Dynamic failures (e.g., crater, crack and spall) can be observed in concrete structures when suffered from possible blast and impact loadings. Understanding the physical mechanisms behind these failures needs a sound material model that thoroughly considers the damage mechanisms of concrete material, especially under the high confinement situation existed near the projectile and explosion. Modelling the damage mechanisms is a challenging problem that is not fully resolved in the commonly-used concrete material models. In this study, three kinds of damage mechanisms of concrete material, i.e., the hydrostatic damage due to pore collapse, shear damage due to shear-induced microcracking and tensile damage due to tensile microcracking are identified and physically modelled respectively using corresponding damage indexes. The interaction of the three damage is also considered by introducing two stress-dependent factors. The damage model is implemented into the Kong-Fang material model recently proposed, in which improvements on the strength surfaces, strain-rate enhancement and erosion criterion are accompanied made based on a few years use of this model. Numerical triaxial compression test and hydrostatic compression to unconfined compression test are conducted using a single element to validate the proposed hydrostatic damage model and the shear damage model. And the competition mechanism between hydrostatic damage and shear damage during the triaxial compression test is discussed. Then the modified Kong-Fang model is used to numerically simulate the reinforced concrete slabs subjected to a contact explosion load and projectile impact load, in which the physical mechanisms of the experimentally observed crater, crack, tunnel and spall failures are revealed.

当遭受可能的爆炸和冲击载荷时，可以在混凝土结构中观察到动态破坏（例如，弹坑，裂缝和剥落）。了解这些破坏背后的物理机制需要一个合理的材料模型，该模型应充分考虑混凝土材料的破坏机理，尤其是在弹丸和爆炸附近存在高约束条件的情况下。对损坏机制进行建模是一个具有挑战性的问题，在常用的混凝土材料模型中无法完全解决。在这项研究中，分别确定了混凝土材料的三种破坏机理，即孔洞塌陷引起的静水破坏，剪切引起的微裂纹引起的剪切破坏和拉伸微裂纹导致的拉伸破坏，并分别使用相应的破坏指数进行了物理建模。通过引入两个应力相关因素，还可以考虑三种损伤的相互作用。损伤模型被应用到最近提出的空方材料模型中，该模型在几年使用的基础上，对强度表面，应变率增强和腐蚀准则进行了改进。使用单个元素进行了数值三轴压缩试验和静水压缩至无边压缩试验，以验证所提出的静水破坏模型和剪切破坏模型。讨论了三轴压缩试验中静水损伤与剪切损伤的竞争机理。然后使用改进的Kong-Fang模型对钢筋混凝土平板进行接触爆炸载荷和弹丸冲击载荷的数值模拟，