Strain rate dependent material removal mechanism and surface morphology formation mechanism for high strength CFRTP

Machining quality and efficiency are vital for the high-performance assembly of high strength CFRTP components. Strain rate sensitivity of thermoplastic matrix results in complex machining mechanism under the wide range of cutting speed. This study illustrates the strain rate dependent material removal mechanism for high strength multidirectional CFRTP (MD − CFRTP), and reveals the interaction between material removal behavior and surface morphology. Firstly, a mesoscopic orthogonal cutting finite element analysis (FEA) model considering strain rate effects is built. The deformation and fracture behavior under the influence of strain rate effect is illustrated via the FEA model. Then, the interrelationships between matrix plastic behavior, fiber elastic deformation, interface damage are revealed based on micro-morphology of cutting chips and FEA model. Finally, the strain rate dependent material removal mechanism is extended to the formation mechanism analysis of surface morphology. Results indicate that the evolution of fiber failure mode arise from the suppressed plastic deformation behavior of matrix at high cutting speed. The strain rate induced variation of material removal mechanism renders the difference of fiber pull-out mechanism, smearing matrix morphology, and surface morphology.