Bridging crack propagation at the atomistic and mesoscopic scale for BCC-Fe with hybrid multiscale methods

The hybrid multiscale method bridging the atomistic and mesoscopic scale is proposed in the current study, which combines the concurrent generalized particle (GP) dynamics method and the bottom-up hierarchical cohesive zone model (CZM) with embedded traction–separation law. The primary purpose is to transfer the GP-obtained physical parameters to the upper mesoscale finite element method (FEM) to investigate the meso- and microscopic crack propagation. The local fracture energy, stress and opening relationships under tension loading during steady-state crack propagation are extracted from the three-scale GP model. In this procedure, the scale duality technique is conducted using the GP analog, which can allow material to exist as particles via a lumping process and allows them to decompose into atoms at crack tips and interfaces. Crack extension resistance is detected by coordination vector (CV) snapshots, and energy release rates in the subdomain are used to evaluate the material behavior against the crack propagation when the current crack tip grows. Using the unique cohesive element length, four-scale tension specimen FE models are designed to reveal the accuracy of the intrinsic correlation between the atomistic and mesoscopic scale under a stress intensity factor to study the brittle body-centered cubic (BCC)-Fe fracture behavior. The result appears reasonable and encouraging.