Investigation on fiber fracture mechanisms in rotary ultrasonic milling of carbon fiber composites

The carbon fiber composites are widely used in many manufacturing fields due to their superior mechanical. Rotary ultrasonic milling (RUM) technology as a promising method is introduced to machining these composites. However, the processing damage is still a common problem for assembly operations. These defects will reduce the surface service performance and the fatigue life of components severely. Fiber cutting angle is a crucial factor that affects the removal mechanism and machining defects of the carbon fiber composites. In this study, an investigation on the fiber cutting angle during RUM of the carbon fiber composites is conducted, and the corresponding theoretical model is proposed. Both RUM with longitudinal vibration (RUM-L) and with longitudinal-torsional vibration (RUM-LT) are studied. In order to compare the improvement of the fiber cutting angle between RUM-L and RUM-LT, a characterization coefficient is developed. The results indicated that the proportional factor between longitudinal and torsional amplitude b = 0.3 is most reasonable for fiber cutting. A new longitudinal-torsional ultrasonic machining system is developed based on this proportional factor. Finally, the pilot experiments are carried out to verify the theoretical model. Experimental results indicate that the fiber cutting angle is in good agreement with the analytical model for calculating.

Automated summary

An investigation on the fiber cutting angle during rotary ultrasonic milling (RUM) of carbon fiber composites is conducted, and a theoretical model is proposed. The research results indicate that a proportional factor between longitudinal and torsional amplitude b=0.3 is most reasonable for fiber cutting.