摘要
利用分离式霍普金森压杆(SHPB)试验系统,对系列波阻抗的模型材料进行不同应变率下的冲击压缩试验。试验结果表明:岩石在冲击荷载下的应力波传播特征、动态应力应变关系以及破碎块度分形特征同时受波阻抗、应变率和冲击速度的影响。波阻抗相同时,反射波和透射波信号幅值均随冲击速度增大呈线性增大,同时应变率效应明显,随着应变率的增大:峰值应力呈线性增大,动态弹性模量增大,应变软化阶段延长;破碎程度增大,破碎块度分形维数呈线性增大。应变率相同时,随着波阻抗的减小:反射波幅值增大、透射波幅值减小;峰值应力减小,应变软化阶段延长,塑性段趋于明显,且有塑性流动现象出现;破碎程度增大,破碎块度分形维数增大。同时随着波阻抗减小,应变率增大对动态抗压强度的增大以及对破碎程度的加剧效果减弱,应变率效应减弱,逐渐趋于不明显。
A series of impact compression tests were conducted on model materials with different wave impedances under different strain rates using the split-Hopkinson pressure bar(SHPB)test system.The test results showed that under impact load,rock’s stress wave propagation characteristics,dynamic stress-strain relation and fractal features of rock fragmentation are affected by wave impedance,strain rate and impact velocity;when wave impedance is the same,amplitudes of reflected wave and transmitted one increase linearly with increase in impact velocity;at the same time,effect of strain rate is obvious,with increase in strain rate,peak stress increases linearly,dynamic elastic modulus increases,and strain softening stage prolongs;when crushing degree increases,fractal dimension of fragmentations increases linearly;when strain rate is the same,with decease in wave impedance,amplitude of reflected wave increases and transmitted one’s decreases;when peak stress decreases,strain softening stage prolongs,plastic stage tends to be obvious,and plastic flow phenomenon appears;when crushing degree increases,fractal dimension of fragmentations increases;with decrease in wave impedance,effect of increase in strain rate on increase in dynamic anti-compression intensity and enhancing degree of crushing weakens,strain rate’s effect weakens and gradually tends to be unconspicuous.
作者
杨仁树
李炜煜
方士正
朱晔
李永亮
郑昌达
YANG Renshu;LI Weiyu;FANG Shizheng;ZHU Ye;LI Yongliang;ZHENG Changda(School of Mechanics and Architecture Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;State Key Laboratory for Geomechanics and Deep Underground Engineering,Beijing 100083,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2020年第3期178-185,共8页
Journal of Vibration and Shock
基金
国家重点基础研究发展计划(2016YFC0600903)
高等学校学科创新引智计划“111计划”(B14006)
关键词
波阻抗
应变率
分离式霍普金森压杆
应力波
动态力学性能
块度分维
wave impedance
strain rate
split Hopkinson pressure bar(SHPB)
stress wave
dynamic performance
fractal dimension of fragmentation
