Multi-Sensor Detection and Estimation of Gaps When Drilling CFRP Composite Stacks

To avoid the uncertainty of the presence of gaps between CFRP stacks and to eliminate the inspection for gaps after every drilled hole, a novel approach for on-line gap detection and estimation when drilling CFRP composite stacks through various signal profiles was proposed. Experimental investigation of the proposed method was conducted using thrust force, vibration, acoustic emission, and audio signals, which were collected using dynamometer, accelerometer, acoustic emission sensors, and an air-coupled audio microphone respectively. A predetermined gap was introduced between the stacks of CFRP plates in the investigation. The results from this experimental study reveal the potentials of the proposed approach for on-line detection and estimation of gap when drilling CFRP composite stacks.