【摘要】 目前对超高韧性水泥基复合材料(PVA-UHTCC)动态增强机理的认识多停留在宏观层面，尤其缺乏对纤维与基体在高速冲击下细观相互作用深刻理解的难题，笔者从细观尺度揭示PVA纤维在冲击荷载下的增强机制。采用ABAQUS有限元模拟分析软件调用HJC本构模型对PVA-UHTCC进行宏观SHPB冲击压缩过程数值模拟，再利用Python二次开发技术建立能反映PVA纤维随机分布的三维二相细观模型，并考虑纤维与基体间的粘结滑移关系。宏观模拟结果与ANSYS有限元模拟分析软件结果吻合良好，准确再现了5种应变率下的动态压缩破坏过程，验证了ABAQUS有限元模拟分析软件模拟的正确性；建立的三维细观模型成功模拟了冲击荷载下PVA纤维对基体变形的约束作用及其桥接增强效果。该研究验证了基于ABAQUS有限元模拟分析软件进行PVA-UHTCC动态冲击模拟的可行性，并构建了能够揭示纤维增强机理的细观有限元模型，为该类材料的细观破坏机理和动态性能研究奠定了基础。更多还原

【Abstract】 Currently, the understanding of the dynamic enhancement mechanism of ultra-high toughness cement-based composites(PVA-UHTCC) is largely at the macroscopic level, particularly lacking a deep understanding of the mesoscopic interactions between fibers and the matrix under high-speed impact.In this paper, the author reveals the enhancement mechanism of PVA fibers under impact loading at the mesoscopic scale.Using the ABAQUS finite element analysis software, the HJC constitutive model is first invoked to simulate the macroscopic SHPB impact compression process of PVA-UHTCC.Then, Python secondary development technology is used to establish a three-dimensional biphasic mesoscopic model that reflects the random distribution of PVA fibers, while considering the bond-slippage relationship between the fibers and the matrix.The macroscopic simulation results are in good agreement with those from ANSYS,accurately reproducing the dynamic compression failure process at five different strain rates, thus verifying the correctness of the ABAQUS simulation.The established three-dimensional mesoscopic model successfully simulates the constraint effect of PVA fibers on matrix deformation and their bridging reinforcement effect under impact loading.This study verifies the feasibility of conducting dynamic impact simulations of PVA-UHTCC using ABAQUS and successfully constructs a mesoscopic finite element model that reveals the fiber reinforcement mechanism, laying the foundation for further research on the mesoscopic failure mechanism and dynamic performance of such materials.更多还原