双石英玻璃珠的低速冲击破碎行为

应用分离式霍普金森压杆(SHPB)加载装置,对直径为8.30、11.68、15.42、17.50 mm的石英玻璃珠开展了冲击速度为5.6~11.5 m/s的双玻璃珠系动态破碎实验。利用高速摄影技术记录双玻璃珠在动态冲击下的破碎过程,结合透射载荷-位移曲线以及破碎产物的粒度分析结果,探讨了石英玻璃双颗粒在冲击下的破坏机制。结果表明:由于双颗粒系中载荷的不均匀特性,两个玻璃珠的破碎具有时序特征,随冲击速度的增加而改变;玻璃珠的冲击破碎源于接触部位局部的Hertz裂纹扩张和裂纹系的扩散,而不是通常认为的贯穿性的斜裂纹体系;瞬态红外测温揭示了玻璃珠冲击破碎的两种主要机制和临界破碎扩散阻力的存在。研究结果对认识脆性颗粒介质的动态破坏机制具有良好的参考意义。

Fragmentation of Double Quartz Glass Spheres Subjected to Lower-Velocity Impact

By employing a split Hopkinson pressure bar(SHPB)device,the dynamic crushing experiments of quartz glass beads with diameters of 8.30,11.68,15.42 and 17.50 mm,were implemented with impact velocity of 5.6–11.5 m/s.High-speed photographing technology was used to record the crushing process of double glass beads during impact.Combined with the transmitted load-displacement curves and the results of particle size distribution analysis,the failure mechanism of quartz glass under double-particle impact was discussed.Due to the non-uniform load distribution in the double-particle system,the breakage of two glass beads demonstrated a time-varying characteristic,which changed with the increasing impact velocity.Despite of the conventional penetrating oblique crack system,the impact fracture of glass beads was caused by the local Hertz crack expansion and the crack system diffusion at the contact points.The fast infrared temperature measurement revealed two main fracture mechanisms and the existence of critical crushing diffusion resistance.This work has shown to be a significant reference for understanding the dynamic failure mechanism of brittle granular matter.