砂浆材料SHPB实验及惯性效应的数值模拟研究

进行了砂浆材料在不同应变率下的SHPB实验，拟合实验数据得到了动态强度放大因子DIF随应变率变化的关系曲线。基于实验测得应变率时程曲线，采用简化有限元模型，对实验进行了数值模拟。该文探讨了动态压缩实验中惯性效应产生的原因，并基于数值模拟对本实验中惯性效应对材料动态强度的影响进行了剥离，得到了砂浆材料动态强度放大因子随应变率变化的固有特性曲线，并将该固有特性曲线作为数值模拟中应变率效应的输入，计算结果与实验得到的应力-应变曲线吻合较好。进一步通过比较输入CEB推荐曲线和已有半经验公式的模拟结果，验证了所提出砂浆材料动态强度放大因子固有特性曲线的优越性。

SHPB TEST AND NUMERICAL INVESTIGATION ON THE INERTIA EFFECT OF MORTAR MATERIAL

The dynamic compressive properties of mortar material at different strain-rates are experimentally investigated by split Hopkinson pressure bar (SHPB) test, in which the relationship between the dynamic increase factor (DIF) and strain-rate is obtained. Numerical simulations using a simplified model are conducted based on the strain rate curve obtained from experiments. The principle of the unavoidable inertia effect known as the "structure effect" in dynamic compressive tests is discussed. To obtain the inherent DIF of mortal material subjected to high strain-rate, numerical simulations are conducted to eliminate the inertia effect. It is found that the predicted stress-strain curves in the numerical simulation agree well with the corresponding experimental data when the above-mentioned inherent DIF is used as the numerical input. Furthermore, the superiorities of the proposed inherent DIF are validated by comparing the CEB recommended DIF and existing semi-empirical DIF as the numerical inputs.