Propagation characteristics of acoustic emission signals in engine hollow supports

Most of the supports in the engine are hollow structures. The hollow supports are the necessary paths for the internal acoustic emission (AE) signals to propagate to the shell. In this paper, the variation trend of amplitude and energy of AE signals with different frequencies in the propagation process of hollow supports are studied by numerical simulation and experiment. The amplitude and energy attenuation coefficients are proposed to quantify the propagation characteristics of signals. Through the pencil lead-break experiments, the spectrum analysis and the time-frequency domain analysis based on wavelet transform (WT) of AE signals in the propagation process are carried out. The results show that the tail end of the hollow support can converge and enhance the signals, and validated through experiments. This study demonstrates the propagation characteristics of AE signals in the hollow support structure, which helps to understand the signal propagation in complex structures and optimize the placement of AE sensors to improve the received signal strength.