【摘要】 为分析不同配筋混凝土梁受弯破坏过程裂缝发展特征，探讨梁体破坏声发射特性及抗弯性能退化规律，采用四点弯曲试验，结合声发射技术，建立三种不同配筋混凝土梁受弯破坏过程与声发射信号的联系。实验结果表明，不同配筋混凝土梁损伤演化过程中的上升角(rise time/maximum amplitude, RA)、平均频率(average frequency, AF)信号具有明显差异，适筋梁、少筋梁、超筋梁剪切裂缝信号RA占比77.6%、80.9%、78.95%远高于斜拉裂缝信号AF占比，混凝土梁破坏以剪切破坏为主。不同配筋梁弯曲损伤各阶段振幅分布的共同特征主要由频率区间4～6 kHz、13.5～16 kHz以及53～57 kHz的振幅峰值体现，梁体达到特殊荷载阶段时均会产生高频区间的振幅峰值突起，预示梁体内部钢筋屈服、结构进入破坏失稳阶段，以此可作为声发射信号时频转换监测结构内部损伤程度的重要依据。更多还原

【Abstract】 To analyze the crack development characteristics of different reinforcement concrete beams during bending failure, and to explore the acoustic emission characteristics and bending performance degradation of the beams, a four-point bending test was conducted in combination with acoustic emission technology to establish the relationship between the bending failure process and acoustic emission signals of three different concrete beams. The experimental results show that the RA(rise time/maximum amplitude)-AF(average frequency) signals during the damage evolution of concrete beams with different reinforcements have obvious differences, the proportion of shear crack signal RA of reinforced beams, less-reinforced beams, and super-reinforced beams is much higher than the proportion of diagonal crack signal AF. The common characteristics of the amplitude distribution of bending damage at various stages of differently reinforced beams are mainly reflected in the amplitude peaks in the frequency bands 4～6 kHz, 13.5～16 kHz, and 53～57 kHz. When the beam reaches a certain load, the amplitude peaks in the high-frequency band will suddenly rise, indicating the yielding of the internal reinforcement of the beam and the entry of the structure into the failure stage. This can be used as an important basis for monitoring the extent of internal damage to the structure through time-frequency transformation of acoustic emission signals.更多还原