Flaw nucleation in a brittle open-cell Kelvin foam

Open-cell Kelvin foam is considered as a spatial lattice consisting of brittle elastic struts rigidly connected to each other at the nodal points. The lattice is subjected to remote uniaxial tensile loading, an initial imperfection is introduced and sequential break of the struts is observed. Different loading directions and material densities are examined and it is found that the broken struts form a plane flaw, which may be either a bridged or a usual crack. The possible crack propagation planes to be used in the fracture toughness analysis are determined.