Low-velocity impact properties of foam-filled composite lattice sandwich beams: Experimental study and numerical simulation

This paper studies the low-velocity impact properties of foam-filled composite lattice sandwich beams. The ef-fects of transverse and longitudinal lattice-web spacing, lattice-web thickness, foam density, foam thickness, impact height and impact position on the impact resistance of the sandwich beam were investigated. Experi-mental results showed that the failure modes of the sandwich beams mainly included buckling of lattice web, skin fiber fracture, interfacial delamination between skin and foam, shear failure of foam, foam indention, and foam crushing. With the reduction of the longitudinal lattice-web spacing, the maximum impact force increased by 136.92%, and the maximum vertical displacement decreased by 51.46% for the simply supported specimen. With the increase of the web thickness, the maximum impact force of the specimen increased by 33.40% for the specimen on the rigid support. Furthermore, a numerical model was built and parametric analysis (skin thick-ness, foam density, and boundary conditions) on the properties of the sandwich beam was also conducted. Parametric analysis showed that the energy absorbed by the foam of the specimen on the rigid support was 110.39% more than that of the simply supported specimen.