MULTISCALE ANALYSIS ACROSS ATOMS/CONTINUUM BY A GENERALIZED PARTICLE DYNAMICS METHOD

作者：Fan Jinghong^*

来源：Multiscale Modeling and Simulation, 2009, 8(1): 228-253.

DOI：10.1137/080745407

• multiscale
• natural boundary
• particles dynamics
• inverse mapping
• nanowire

In this work, a GP method, short for the generalized particle dynamics method, is used to carry on multiscale analysis. The basic assumption of the GP method is that if the basic material structure can be kept the same as the real material at all scales, the multiscale analysis will be more accurate and more effective. Based on this assumption GP divides the simulation region into areas containing particles of different scales, n, where n = 1 is the atomistic scale and higher values of n correspond to the continuum scale. Natural nonlocal boundary conditions via material neighbor link cells are used for a seamless transition between domains of different scales. An inverse mapping method from the deformed particle domain beta(n) into the corresponding atomic domain an is proposed. All calculations of different scales can be conducted at the corresponding atomic an domain by the same potential, same parameters, same cutoff radius, and same numerical algorithm. The inverse mapping method is proved mathematically. Governing equations controlling the deformation transition between the particle and atomic domains of a one-dimensional model are derived. Numerical results show that the transition of deformation between the atomistic and particle domains is seamless under various nonuniform loading conditions. The initiation strain and detail evolution patterns of defects (dislocations) at different strain levels for a tensile copper nanowire predicted by the GP method agree well with those obtained by molecular dynamics (MD). The successful comparison indicates that GP, the extended MD method, has a great potential to be used in a large material domain.

• 出版日期2009