湿筛混凝土试件的静、动破坏数值模拟

基于数字图像方法重构生成与真实骨料一致的混凝土骨料模型.混凝土各相材料的本构模型采用混凝土塑性损伤本构模型,考虑材料的应变软化,对湿筛混凝土试件的静、动破坏进行研究.研究结果表明:(a)混凝土的应力-裂缝宽度模型适用于骨料、砂浆和界面等各相材料.(b)随着应变率增加,混凝土的破坏形式明显由单条宏观裂纹向多条裂纹变化.(c)材料惯性对材料破坏荷载有一定影响,当应变率达到60s-1时材料的动力增强因子明显增大,惯性影响不可忽略；当应变率达到80s-1时材料惯性对材料破坏荷载影响较大；当应变率小于207.8 s-1时由率效应引起的动力强度增加大于由惯性效应引起的动力强度增加.

Numerical simulation of static and dynamic failure of wet-screened concrete specimen

Reconstruction of the internal structures for concrete composites was performed using digital imaging technology.With consideration of strain softening,the concrete plastic-damage model was adopted as the constitutive model for each material component to study the static and dynamic failure of the wet-screened concrete specimen.The results show the following:(a) The stress-crack width model is suitable for aggregate particles,cement matrix,and the interfacial transitional zone(ITZ).(b) With the increase of the strain rate,the failure mode of concrete transforms from single macro-cracks to multiple perforated cracks.(c) The inertia of material has an effect on the failure load.When the strain rate reached 60s-1,the dynamic increase factor(DIF) increased significantly,which indicates that the inertial effect cannot be neglected.When the strain rate reached 80 s-1,the inertial effect had a significant effect on the failure load.In addition,the increase of dynamic strength induced by the strain rate effect was greater than that induced by the inertial effect when the strain rate was less than 207.8s-1.