Experimental analysis on delamination damage by acoustic emission in high speed drilling of carbon fiber reinforced plastics

Carbon fiber reinforced plastics (CFRP) has increasing applications in aerospace and other fields, due to low density, high strength, high stiffness, great resistance to corrosion, etc. Although, delamination damages in drilling holes for assembly influence the final characteristics of CFRP components. This paper presents an experimental investigation to analyze delamination damage, in which acoustic emission and thrust force are monitored during drilling CFRP laminates to clarify the relationship between AE signals and delamination damages. The results show that delamination damage has close correlation with thrust force and acoustic emission energy. AE root mean square (rms) is recommended to be selected as AE signal parameter. Abrupt peak feature of AE rms can be used as a dependable trigger for delamination monitoring. The number of abrupt pulses of AE rms can be counted online to predict the degree of delamination damages, based on which delaminations can be monitored and controlled online.