A delamination prediction model in ultrasonic vibration assisted drilling of CFRP composites

Carbon fiber reinforced plastics (CFRPs) are employed in many industrial applications because of their attractive mechanical and structural properties. However, to date, drilling is still considered as the most pivotal process in manufacturing/assembly of CFRPs components, and the delamination damage can be regarded as the most severe machining-induced issue in the drilling process. To solve this problem, a delamination prediction model for CFRPs using Ultrasonic Vibration Assisted Drilling (UVAD) with the abrasive diamond hole saw or core drill is proposed to calculate delamination factor and thickness. The approach of the modeling development starts from simplified for tool and CFRPs workpiece, calculating the total cutting force and the critical thrust force, respectively, and adopting maximum nominal stress criterion to predict delamination. Experimental validation has indicated that the calculated results showed a reasonable agreement with the experimental results on the basis of both delamination factor and thickness, proving the feasibility and the accuracy of the model. This work provides an important reference for selecting and optimizing the drilling parameters to enable delamination-free holes on CFRPs composite.