界面弹性模量对混凝土梁影响的三维动态研究

Three-dimensional dynamic study on the influence of interfacial elastic modulus on concrete beam

采用Weibull统计学理论模拟混凝土材料的非均匀分布,对钢筋混凝土梁界面弹性模量变化对梁裂纹扩展的影响进行研究,得到了试件从裂纹萌生、扩展直至贯通的破坏全过程图和峰值荷载曲线、声发射曲线。结果表明:钢筋混凝土梁界面弹性模量的变化对梁的裂纹扩展模式有着较为显著的影响;随着试件界面弹性模量的增加,试件的破坏模式从以弯曲裂纹为主的弯曲拉裂破坏逐步变化为以斜裂纹为主的剪切破坏。试件的峰值荷载以及累积声发射次数随界面弹性模量的增大均呈现先增大后减小的规律;其中试件的累积声发射次数曲线有三个明显的"突变点";同时不同试件在破坏过程中的加载步-声发射数柱状图都存在着4个极值点,它们分别对应试件不同的破坏阶段。

The influence of interfacial elastic modulus of reinforced concrete beams on crack propagation has been simulated in this paper. Non-uniform distribution of Weibull statistical theory has been adopted when setting concrete model. The failure process diagrams of crack initiation,propagation and penetration,peak load curve and acoustic emission(AE)curve have been obtained. The results show that variation of interfacial modulus has a significant influence on the crack propagation pattern,with increase of the interface elastic modulus of specimens,failure pattern of the specimen gradually changes from bending tensile failure dominated by bending cracks to shear failure dominated by oblique cracks. Both peak load of tested beams and accumulative AE events increase first and then decrease with the increase of interfacial modulus. There are three obvious"jump points"in the cumulative AE curve and four extreme points in the histogram of AE events of each specimen,respectively,which correspond to different failure stages,respectively.