碎片云SPH方法数值模拟中的材料失效模型

Material failure models in SPH simulation of debris cloud

光滑粒子流体动力学方法(smoothed particle hydrodynamics,SPH)被广泛应用于薄板超高速撞击碎片云的数值模拟。利用AUTODYN软件中的SPH模块,考察了无失效模型、Grady失效模型和最大拉应力失效模型3种方案下碎片云模拟结果,发现无失效模型时计算结果及材料表现与实验明显不符;相比于Grady失效模型,最大拉应力失效模型下材料更难失效,将小幅度减弱碎片云扩散程度,碎片总数减少,粒子聚集产生更大碎片,碎片云侵彻性能提高,增大模型失效阈值亦有上述表现。相比而言,Grady失效模型计算结果更符合实验,但2种失效模型间差异与撞击工况相关,材料破碎越充分差异越小。

The smoothed particle hydrodynamics(SPH)method is widely used in debris cloud simulation under hypervelocity impact.The SPH solver in AUTODYN was employed to investigate the effects of the no-failure model,the Grady failure model and the maximum tension failure model on the simulation results of debris cloud.When using the no-failure model,the simulation result and material response were not consistent with the experiment.Compared with the Grady model,the material under the maximum tension model was more difficult to fail,which would slightly weaken the expansion of debris cloud,produce less but heavier debris because of particles gathering,and thus improve the penetration performance of debris cloud.Similarly,by increasing the failure stress threshold,the above result was also obtained.Considering the material response and debris distribution,the simulation result by the Grady model was closer to the experiment.However,the difference between the Grady model and the maximum tension model was related to the impact condition,and more complete fragmentation of the material would lead to a smaller difference.