Modeling of Crack Propagation in 2D Brittle Finite Lattice Structures Assisted by Additive Manufacturing

The failure characteristics of lattice structures are of significant importance in various lightweight applications such as aerospace and biomedicine. In this study, several 2D lattice structures with different number of unit cells that represent different geometrical characteristics and deformation mechanisms were investigated for their fracture behaviors. The fracture characteristic of the cellular samples was studied experimentally through tensile testing. The fracture propagation patterns of different lattice designs were investigated by high-speed camera, and consequently analyzed via analytical model in order to evaluate the effect of finite unit cells on the fracture characteristics of these cellular structures. The results were further compared with the classic cellular fracture theory by Gibson and Ashby. The comparison results suggest that for small number of unit cells designs the homogenized fracture model does not provide accurate crack propagation predictions.