Finite Element Simulation of Crack Propagation for α-Ti Based on Cohesive Zone Law Deriving from Molecular Dynamics

摘要

In order to parameterize and obtain a traction-separation (T-S) law,molecular dynamics (MD) simulations via Large-Scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) are used at atomic scale for the deformation and fracture for models with dimension of 200(A)×204(A)×8.82(A) with crack for alpha titanium (α-Ti) with HCP crystal structure under tensile loadings at different loading directions.Visualization of the atomistic configurations during deformation is realized by use of ATOMEYE.It can be concluded that crack extension are correlate with the α-Ti crystal structure and crystal orientation intrinsically.We also found that HCP→BCC phase transition and twin deformation occur in the vicinity of the crack tip for HCP α-Ti under different loading directions via the common neighbor analysis (CAN).The complex mechanisms of deformation,i.e.,phase transition,twin deformation,and failure,i.e.,crack blunting and extension,were contained in the traction-separation (T-S) law.Then,the generated parameterized traction-separation law is implemented in the finite element model with the behavior of the CZM governed by traction-separation (T-S) law.Finally,the ABAQUS finite element commercial software is employed to simulate the crack propagation behavior for α-Ti CT specimen.