its action on an obstacle are simulated by using the LS-DYNA software. The results obtained are compared with experimental data.     

Numerical simulation of the formation of shaped-charge jets from hemispherical liners of degressive thickness

The formation of shaped-charge jets from hemispherical copper liners of degressive thickness (decreasing from apex to bottom) is analyzed by numerical simulation of a twodimensional axisymmetric problem of continuum mechanics. The comparison was based on the parameters of the jet formed from a modern standard shaped charge with a conical liner which provides penetration of a steel target to a depth equal to 10 charge diameters. The comparative analysis was performed using calculated mass–velocity distributions and the ultimate jet length–velocity distributions obtained on their basis, from which the potential penetrability of jets was evaluated. It is shown that the shaped-charge jets formed by hemispherical shaped-charge liners of degressive thickness are comparable in head velocity and penetrability to the jets from conical liners.     

Shaped charge jet interaction with Highly Effective Passive Sandwich Systems - experiments and analysis

The development and investigation of reactive sandwich targets and their interaction with shaped charge jets is one of the many research areas, where important contributions were made by Manfred Held. Such reactive sandwiches are known to be extremely effective against jets, but have a number of disadvantages. In this work, the interaction of the copper jet from a shaped charge calibre 136 mm with a double sandwich system, each sandwich consisting of a non-reacting layer between outer steel plates, is investigated. In 10 experiments with identical geometrical setup, only the material of the non-reacting layer is changed. Using flash X-ray pictures, the interaction of the jet with the sandwich system is investigated. Evaluation of these pictures as well as the comparison of the measured residual penetrations behind the sandwich target clearly demonstrate the influence of the material of the inner sandwich layer. The deformation and movement of the steel plates, caused by the penetrating jet, can be seen in the X-ray pictures. It is shown that it is possible to distort a shaped charge jet so that its penetration capability behind the target is reduced to a minimum. A fully three-dimensional hydrocode simulation of the experiments enabled the jet/sandwich interaction and steel plate deformation and rupture to be studied in detail.