Coupling of material point method and molecular dynamics for modeling ultrafast laser interaction with metals

Y Gan, ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS, 110, 104-111 (2020).

DOI: 10.1016/j.enganabound.2019.10.012

A hybrid numerical method that couples molecular dynamics (MD) with material point method (MPM) for atomistic simulations of thermomechanical responses of metals irradiated by ultrafast lasers is developed. In this coupled MD-MPM method, the MPM is used for the non- Fourier heat conduction in the electron subsystem of the heated metallic targets, and the lattice responses of the metals are described by the MD method with the inclusion of additional damping forces accounting for the energy transfer between the electrons and the lattice. The MD atoms are partitioned based on their topological relation with the MPM background grid and the MPM model for the electron subsystem are built with respect to the grouped atoms. The validity and robustness of the proposed MD-MPM scheme have been demonstrated through the representative examples for femto-/picosecond laser heating of metal thin films in one and two dimensions. Due to the inherent nature of the MPM, the presented MD-MPM algorithm could better handle the large deformations involved in the heated metals and be used for modeling the heating of metals by a wider range of ultrafast laser pulses as compared to the procedure combining the MD with the mesh-based methods.

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