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本文以被动围压下混凝土分离式霍普金森压杆(Split Hopkinson Pressure Bar,简称SHPB)试验为基础,采用有限元软件ANSYS/LS-DYNA建立了钢质套管约束下混凝土SHPB试验的数值模型,通过对比分析20组不同围压、不同应变率下混凝土的动态力学性能,得到了围压和应变率对混凝土破坏形态、应力-应变曲线、极限强度、峰值应变等的影响规律。结果表明:随着应变率的增大,混凝土的破坏形态逐渐从劈裂破坏转变为压碎破坏,且围压越大,混凝土的强度发挥得越充分;当应变率从01s-增大到126.471s-时,无围压状态下混凝土的动态强度增长因子和动态应变增长因子分别提高到2.74和1.95,被动围压下动态强度增长因子和动态应变增长因子分别提高到1.93和1.39;在围压为0MPa~6.93MPa的范围内,混凝土动态极限强度随围压增大而提高的幅度是有限的,且在围压为4MPa左右时趋于稳定,而混凝土的围压应变增长因子随围压的增大基本呈线性提高。
Based on the Split Hopkinson Pressure Bar (SHPB) test under passive confining pressure, the numerical model of SHPB under steel casing constraint was established by finite element software ANSYS / LS-DYNA By comparing the dynamic mechanical properties of concrete under different confining pressure and different strain rates, the effects of confining pressure and strain rate on the failure mode, stress-strain curve, ultimate strength and peak strain of concrete are obtained. The results show that as the strain rate increases, the failure morphology of concrete gradually changes from cleavage failure to crushing failure, and the greater the confining pressure, the more fully the strength of concrete becomes. When the strain rate increases from 01s to 126.471 s-, the dynamic strength growth factor and dynamic strain growth factor of concrete under confining pressure were increased to 2.74 and 1.95 respectively, the dynamic strength growth factor and dynamic strain growth factor under passive confining pressure increased to 1.93 and 1.39 respectively. For the range of 0MPa ~ 6.93MPa, the dynamic ultimate strength of concrete increases with confining pressure is limited and the stability tends to be stable when the confining pressure is about 4MPa, while the compressive strain growth factor of concrete with confining pressure Increase the basic linear increase.