Effect of geometrical parameters on compression performance and energy absorption of pyramidal thin-walled tube core sandwich panel

Sandwich panels with pyramidal cores made of thin-walled tubes absorb energy very well, but their main limitation is the complexity of producing such a structure. This study utilized a novel self-interlocking assembly technique to fabricate the lattice core, significantly reducing fabrication time and material requirements. Experimental tests and finite element analyses were performed to investigate the effect of geometrical parameters on the out-of-plane characteristics of sandwich panels with pyramidal thin-walled tube cores and relative densities ranging from 1.39% to 3.96%. Finite element predictions for deformation mechanisms, compressive strength, and energy absorption match experimental results. The results reveal that the proposed approach for producing the nodes worked successfully, with no brazed nodes breaking. The amount of energy absorbed per unit of mass reduces by 22% and 27%, respectively, when the slenderness is increased from 3 to 5 and subsequently from 5 to 7. In addition, when the angle of the tubes is increased from 50 degrees to 55 degrees, it makes them 23% stronger and absorbs 13% more energy per unit mass. Regarding strength and energy absorption per unit volume, pyramidal thin-walled tube cores are better than traditional lightweight sandwich panels, especially at lower relative densities.