[SY-E9] Atomistic Modelling of Fracture with Non-Linear Elastic Boundary Conditions
Atomistic simulations of crack propagation are key to understanding the fracture behaviour of materials. Cracks involve strong coupling across the scales, with bond breaking on the quantum scale driven by long range stress fields. Current QM methods are limited to simulation sizes too small to accurately describe fracture dynamics and improved QM/MM methods are able to adequately capture elastic effects [1]. However these methods are still heavily limited temporally and to coarse grain into the continuum scale while maintaining the overall fracture dynamics an expanded multiscale approach is required.
Applications in covalently bonded single crystals to complex alloys are underway. Screened classical potentials [2] predict a brittle response in both silicon carbide (SiC) and diamond, giving confidence in their applicability. DFT SiC surface energy calculations produced predictions in good agreement with experiment [3]. Extension of a multiscale approach for fracture includes a novel approach in correcting for finite domain boundary conditions, in which a non-linear continuum boundary correction is applied to help reduce the required system size, in order to compute energy barriers for crack extension bridging DFT and long time scale MD [4].
[1] N. Bernstein et al., Rep. Prog. Phys. 72, 026501 (2009).
[2] L. Pastewka et al., Phys. Rev. B. 87, 205410 (2013).
[3] G. Sernicola et al., Nat. Commun. 8, 108 (2017)
[4] P. Patel, L. Pastewka, C. Ortner and J. R. Kermode, In Prep, (2018)
Applications in covalently bonded single crystals to complex alloys are underway. Screened classical potentials [2] predict a brittle response in both silicon carbide (SiC) and diamond, giving confidence in their applicability. DFT SiC surface energy calculations produced predictions in good agreement with experiment [3]. Extension of a multiscale approach for fracture includes a novel approach in correcting for finite domain boundary conditions, in which a non-linear continuum boundary correction is applied to help reduce the required system size, in order to compute energy barriers for crack extension bridging DFT and long time scale MD [4].
[1] N. Bernstein et al., Rep. Prog. Phys. 72, 026501 (2009).
[2] L. Pastewka et al., Phys. Rev. B. 87, 205410 (2013).
[3] G. Sernicola et al., Nat. Commun. 8, 108 (2017)
[4] P. Patel, L. Pastewka, C. Ortner and J. R. Kermode, In Prep, (2018)