Effect mechanism of plain-woven structure of carbon fiber on CFRP cutting

Carbon fiber–reinforced plastic (CFRP) is increasingly employed as structural components for aircrafts in aerospace. The plain-woven CFRP is more commonly used than the UD-CFRP. The machining-induced damages are easy to occur. The influence of the plain-woven structure on the cutting mechanism and the defects occurrence mechanism are seldom studied in detail. In this paper, the three-dimensional FEM model of plain-woven CFRP is established. The occurrence and propagation of the delamination are investigated. The results indicate that the stress concentrations are easy to occur at the junction of warp and fill bundles near the cutting position. The plain-woven structure can block the transfer of stress and the crack propagation. When θ = 90°, the damages of the fill fibers and the crack of the interface are easy to occur. When θ = 45°, the step-like fracture is formed in both of the warp and the fill bundles, especially in the fill bundles. Under the same cutting conditions, the exit delamination of the plain-woven CFRP is obviously less than that of the UD-CFRP. The delamination greatly increases with the increase of the feed speed. The delamination decreases with the increase of the cutting speed. The delamination is closely related to the instantaneous cutting position of the cutter.