Titanium foams exhibiting auxetic pore structures are of interest for incorporation in sandwich panel cores due to their enhanced shear performance.
 Foams with this pore structure exhibit negative Poissons ratio in one or more dimensions. Poissons ratio is defined as the ratio of the lateral contractile strain to the longitudinal tensile strain for the foam undergoing uniaxial tension in the loading direction. Auxetic materials are typically able to resist indentations through their response to compression; upon compression, the auxetic material contracts. In addition to indentation resistance, research has shown that auxetic foams offer better absorption of sound and vibration, enhanced shear resistance and facture toughness. These structures also exhibit synclastic bending, which results lends itself to integration within curved sandwich panels.