In acoustic emission tests, the effective signal generated by crack initiation and propagation inside a sample is easily affected by the testing machine, earth vibration and other external noise, which increases the difficulty of data processing and analysis. To solve this problem, a gypsum sample under uniaxial compression is taken as an example to analyze and process the acoustic emission signal during the experiment. The test results show that these noises generally have the characteristics of acoustic sources far from the probe and signal types different from the effective signal. Therefore, a series of methods concerning the noise reduction of acoustic emission signals, including acoustic emission signal preprocessing, acoustic source distance denoising, and acoustic source type denoising, is proposed. Through three analyses and treatments of acoustic emission parameters, noise reduction was achieved with good results. According to the principles of these methods, some suggestions have been put forward for the position of probes in acoustic emission tests; that is, the connection of two probes should not be perpendicular to a weak plane (bedding, joints, etc.). These results could provide a theoretical reference for the postprocessing of acoustic emission signals in mechanical tests.

中文翻译：

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声发射降噪：膏状岩石单轴压缩试验案例


声发射试验中，试样内部裂纹萌生和扩展产生的有效信号容易受到试验机、大地振动等外界噪声的影响，增加了数据处理和分析的难度。针对这一问题，以单轴压缩下的石膏样品为例，对实验过程中的声发射信号进行分析和处理。测试结果表明，这些噪声普遍具有声源远离探头、信号类型与有效信号不同的特点。为此，提出了声发射信号预处理、声源距离去噪、声源类型去噪等一系列声发射信号降噪方法。通过对声发射参数的三项分析和处理，达到了良好的降噪效果。根据这些方法的原理，对声发射测试中探头的位置提出了一些建议；即两个探头的连接不应垂直于薄弱平面（层理、接缝等）。研究结果可为力学试验中声发射信号的后处理提供理论参考。