Abstract: Due to its high strength, high hardness, high toughness and high viscosity, SiC/GFRP laminated composite armor after molding has considerable difficulty in hole drilling. Damages such as laminat interface failure, ceramic chipping, and fiber tearing tend to occur during hole drilling. The novel thin-walled diamond core drill prepared by the hybrid process of sintering and brazing was used. Combined with rotary ultrasonic vibration technology assisting with hole machining, the kinematic model of a single abrasive particle was established, the core drill and the workpiece were separated by contact periodically during ultrasonic vibration drilling, and the discontinuous cutting characteristic is conducive to reducing the axial force. The hole-drilling experiments on SiC/GFRP laminated composite armor were conducted. The change law of the axial force and the hole quality in conventional machining and ultrasonic vibration-assisted machining were analyzed. The results showed that: compared with conventional sleeve grinding, the axial force in the case of ultrasonic vibration-assisted sleeve grinding was significantly reduced, with a maximum decrease of 31.8%; the bonding at the laminate interface during ultrasonic machining was tight and no serious ceramic breaking occurred; defects featuring irregular bulges and large bulge height in holes by conventional machining were effectively avoided, and the maximum reduction of bulge height was 61.03%, which significantly improved the surface quality of the holes and reduced the degree of hole damage. The results provide theoretical reference for the continuous hole machining in SiC/GFRP laminated composite armor with high efficiency and low damage.

Key words: SiC/GFRPlaminatedcompositearmor, rotaryultrasonicvibration, diamondcoredrill, holequality