钢筋混凝土梁结构中的声发射波衰减传播特征

为了解距离对弹性波传播的影响规律，制作了两种不同规格的钢筋混凝土梁，通过断铅模拟声发射信号，利用PAC-3声发射系统对弹性波在钢筋混凝土中传播的衰减规律进行试验研究。结果表明：频率、波速及振幅均随传播距离增加整体上呈衰减趋势；弹性波在钢筋混凝土传播过程中，高频信号衰减程度大于低频信号，因而低频信号在长距离传播更稳定；波速及振幅在1.0 m处都出现了较大幅度的提高，经分析可知声波在经过混凝土三相交界处时会发生多次折射、反射、吸收衰减等现象，因而离散性增大。可见实际检测过程中的探头布置间距不宜超过1.0 m。

Research on attenuation and propagation characteristics of acoustic emission wave in reinforced concrete beam structure

The propagation distance affects the attenuation law of elastic waves, and the study of this law has practical significance for the health detection and monitoring of AE technology in reinforced concrete structures. In order to better fit the actual project, this paper produced two different specifications of reinforced concrete beams JL1.6 and JL2.0 on site, two each. By simulating the lead signal, the PCA-3 acoustic emission system is used to conduct an experimental study on the attenuation characteristics of elastic waves propagating in reinforced concrete. The research results show that: the frequency, wave speed and amplitude show an overall attenuation trend with the increase of the propagation distance; in the process of propagation in reinforced concrete, the attenuation degree of high-frequency signals is greater than that of low-frequency signals, and low-frequency signals are easier and stable in the long run. Distance propagation; the wave speed and amplitude have increased greatly at 1.0m, because the sound wave will undergo multiple refraction, reflection, absorption and attenuation when passing through the three-phase junction of concrete, and the dispersion will increase. Therefore, it is recommended that the probe arrangement spacing in the actual inspection process should not exceed 1.0m, and the arrangement should be combined with the actual site environmental conditions and economy.