摘要
对不同速度弹丸撞击花岗岩靶产生的弹坑深度和裂纹长度进行实验和数值分析。利用轻气炮进行五发实验,得到3种撞击速度下的弹坑直径、弹坑深度、靶板表面裂纹分布等破坏效应,并对撞击速度为654 m/s的正侵彻实验靶进行切割,得到靶板内部的裂纹分布情况。采用非线性动力学软件Autodyn对正侵彻花岗岩实验进行数值模拟。将Johnson-Homquist损伤本构模型(JH–2模型)与拉伸断裂软化模型相耦合,来模拟靶板内高应力区材料的压缩和剪切破坏效应,以及低应力区靶板在主拉伸应力作用下产生的损伤和裂纹扩展。相对于传统有限元计算中删除单元形成裂纹的处理方法,本文采用SPH算法,通过定义损伤来描述材料的压缩破坏以及由剪切和拉伸断裂形成的裂纹。模拟得到的弹坑尺寸以及裂纹长度与实验结果符合较好。根据模拟结果进行数值试验,拟合出不同撞击速度下的弹坑深度和裂纹长度的经验关系式。相关方法及材料模型参数可为后继实验和相关数值模拟提供参考。
The crater depth and crack length of granite targets impacted by different velocity projectiles were studied with experimental and numerical methods. Five experiments were carried out by gas gun. The crater diameter,maximum penetration depth,distribution of cracks on target surface and the other destructive effects were obtained from the experiments at three different impact velocities. The distribution of inner cracks was attained with the help of cutting target normally impacted by the projectile at the velocity of 654 m/s. Nonlinear dynamic software Autodyn was used to simulate the penetration destructive effects of granite target. Johnson-Holmquist shock damage constitutive model（JH-2 model） and tensile crack softening model were coupled together to simulate the compressive and shear destructive effects in high pressure region,and the damage and propagation of radial tensile cracks generated by the principal tensile stress in low pressure region. Instead of traditional elements-deleting methods in FEM,the arithmetic of SPH was used and the parameter of damage was defined to describe the failure of compression and the cracks induced by shear and tensile failure. The simulation results about crater depth and crack length are consistent with the experimental ones. Based on numerical validated model parameters,serious numerical experiments were implemented;and formulae about crater depth and crack length of granite targets under the impact of different velocity projectiles were obtained. The method and the＆amp;nbsp;validated material model parameters used in this paper could be referenced by relevant experiments and simulations.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2014年第2期366-375,共10页
Chinese Journal of Rock Mechanics and Engineering
