Zhang Wei, Mao Jize, Yu Xiao, Zhou Bukui, Wang Limei
College of Aerospace and Civil Engineering, Harbin Engineering University, Harbin 150001, China.
Institute of Defense Engineering, Academy of Military Sciences, Beijing 100850, China.
Materials (Basel). 2023 Oct 7;16(19):6591. doi: 10.3390/ma16196591.
To confirm the effect of confining pressure on the dynamic mechanical behavior of ultrahigh-performance concrete (UHPC), this study used a true triaxial split Hopkinson pressure bar test system to perform dynamic compression tests on UHPC under triaxial constraints. The confining pressure range considered was 510 MPa, the strain rate range was 3580 s, and the steel fiber contents were 0.5%, 1% and 2%. The three-dimensional dynamic engineering stress-strain relationship and equivalent stress-strain relationship of UHPC under different confining pressures and different strain rates were obtained and analyzed in detail. The results show that under the confinement condition, the dynamic peak axial stress-strain and dynamic peak lateral stress-strain of UHPC have strong sensitivity to the strain rate. In addition, the dynamic peak lateral stress-strain is more sensitive to the confining pressure than the dynamic axial stress. An empirical strength enhancement factor (DIFc) that considers the strain rate effect and confining pressure was derived, and the impact of the coupling between the enhancement caused by the confining pressure and the strain rate effect on the dynamic strength of the UHPC under triaxial confinement was discussed. A dynamic strength failure criterion for UHPC under triaxial constraint conditions was established.
为了确定围压对超高性能混凝土（UHPC）动态力学性能的影响，本研究采用真三轴分离式霍普金森压杆试验系统对UHPC在三轴约束下进行动态压缩试验。考虑的围压范围为510MPa，应变率范围为3580s，钢纤维含量分别为0.5%、1%和2%。详细获得并分析了不同围压和不同应变率下UHPC的三维动态工程应力-应变关系和等效应力-应变关系。结果表明，在约束条件下，UHPC的动态峰值轴向应力-应变和动态峰值横向应力-应变对应变率具有较强的敏感性。此外，动态峰值横向应力-应变比动态轴向应力对围压更敏感。推导了考虑应变率效应和围压的经验强度增强因子（DIFc），并讨论了围压引起的增强与应变率效应之间的耦合对三轴约束下UHPC动态强度的影响。建立了三轴约束条件下UHPC的动态强度破坏准则。
