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为研究钢筋与混凝土间的粘结滑移特性,分别对不同粘结长度的钢筋混凝土试件进行了拉拔试验,同时对粘结长度相同而钢筋外形不同的试件进行了比较试验。利用声发射技术采集相应波形信号,并对采集信号进行了小波去噪和Gabor小波时频分析。结果显示,各试件受力全过程均可分为完全粘结、局部脱粘、非线性滑移及残余粘结四个阶段;不同粘结长度下的粘结滑移特性有所不同,其AE能量分布亦可反应该特性的变化;而钢筋外形不同的试件其粘结滑移特性有较大的区别,但不同试件在同一受力阶段,其声发射信号的时频特性基本相同。该研究同时得到了对应于构件宏观损伤和失效两个预警信号的声发射特性。
In order to study the bond-slip characteristics between steel bars and concrete, the drawing tests were carried out on concrete specimens with different bonding lengths respectively. At the same time, the specimens with the same bonding length and different reinforcing bars were tested. Acquire the corresponding waveform signal by using acoustic emission technology, and carry out wavelet denoising and Gabor wavelet time-frequency analysis on the collected signal. The results show that the whole process of each test piece can be divided into four stages of complete adhesion, partial debonding, non-linear slippage and residual adhesion. The bond-slip characteristics under different bonding lengths are different. AE energy distribution can also reflect the change of the characteristics; while the different shape of the bar specimens bond slip characteristics are quite different, but different specimens in the same stress stage, the time-frequency characteristics of acoustic emission signals are basically the same . At the same time, the acoustic emission characteristics of two early warning signals corresponding to the macroscopic damage and failure of the component are obtained.