Molecular dynamics simulation of propagating cracks

Atomic simulation of cracks under mixed mode loading

“…In fact, even under pure mode I loads the crack does not remain on the (010) plane at high load.levels. This behavior has been discussed elsewhere [26] and is probably related to the tendency of cracks in most materials to bifurcate at high crack speeds.…”

“…The general trends shown should, however, be fairly consistent. In this regard, the effect of model size under pure mode I loads has been studied [26] and was found to be very small. …”

“…The Johnson potential was chosen primarily because, as stated above, it has been used in a number of previous simulations so that its behavior in micromechanical studies is fairly well known. This model has already been shown to give reasonable predictions for the propagation of pure mode I cracks compared with experimental results on crack speeds and crack bifurcation [26].…”

Multiscale Modeling of Point and Line Defects in Cubic Lattices

“…Early work featured one-way [9][10][11][12][13][14] or two-way [15][16][17][18][19] coupled methods, in which displacement fields established at the interface between continuum and atomistic regions were computed either from sophisticated interfacial conditions or from initial conditions derived from continuum elasticity theory. Increases in computing power permitted more realistic two-way couplings, whereby atomistic fields were permitted to affect the far-field elastic continua through the latter's discretization with finite elements [20][21][22][23]. Such improvements in the coupling algorithms enabled description of dynamic crack growth [21].…”

“…Although some early work attempted to parameterize stress-strain relationships in the far-field region with atomic potentials [20][21][22], more efficient considerations of selected atomistic effects on material behavior were achieved through the initial developments of the quasicontinuum theory [26][27][28] that employed hyperelastic constitutive behavior, derived from atomistic potentials, for the overlaying finite elements. In the subsequent decade, significant new developments in methodologies have improved the fidelity of atomistically informed, continuum multiscale computational methods [29][30][31].…”