Finite element evaluation of fracture toughness and crack propagation in LB-PBF AlSi10Mg

Abstract

Fracture toughness properties of additively manufactured (AM) AlSi10Mg were explored computationally in this work. FE investigation of a previous experimental work on AlSi10Mg involving varying building directions was explored through critical crack opening displacement (COD), stationary crack method and extended finite element method (XFEM). Load-displacement curves for each of the varying build cases were simulated using COD method. The knife-edge displacements from the COD models were used in separately created stationary crack models to simulate the J resistance behaviour of the models. The simulated J curves could capture the anisotropy due to the varying build conditions, and the fracture toughness values correlate well with experimental results. Further, XFEM models were created at specimen scale and a meso-scale, respectively, using a 'sub-modelling' approach. The meso-scale model could legitimately predict the crack path reported in the literature for similar build conditions. Also, a better understanding of the crack propagation behaviour in AlSi10Mg was achieved. A novel modelling strategy was established which could help in future for AM designs.