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Coal rock stability evaluation has been proposed to predict the mine catastrophic hazards. Acoustic Emission (AE) as a useful nondestructive condition monitoring technique provides earlier fracture detection in coal rock. Due to various external and internal variables changings, AE events accurately characterized fracturing processes is still a problem. For this reasons, this paper proposes a new...
When rotor rubbing acoustic emission(AE) signal propagates in the complex structure, multi-mode waves have different propagate speeds and signals are distorted seriously because of the complexity of the revolving mechanical structure. The accurate AE source location could not be gotten using traditional time-delay estimation. On the basis of inversely attenuation between propagation energy and source...
Acoustic emission (AE) is a new approach to rub-impact recognition. The fuzzy entropy is introduced to analyze the effectiveness of the features, and the method of fuzzy comprehensive evaluation combining effectiveness analysis is proposed to acoustic emission recognition. Duration, average amplitude, maximum amplitude, dynamic range of amplitude and the first four nodes energies of the reconstructing...
Because of containing several model waveforms, the source rub-impact acoustic emission (AE) signal transmitting in complicated body would cause waveform distortion for varying transmission speed of each model and dispersion effect. It is difficult to distinguish useful AE from complicated mixture singals by traditional detect methods. To avoid the deviation caused by these factors,. A transmission...
When locating the rub-impact source of rotating machines by acoustic emission technology, precise time-difference of arrival is always not available to calculate the faults location due to the deteriorated signal correlation relationship among different sensors. This is caused by both the dispersion phenomenon since the acoustic emission signal includes various waveform modes while each type of waveform...
It is difficult to recognise acoustic emission (AE) signal because of serious pollution by noise. Fractal dimension is a new method to describe the characteristics of AE signal. According to the complex computation and low precision of box counting dimension, correlation dimension and Katz dimension, an algorithm of logarithmic fractal dimension based on waveform length was proposed in this paper...
The new method for discrete fractional cosine transform is proposed, and it was introduced in acoustic emission signal enhancement. According to the characteristic of rub-impact acoustic emission (AE) signal from rotating machinery, two constructions are proposed to enhance AE signal, which based on three cycles discrete fractional cosine transform (FDCT3), and modified transform (MFDCT3). The experiment...
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