Abstract: Due to the different mechanical properties of carbon fiber and Kevlar fiber, the processing defects are easy to be induced during the machining of Carbon-Kevlar fiber hybrid composites (CKFH). These defects are more difficult to control than the processing defects of the single fiber reinforced plastics. Then, from the micro and macro perspectives, the three-dimensional finite element cutting models of CKFH are established. The cutting removal mechanisms of CKFH and the influence mechanisms of plain woven structure on the cutting process are analyzed. The results show that the Kevlar fibers are easy to be drawn into some filamentous, especially when the fiber orientation θ=0°/180°. When the fiber orientation θ=0°/180°, the form of chips is mostly curly sheet shape. When the fiber orientations θ=45°, 90°, 135°, the two kinds of fiber fracture affect each other, and the cutting surface and chip morphology are closely related to the cutting direction. When the fiber orientation θ=45°, most of the chips are fine flake chips, when the fiber orientation θ=90°, most of the chips are floccule chips, when the fiber orientation θ=135°, most of the chips are lumpy chips. When the cutter cuts the carbon fibers to the Kevlar fibers, the Kevlar fibers appear visibly loose and are drawn into some filamentous. Conversely, when the cutter cuts the Kevlar fibers to the carbon fibers, the carbon fibers in the Kevlar fibers ductile bending zone are brittle and broken by bending. Then, the pit phenomenon is prone to appear. The plain woven structure has an obvious blocking effect on the transfer of cutting stress. The finite element simulation results are basically consistent with the experimental observation results.

Key words: hybrid fiber reinforced composites, plain woven structure, cutting mechanism, finite element model