Experimental investigation of the three-point bending properties of sandwich beams with polyurethane foam-filled lattice cores

In the present research, the energy absorption and collapse behaviors of a rigid polyurethane foam-filled sandwich beam with expanded metal sheets as core were studied. Three types of steel lattice core, both unfilled and foam-filled, were subjected to the quasi-static three-point bending test. Force-displacement relationships, collapse modes of the beam, and the impact parameters, including absorbed energy, crashing force efficiency and Specific Energy Absorption (SEA) were discussed. Also, the impact of the direction of the lattice sheets in the core of the sandwich beams, both longitudinal and transverse directions, as well as the effects of the cell geometry on energy absorption, was further evaluated. It was found that the polyurethane foam reinforcement could enhance the energy absorption of the sandwich beam by up to 80%. The appropriate direction of the lattice sheets in the core could increase the energy absorption by 74.6%. The presented sandwich beam with the polyurethane foam reinforced lattice core due to high absorption capacity and lightweight structure could be implemented as an energy absorber in the aerospace, transportation, and elevator industries.