用于诊断材料微层裂的Asay窗技术

微层裂是冲击波物理领域的重要基础问题,在工程上具有重要应用价值。近年来用于诊断样品多层层裂的传统Asay窗技术被用于诊断微层裂,但对其诊断能力和信号特征认识仍存在严重不足。为此,通过波系分析,揭示出在薄飞片击靶的微层裂实验中样品破碎存在1个“痂片”特征区、2个微层裂特征区以及1个“残体”特征区。实验表明,在样品窗口间隙合适的条件下,Asay窗不仅能够有效区分这些不同特征分区,而且能够灵敏探测样品表面发射的高速微喷粒子,从而实现对样品连续破碎过程的精密诊断。     

An improved model of damage depth of shock-melted metal in microspall under triangular wave loading

Damage depth is an important dynamic parameter for describing the degree of material damage and is also a key fundamental issue in the field of impact compression technology. The present work is dedicated to the damage depth of shock-melted metal in microspall under triangular wave loading, and an improved model of damage depth considering the material's compressibility and relative movement is proposed. The damage depth obtained from the proposed model is in good agreement with the laser-driven shock loading experiment. Compared with the previous model, the proposed model can predict the damage depth of shock-melted metal in microspall more accurately. Furthermore, two-groups of the smoothed particle hydrodynamics(SPH) simulations are carried out to investigate the effects of peak stress and decay length of the incident triangular wave on the damage depth, respectively. As the decay length increases, the damage depth increases linearly. As the peak stress increases, the damage depth increases nonlinearly, and the increase in damage depth gradually slows down. The results of the SPH simulations adequately reproduce the results of the proposed model in terms of the damage depth. Finally, it is found that the threshold stress criterion can reflect the macroscopic characteristics of microspall of melted metal.     

激光加载锡的动态破碎颗粒尺寸分布

基于Grady能量破坏准则,结合固体动态断裂碎块尺寸分布规律研究结果,提出了材料微层裂破碎颗粒质量分布改进模型,并对强激光加载下锡的熔化破碎实验进行了理论计算。研究显示,理论计算的锡的微层裂破碎颗粒分布数随直径变化规律与实验结果一致,模型进一步改进需考虑应变率变化等更多综合因素影响。