爆炸与冲击问题的大规模高精度计算

爆炸与冲击问题的数值模拟在国防和民用安全领域具有重要的工程实用价值.由于爆炸与冲击问题是一个多物质在高应变率、高温及高压条件下的强非线性的瞬态动力学问题,给数值模拟带来了很多的困难,为此,针对爆炸与冲击问题数值模拟中的一些关键和难点问题开展了研究.提出了三维非线性双曲守恒系统的伪弧长自适应网格算法,分析了算法的实现过程,数值结果表明该算法有效地提高了冲击波强间断处的分辨率.发展了针对气相爆轰数值模拟的附加龙格-库塔方法,对非线性对流项进行显示计算,化学反应源项进行半隐式计算,有效地解决了源项引起的刚性问题,计算结果表明该算法可以准确地捕捉和描述爆轰波的复杂结构和典型特征.针对三维工程实际物理问题中的大规模计算需求,给出了三维多物质流体动力学欧拉数值方法的并行化方法,开发了三维爆炸与冲击问题并行计算程序,并给出了针对该并行程序的测试方法.上述工作有利地解决了爆炸与冲击问题大规模、高精度计算中的一些难题.最后,开展了大口径聚能射流侵彻混凝土靶问题的数值模拟和实验研究,通过典型爆炸与冲击工程问题的计算验证了所研究数值方法的有效性.

LARGE SCALE HIGH PRECISION COMPUTATION FOR EXPLOSION AND IMPACT PROBLEMS

Numerical simulations of explosion and impact problems have important engineering application value in the fields of national defense and civil security. Numerical simulations for these problems have a lot of difficulties because the explosion and impact problems are strongly nonlinear transient dynamic problems in which multi-material mechan-ical behaviors are involved under the condition of high strain rate, high temperature and high pressure. Therefore, in this paper , the pseudo arc-length method for 3D nonlinear hyperbolic conservation system is proposed and the process of the algorithm realization is analyzed. The numerical results show that the algorithm improves the resolution of the shock wave strong discontinuity effectively. The additive Runge-Kutta method for gaseous detonation numerical simula-tion is developed. In this method, the nonlinear convection part is solved implicitly while the chemical reaction source part is handled explicitly. The results show that the additive Runge-Kutta method can well capture and accurately de-scribe the complex structure and typical characteristics. The parallel Eulerian numerical method of 3D multi-material hydrodynamics is investigated for the requirement of large-scale computation in engineering practical physical problems. The 3D explosion and impact problem parallel computation hydrocode is developed and the test method for this parallel hydrocode is proposed. According to the above works, some problems of large-scale and high-precision calculations for explosion and impact problems are solved. Finally, the experimental and numerical investigations on heavy-caliber shaped-charge penetration in thick concrete target are carried out, and the effectiveness of the proposed numerical method is demonstrated by typical explosion and impact engineering problems.