Lu Hui, Pan Yue, He Kang, Wang Fei, Gao Lei, Pu Shikun, Li Erbing
College of Field Engineering, Army Engineering University of PLA, Nanjing 210007, China.
College of Transportation Engineering, Tongji University, Shanghai 200092, China.
Materials (Basel). 2023 Jul 26;16(15):5235. doi: 10.3390/ma16155235.
To study the dynamic mechanical properties and damage evolution mechanism of Beishan deep granite under medium and high strain rates, dynamic mechanical tests for the deep granite specimens with different strain rates were conducted using the split Hopkinson pressure bar (SHPB) device. The improved Zhu-Wang-ang (ZWT) dynamic constitutive model was established, and the relationship between strain rate and strain energy was investigated. The test results show that the strain rate in the dynamic load test is closer to the strain rate in the rock blasting state when the uniaxial SHPB test is applied to the granite specimens in a low ground stress state. Peak stress has a linear correlation with strain rate, and the dynamic deformation modulus of the Beishan granite is 152.58 GPa. The dissipation energy per unit volume and the energy ratio increase along with the strain rate, whereas the dissipation energy per unit volume increases exponentially along with the strain rate. There is a consistent relationship between the damage degree of granite specimens and the dissipation energy per unit volume, which correspond to one another, but there is no one-to-one correspondence between the damage degree of granite specimens and the strain rate. To consider the damage and obtain the damage discount factor for the principal structure model, the principal structure of the element combination model was improved and simplified using the ZWT dynamic constitutive model. The change of damage parameters with strain rate and strain was obtained, and the dynamic damage evolution equation of Beishan granite was established by considering the damage threshold.
为研究北山深部花岗岩在中高应变率下的动态力学性能及损伤演化机制，利用分离式霍普金森压杆（SHPB）装置对不同应变率的深部花岗岩试样进行了动态力学试验。建立了改进的朱-王-昂（ZWT）动态本构模型，研究了应变率与应变能之间的关系。试验结果表明，在低地应力状态下对花岗岩试样进行单轴SHPB试验时，动态载荷试验中的应变率更接近岩石爆破状态下的应变率。峰值应力与应变率呈线性相关，北山花岗岩的动态变形模量为152.58 GPa。单位体积耗散能和能量比随应变率的增加而增大，而单位体积耗散能随应变率呈指数增加。花岗岩试样的损伤程度与单位体积耗散能之间存在一致的对应关系，但花岗岩试样的损伤程度与应变率之间不存在一一对应关系。为考虑损伤并获得主结构模型的损伤折减系数，利用ZWT动态本构模型对单元组合模型的主结构进行了改进和简化。得到了损伤参数随应变率和应变的变化规律，考虑损伤阈值建立了北山花岗岩的动态损伤演化方程。
