依据瞬时频率的木材损伤过程声发射信号辨识

针对木材损伤断裂过程中声发射(AE)信号识别的问题,提出一种基于瞬时频率的AE信号辨识方法。首先,采用三点弯曲的方式对马尾松试件做损伤试验,利用采样频率为500 kHz的4通道NI USB-6366采集卡收集原始AE信号。然后,通过小波分析的方法对采集的原始信号降噪处理,并对降噪后的信号进行频率分析,再根据频率范围及产生原因的不同定义了两类AE信号。最后,通过Hilbert变换分别获得两类AE信号的瞬时频率,并统计两类AE事件频率。试验结果表明,基于瞬时频率统计的AE事件频率能够客观反映试件的应力水平,同时,木材损伤过程中主要产生断裂AE和变形AE信号,且断裂AE信号的频率范围明显高于变形AE信号的频率范围。

Acoustic Emission Signal Identification of Wood Damage Process with Instantaneous Frequency

In order to solving the problem of acoustic emission(AE)signal recognition in wood damage and fracture process,we put forward AE signal identification method with instantaneous frequency.Firstly,damage tests were carried out on Pinus massoniana specimens by three-point bending,the original AE signals were collected by using a 4-channel NI USB-6366 acquisition equipment with a sampling frequency of 500 kHz.Then,by using the method of wavelet analysis to the acquisition of the original signal noise reduction processing,and carries on the analysis of frequency of after the noise,according to different frequency range and causes of the two kinds of AE signals were defined.Finally,the instantaneous frequencies of two types of AE signals were obtained by Hilbert transform,meantime statistics and the density of two classes of AE events.The AE event density with instantaneous frequency statistics could objectively reflect the stress level of the specimen,and fracture AE signals and deformation AE were mainly generated in the process of wood damage,and the frequency range of fractured AE signal was significantly higher than that of deformed AE signal.