Research on subsurface damage in CFRP cutting using a bamboo rat lower incisor biomimetic tool

Carbon fiber reinforced polymer (CFRP) composites are widely used in aerospace and other advanced engineering fields due to their exceptional mechanical properties and performance advantages. However, during machining, CFRP is prone to defects such as burrs, tearing, and delamination. Modifying the tool rake face geometry and adding micro-textures on the tool surface can reduce machining damage to CFRP. The underlying mechanisms of these effects remain to be further investigated. First, the unique “crescent-shaped concave” structure of the bamboo rat’s lower incisors is utilized and applied to the rake face of the cutting tool for biomimetic tool design. The variable curvature configuration of the “crescent-shaped concave” structure can effectively reduce cutting forces, thereby mitigating subsurface damage. Furthermore, based on the depth data of the “crescent-shaped groove,” a depth-varying micro-texture is applied to the biomimetic rake face of the cutting tool. The study investigates the fracture and failure modes of fibers and matrices under cutting load conditions. A combined approach of finite element simulation and experiments is employed to explore the subsurface damage suppression mechanisms during the machining of unidirectional fiber-reinforced plates at 45°, 90°, and 135° orientations. Using the micro-textured cutting tool proposed in this study to machine unidirectional fiber-reinforced plates at 45°, 90°, and 135° orientations, the subsurface damage was reduced by 40.83%, 11.94%, and 43.62%, respectively, compared to conventional tools. While subsurface damage was reduced at all orientations, a significant reduction in subsurface damage was observed in the 135° unidirectional fiber-reinforced plate.