Research on Damage of CFRP Inclined Angle Milling Holes Based on Acoustic Emission Signal and Axial Force Signal

Carbon fiber reinforced polymer (CFRP) has excellent mechanical properties and has been widely used in aviation, aerospace, and other fields. Due to the anisotropy of CFRP, it is prone to defects such as burrs and tearing during processing. Here, a method of processing hole damage identification based on the combination of acoustic emission signal and axial force signal is proposed. The two signals monitored during CFRP processing were analyzed through inclined angle milling experiments. The results show that the acoustic emission detection technology can monitor the processing damage of the composite in real time. Furthermore, the two signals can be used to identify and process burrs and tearing defects at the hole entrance and exit. The acoustic emission signals corresponding to each processing stage of inclined angle milling are analyzed. At the same time, the characteristics of acoustic emission signals at each processing stage are obtained. The acoustic emission signals of the entrance stage, the stable stage and the exit stage in the milling process are decomposed by wavelet. Then the fluctuation of the signals in different processing stages is obtained. The effects of different processing parameters on the burr damage factor and the root mean square (RMS) value of the acoustic emission signal are obtained by experiments. Ultimately, the size of the damage at the entrance and exit of the processing hole is assessed based on the two signals.