摘要
高压状态方程是研究材料在爆炸冲击作用下破坏机制及冲击波传播规律的基础,岩石高压状态方程在矿山开采、陨石冲击成坑、岩体冲击防护等数值计算方面有着广泛的应用需求.基于二级轻气炮发射平台和光子多普勒测速系统,采用平板撞击研究了红砂岩的Hugoniot冲击关系、高压状态方程和体应变方程.平板撞击实验最低速度为0.88 km/s,最高至1.97 km/s,碰撞产生的最低冲击压力为7.2 GPa,最高冲击压力为19.4 GPa.采用光探针测量岩样的冲击波速度,光子多普勒测速系统记录的自由面质点速度剖面未出现红砂岩的Hugoniot弹塑性转变点,表明在此冲击压力范围内红砂岩为近流体状态.采用最小二乘法对冲击波速度D和质点速度u进行线性拟合,获得红砂岩的冲击Hugoniot参数分别为C0=3.04和λ=1.14.采用三次多项式对红砂岩体应变η与冲击压力P进行非线性拟合,获得红砂岩体应变η与冲击压力P之间的关系式为P=116η-745η2+1845η3,非线性拟合系数R=0.993.冲击加载下红砂岩Hugoniot状态方程和体应变方程可为红砂岩岩体爆破、岩体冲击防护等领域的数值计算和工程应用提供基础参考数据.
Abstract
The high-pressure equation of state is the basis of studying the failure mechanism of materials and the propagation law of shock waves under explosion or impact loading.The state of rock has a wide range of applications in the numerical calculation of mining,meteorite impact cratering,rock impact protection,etc.Using a two-stage light gas gun and Photon Doppler Velocimeter(PDV),the Hugoniot relationship,high-pressure equation of state and volume strain equation of red sandstone were studied.The lowest and the highest impact pressure generated by the collision were 7.2 GPa and 19.4 GPa,respectively,and the lowest and the highest planar impact velocity were 0.88 km/s and 1.97 km/s,respectively.At the same time,optic probes were used to measure the shock wave velocity of rock sam-pies.However,The Hugoniot-Elastic-Limit(HEL)point of the red sandstone was not found in the free surface veloci-ty profile recorded by the PDV,indicating that the red sandstone was in a near-fluid state within this impact pressure range.Furthermore,the shock wave velocity D and particle velocity u were linearly fit by the least square method,and the Hugoniot parameters of the red sandstone were C0=3.04 and λ=1.14,respectively.In addition,the relationship between the volumetric strain η and the impact pressure P were obtained by polynomial fitting,which was P=116η-745 η2+1845η3,and the nonlinear fitting coefficient was 0.993.The Hugoniot equation of state and bulk strain equation of red sandstone obtained in this work can provide reference data for numerical calculation and engi-neering application in red sandstone rock blasting,shock protection engineering,and so on.
维普
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