石英玻璃球撞击刚性壁的破碎过程

利用高速枪对石英玻璃球撞击刚性靶板进行了实验研究,分析了不同速度下球体的破碎过程和失效模式。当冲击速度低于临界破坏速度时,石英玻璃球以略低于原速从靶板回弹;当超过临界破坏速度时,球体呈现“压缩破碎区-表面剥落区-剪切破坏区”的破坏结构;进一步提高碰撞速度,剪切破坏区的扩展导致球体碎裂为若干“月牙状”的碎块;更高撞击速度下,石英玻璃球发生坍塌式破碎,在远离撞击端处产生层裂现象。利用离散元软件对球体的撞击破坏过程进行了模拟研究,球体在高速碰撞下的破碎可以分为弹性压缩、整体破碎和二次撞击3个阶段。球体碎裂前Hertz接触理论可以较好描述其撞击力,而破碎后的撞击力由于碎裂卸载远小于理论值,且偏差随冲击速度逐渐增加。

Fragmentation Process of Quartz Glass Spheres Impacting Rigid Wall

The high-speed gun is used to study the impact of quartz glass ball on rigid target plate.The crushing process and failure mode of the ball at different speeds are analyzed.When the impact velocity is lower than the critical failure velocity,the quartz glass ball rebounds from the target plate,and the rebounding speed is slightly below the original speed;when the critical speed is exceeded,the sphere exhibits a“compressed fracture zone–surface spalling zone–shear failure zone”failure structure;further increasing the collision velocity,the expansion of the shear failure zone causes the sphere to be fragmented into several“crescent”fragments.At higher impact speeds,the quartz glass ball collapses and spalls at a distance away from the impact end.Furthermore,the discrete element software is utilized to simulate the impact damage process of the sphere.The crushing of the sphere under high-speed collision can be divided into three stages:elastic compression,integral crushing,secondary impact.Before the ball breaks,the Hertz contact theory can describe its impact force well,but the crushing force is much smaller than the theoretical value due to the fracture unloading,and the deviation gradually increases with the increasing impact speed.