The concrete structures under impact loading duress may be destroyed within an extremely short period of time. The importance and complexity of exploration on the impact resistance of concrete members make this area still open for discussion. In the present study, a 3-D mesoscale numerical model was established to investigate the effect of the combination of impact mass and velocity on the mechanical behavior of reinforced concrete (RC) beams subjected to impact loadings. Heterogeneity of concrete and strain rate effects of concrete and steel bars were taken into account. Furthermore, nonlinear interaction between the concrete and steel bars was considered herein. Results from macroscale and mesoscale simulation were compared with the available physical tests, indicating that the mesoscale numerical model can better represent the influence of heterogeneity of concrete on the mechanical behavior of RC beams. Five different impact energy levels were involved to study the effect of the combination of impact mass and velocity on the impact resistance of RC beams. At last, the residual bearing capacity and natural frequency of impacted RC beams were numerically calculated and their relationship was discussed. It is indicated that the deformation of RC beams is influenced strongly by the impulse, which increases with the increasing impact mass at identical impact energy. Besides, the failure mode of RC beams turns from shear-dominant failure mode to bending shear failure mode with the increase of impact mass, accompanied by the increase of energy dissipation of steel bars and the whole member. Despite this, in the present work, the combination of the impact mass and velocity had little influence on the damage extent (based on the performance) of the RC beams. Moreover, an empirical relationship between the residual bearing capacity and the natural frequency of the impacted RC beams was established as a rough reference for damage evaluation in engineering practice.

承受冲击载荷的混凝土结构可能会在极短的时间内被破坏。关于混凝土构件抗冲击性的探索的重要性和复杂性，使得该领域仍待讨论。在本研究中，建立了3-D中尺度数值模型来研究冲击质量和速度的组合对承受冲击载荷的钢筋混凝土（RC）梁的力学性能的影响。考虑到混凝土的非均质性以及混凝土和钢筋的应变率效应。此外，本文考虑了混凝土与钢筋之间的非线性相互作用。将宏观和中尺度模拟的结果与可用的物理测试进行了比较，表明中尺度数值模型可以更好地表示混凝土异质性对RC梁力学性能的影响。涉及五个不同的冲击能级，以研究冲击质量和速度的组合对RC梁抗冲击性的影响。最后，数值计算了受冲击RC梁的残余承载力和固有频率，并讨论了它们之间的关系。结果表明，在相同的冲击能量下，RC梁的变形受到冲击的强烈影响，随着冲击质量的增加而增加。此外，随着冲击质量的增加，钢筋混凝土梁的破坏模式从剪切为主的破坏模式转变为弯曲剪切破坏模式，同时钢筋和整个构件的能量耗散也随之增加。尽管如此，在目前的工作中，冲击质量和速度的组合对RC梁的损伤程度（基于性能）影响很小。此外，建立了残余承载力与受冲击RC梁固有频率之间的经验关系，作为工程实践中损伤评估的粗略参考。