JOURNAL OF COMPUTATIONAL AND THEORETICAL NANOSCIENCE
Issue Date:
2013
Abstract(summary):
By means of molecular dynamics (MD) simulation, this paper explores the evolution characteristics of the cutting force and the microstructure inside the workpiece material during vibration assisted machining (VAM) of monocrystalline copper. The dislocation nucleation, propagation, annihilation and rearrangement inside the workpiece material are detailed, and the periodic characteristics of the dislocation evolutions and the shear band transformations, which may account for the periodic variations of the strain rate during VAM, are well revealed. A wavelet transform based multiscale analysis on the cutting force is conducted. Both the principal cutting force and the thrust cutting force involve deterministic trend components (DTCs) with periodic and nonlinear characteristics, and they also contain a class of disordered fluctuation components (DFCs) with high frequency. Statistical method is employed to investigate the randomicity of the DFC, which can be well described by a power-law distribution. The intrinsic dependence of the cutting force evolutions on the lattice structure variations inside the workpiece material has been clearly revealed. The localized plastic deformation in the form of shear strain with periodic characteristics may contribute to the DTC, the dislocation nucleation induced elastic instability and dislocation rearrangement may contribute to the power-law distribution of the DFC.