Prediction of failure modes and peak loads in lattice sandwich panels under three-point loading

In this study, the failure behaviour of lattice sandwich panels under three-point loading has been studied using a nonlinear finite element analysis. The failure mechanisms of lattice-cored sandwich panels can be classified in three modes; facesheet yielding, facesheet wrinkling and core shear. When the panel fails due to facesheet yielding or core shear, the evaluation of the strength of the lattice-cored panel can be undertaken in the same manner as that of a foam-cored panel. In contrast, when wrinkle-like deformation occurs in the facesheets, the failure load can be estimated from the buckling stress of the facesheet. The failure mode map for the lattice-cored panel with the coordinate system t_f /l and ρ_c ^*/ρ_s can be described by the analytical equations that predict the three failure modes. The failure mode map highlights the dominant failure modes for the lattice-cored sandwich panel based on the key design parameters t_f /l and ρ_c ^*/ρ_s.