Investigation on carbon fiber fracture mechanism of honeycomb composites in longitudinal‐torsional ultrasonic‐assisted milling processes

Abstract

AbstractA multi‐edge micro‐tooth longitudinal‐torsional ultrasonic‐assisted milling (LTUAM) model was established based on the hard brittle characteristics of carbon fiber honeycomb composites and the weak strength characteristics of the hole wall interface. The study analyzed the effects of ultrasonic characterization parameters on the cutting force, honeycomb wall width, and surface morphology. The results indicate that using LTUAM significantly reduced the cutting force and decreased the length and height of the burrs at an appropriate ultrasound amplitude. The spindle speed had the least impact on the width of the honeycomb wall, but increased with the longitudinal‐torsional ultrasonic amplitude and feed rate. The maximum error between the simulated and experimental cutting force values was approximately 19%. The longitudinal amplitude and torsional amplitude were 3 and 5 μm, respectively, the length of burrs decreased by 52.7%, and there was less delamination and tearing damage. LTUAM proved to be beneficial in improving cutting performance. Compared with conventional milling (CM), LTUAM resulted in regular fiber fracture morphology and smaller fragments on the honeycomb surface. In addition, the high‐frequency ultrasonic vibration promoted carbon fiber fracture and the surface roughness value under LTUAM was approximately 36.72% smaller than that of CM.Highlights Ultrasonic milling mechanism of carbon honeycomb is studied. Kinematic simulation of the tool of carbon honeycomb was studied during LTUAM. LTUAM promotes the fracture of carbon fibers. A multi‐edge micro‐tooth LTUAM model was established of carbon honeycomb. Deformation of the cell wall can be avoided by ultrasonic vibration of the cutter.