Negative Poisson’s ratio (auxetic) truss lattice metamaterials have recently emerged as highly effective reinforcements for brittle matrices, enabling strength and ductility levels that were previously unattainable. In this paper, we demonstrate how these architectures can be used to confine axially loaded structural elements, thereby achieving superior mechanical performance. We show that the enhancement arises primarily from exploiting the strain mismatch between the composite phases, which amplifies lateral confinement and induces higher hydrostatic stresses in the matrix. Experimental tests on high aspect ratio prismatic specimens confirm the reproducibility of this effect, extending prior findings from near-cubic samples to structural scale geometries. Through combined analytical and numerical studies, we quantify the differences between auxetic confinement and conventional schemes, and propose new predictive expressions for the load capacity of auxetically confined members. These results establish a direct link between reinforced concrete confinement theory and architected metamaterial design, opening new pathways for structural applications of auxetic lattices.
Vitalis et al. (Wed,) studied this question.