可变形异型弹体撞击高强度岩石实验

Deformable Special-Shaped Projectile Impacting a High-strength Rock:Experiments and Analysis

发射弹体作为激励物破碎高强度岩石实现样品采集在近地小行星(NEA)取样方案中备受关注。为研究可变形异型弹体撞击高强度岩石的弹靶作用过程及岩石破碎机理,设计花瓣形贯穿式、花瓣形非贯穿式与圆卵形贯穿式3类弹体,基于57 mm轻气炮和14.5 mm弹道枪开展低速(71.4~280.0 m/s)与高速(453.0~612.0 m/s)撞击单轴抗压强度180 MPa高强度玄武岩实验,获得不同构型和入射速度下弹体变形模式、反射速度及反射动能比、岩石破碎区直径、开坑深度及碎岩质量变化规律。实验结果表明:低速撞击下,两类花瓣形弹体的反射速度较圆卵形弹体降低了约21.9%~42.8%,且具有更低的反射动能比;高速撞击下,花瓣形非贯穿式弹体的弹靶作用过程为多点同步撞击与泰勒杆式撞击两段式过程,其碎岩质量约为花瓣形贯穿式弹体的3倍。研究结果为可变形异型弹体构型设计、高强度岩石破碎机理研究提供实验验证与研究思路。

Fracturing a high-strength rockto collect the fragment samples by the kinetic energy of deformable special-shaped projectile has attracted much attention in the Near-Earth Asteroid(NEA) sampling scheme.Three types of deformable special-shaped projectiles,i.e.,petal penetrating,petal non-penetrating and oval penetrating,are designed to study theprojectile-target interaction and rock fracture mechanism.Based on 57 mm lightgas gun and 14.5 mm ballistic gun,the low-speed(71.4-280.0 m/s) and high-speed(453.0-612.0 m/s) impact experiments are carried out for a rock with uniaxial compression strength of 180 MPa to obtain the reflected velocity of projectile,mass of rock fragments,and diameter and depth of fracturing zone.Experimental results show that,in the low-speed impact experiments,two types of petal projectiles have lower reflected kinetic energy ratio and its reflection speed is reduced by 21.9%-42.8% compared to other projectiles;In the high-speed impact experiments,the projectile-target interaction of petal projectile is two-phase processes:multi-point simultaneous impact and Taylor rod impact,which increase the mass of fragments about three times than petal penetrating projectiles.The research inspires the designing of deformable special-shaped projectile and the comprehending of fracture mechanism of rocks under impact.