Investigation of Nanoscale Scratching on Copper with Conical Tools Using Particle-Based Simulation

In this study,a modeling approach based on smooth particle hydrodynamics(SPH)was implemented to simulate the nanoscale scratching process using conical tools with different negative rake angles.The implemented model enables the study of the topography of groove profiles,scratching forces,and the residual plastic strain beneath the groove.An elastoplastic material model was employed for the workpiece,and the tool–workpiece interaction was defined by a contact model adopted from the Hertz theory.An in-house Lagrangian SPH code was implemented to perform nano-scratching simulations.The SPH simulation results were compared with nanoscale scratching experimental data available in the literature.The simulation results revealed that the normal force was more dominant compared to the cutting force,in agreement with experimental results reported for a conical tip tool with a 60°negative rake angle.In addition,the simulated groove profile was in good agreement with the groove profile produced in the aforementioned experiment.The numerical simulations also showed that the normal and cutting forces increased with the increase in the scratching depth and rake angle.Although the cutting and ploughing mechanisms were noticed in nano-scratching,the ploughing mechanism was more dominant for increased negative rake angles.It was also observed that residual plastic strain exists below the groove surface,and that the plastically deformed layer thickness beneath a scratched groove is larger for more negative values of the tool rake angle and higher scratching depths.