Experimental research on the matrix cracks and delamination distribution and their monitoring methods during drilling UD-CFRP

Although carbon fiber reinforced polymer (CFRP) has been widely used in various applications, it is still regarded as a kind of difficult to cut material due to its vulnerability to machining damages. In the current research, CFRP drilling experiments was conducted and found that the matrix cracks and delamination were observed not only at the entrance and exit of holes, but also in the middle area of the holes. Therefore, it is necessary to study the distribution of these defects due to the severe effect on the mechanical properties of CFRP. In this paper, the distribution of these defects as well as their monitoring methods were investigated. First, four factors were introduced to locate the distribution of these defects that were observed by X-ray CT scanner. Then, Statistical Process Control (SPC) was applied for damage detection with features optimized sensitivity analysis. Finally, the performance of SPC was validated, which has a high damage identifying accuracy of 86.78% and recommended for the on-line application.