基于SPH方法的爆炸压实孔隙塌缩模拟

Explosive compaction pore collapse simulation based on SPH method

SPH无网格方法适用于大变形问题的数值模拟,近年来一直是研究的热点。爆炸压实过程中孔隙的闭合程度对压实效果起着至关重要的作用。运用AUTODYN软件中的SPH方法对爆炸压实中颗粒间的孔隙闭合过程进行模拟,将模型简化为密排球堆模型中的正三角孔隙闭合模型与倒三角孔隙闭合模型。模拟铜颗粒的孔隙闭合,选用Johnson-Cook本构模型和Hugoniot冲击关系,加载条件为速度加载。根据数值模拟得到的应力分布图、速度分布图、大塑性变形及碰撞点切线的速度分布曲线,可以得出爆炸压实过程中存在着微爆炸焊接、微摩擦焊接、射流侵彻、大塑性变性等过程。不同的孔隙闭合方式下所产生的沉能机制与理论分析得出的相符合。

SPH meshless numerical simulation method is suitable for studying large deformation problems.It has been a research focus in recent years.During explosive compaction,pore collapse plays a vital role on consolidation.AUTODYN software SPH method was used to simulate the process of explosive compaction.The model was simplified as equilateral triangle closed pore model and inverted triangle structure closed pore model in ball accumulation model.The material was copper powder,Johnson-Cook constitutive model,Hugoniot shock relations,and speed loading condition were adopted.Stress distribution velocity profile,large plastic deformation and velocity profile of collision point in the tangential were obtained by the numerical simulation.It indicated that micro-welding,micro-friction welding,high-speed jet and large plastic deformation existed in the process.The simulation results were consistent with the theoretical analysis.