基于LS-PrePost的不同形状装药爆炸仿真研究

LS-PrePost-based Simulative Explosion with Shape-different Charging

LS-PrePost是一款功能强大、操作便捷的爆炸仿真软件。*INITIAL_VOLUME_FRACTION_GEOMETRY和*LOAD_BLAST是LS-PrePost中的关键字卡片,而SPH是一种光滑粒子流体动力学方法,都可以用来施加爆炸载荷。为研究球形装药爆炸仿真建模方法,使用以上方法进行建模,分析不同建模方法的优缺点及适用场景。选择最优建模方法研究1 kg TNT炸药不同形状装药爆炸产生空气冲击波的不同。本文在研究爆炸仿真建模现状的基础上,查阅文献资料,选择最优建模方法。在经过验证的有限元模型上进行爆炸仿真,模拟实验仅改变装药形状参数,对球形、柱形、方形装药的有限元爆炸模型进行求解,得到不同比例距离下的超压峰值,制作图表比较各组超压峰值数据的差异。结果表明,在比例距离小于等于1.0 m·kg^(-1/3)时,柱形装药的超压峰值与球形装药更接近,而方形装药超压峰值与球形装药差异更大;随着比例距离的增加,柱形装药的峰值超压与球形装药的比值变化不大,而方形装药的峰值超压与球形装药的比值逐渐增加,变化较大。不同装药形状对于爆炸产生的冲击波超压的影响是不容忽视的,在研究实际爆炸案件的装药及其爆炸破坏作用时,应尽可能采用最接近实际情况的装药形状。在通过爆炸仿真方法研究问题时,也要选择合适的建模方法和装药条件,才能保证分析结果的准确可靠。

Simulative explosion is usable for restoring the course of involving event and reconstructing the relevant case scene.Hence,three choices of LS-PrePost-based simulative modeling were here tried about explosion with spherical charging:the keyword*LOAD_BLAST-guided,the SPH-directed and the keyword*INITIAL_VOLUME_FRACTION_GEOMETRYled,thus having their advantages and disadvantages analyzed along with the applicable scenarios.All the simulations were conducted under the optimal load of 1 kg TNT charged into three different shapes so that the generated blast air-shock waves(represented with peak overpressure)were able to unfold their variations.The fi nite element software LS-PrePost was utilized to put into a verifi ed fi nite-element model for the explosion simulation to carry out,with every simulation only changing the shape parameter of charging.The ANSYSLS-DYNA was the solver to respond the discrepant ways of spherical,columnar and square charging in turn,having obtained the peak overpressure at diverse scaling distances,acquired some representative simulation data and delivered a statistical chart to compare the differences between every group of peak overpressure data.It was shown that there was a closer peak overpressure generated from the columnar charging and the spherical with the scaling distance less than or equal to 1.0 m·kg^(-1/3),while that from the square charging and the spherical tending to a bigger difference.If the scaling distance was increasing,the ratio of peak overpressures almost kept stable from the columnar charging against the spherical,while that from the square charging against the spherical revealing gradually increasing and changing a lot.Evidently,shape-different charging does impact the generated shock-wave peak overpressure,deserving of no ignoring.Therefore,when investigating the charging with an actual explosive case and the consequent destroying effect,the explosion simulation should be carried out with the charging shape as close to the actual cases as possible.For exploration about the problems approaching to an explosion simulation,it is also necessary to choose the appropriate modeling way and charging setup so as to ensure the accuracy and reliability of the analysis and results.