Performance of Hybrid short beams with composite skins and titanium lattice cores: experimental and numerical validation

Hybrid composite sandwich panels with 3D-printed titanium lattice cores are very interesting for lightweight applications due to their exceptional strength-to-weight ratios. However, their in-plane flexural behaviour, whose relevance is usually neglected, requires thorough investigation. This study focuses on developing and validating a finite element model (FEM) to accurately predict the in-plane flexural response of a titanium lattice-cored short beam fabricated using Electron Beam Powder Bed Fusion (EB-PBF). The EB-PBF process, while enabling the creation of complex geometries, can introduce defects that significantly influence the mechanical behaviour of the lattice core. The developed FEM model incorporates the structural features to accurately capture the experimental observations. Furthermore, to achieve a deeper awareness of the failure mechanisms in these structures, micrographs were taken on the fracture surface of the tested specimens. This additional analysis gave valuable information about the relationship between the predicted in-plane flexural behaviour and the detected failure modes, allowing a more comprehensive understanding of the performance and limitations of these innovative lightweight materials.