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| Frequency band energy characteristics of concrete acoustic emission signals during the damage process under uniaxial compression |
| LAI Yu-shu 1,2，XIONG Yan 1，CHENG Long-fei3 |
| 1. School of Electronic and Information Engineering, Chongqing Three Gorges University, Chongqing 404000, China；2. School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China；3. School of Civil Engineering, Chongqing Three Gorges University, Chongqing 404000, China |
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Abstract The acoustic emission (AE) test of a concrete specimen damage process under uniaxial compression is carried out in order to find more effective concrete work failure precursor criterions. The AE signal waveform data during the damage process are acquired directly by SAEU2S digital AE acquisition system. Then these signals at the different damage stages are processed by using FFT and wavelet packet transform respectively, finding out the frequency distribution rule and the frequency band energy change rule of the AE signals at the different damage stages. And the concrete failure mechanism is interpreted from the perspective of the relationship between AE signal frequency change and crack propagation. The frequency band energy distribution histograms of the acoustic emission signal at different damage stages are computed and drawn by using the energy calculation method of wavelet packet transform in Matlab, the energy percentage of the low-frequency band at [0-26]kHz and it’s change rule versus time are analyzed especially. Accordingly, an important criterion indicator that the low-frequency energy percentage above a certain threshold is the damage critical point is proposed. This rule can be used as the fracture precursor criterion of the stability monitoring and early warning for concrete works, also has theoretical guidance to evaluate the internal damage of concretes.
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Received: 01 November 2013
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2014, Vol. 33 
