Tunable auxeticity and isotropic negative thermal expansion in three-dimensional lattice structures of cubic symmetry

A class of three-dimensional lattice structures of cubic symmetry is designed by spatially assembling and merging a number of two-dimensional re-entrant honeycomb structures. We demonstrate that the effective thermoelastic properties of these structures are widely tunable by tailoring the microstructural geometry and/or constituent materials. Particularly, they possess negative effective Poisson's ratios. If the inclined and non-inclined walls are of dissimilar thermal expansion coefficients, they can further attain isotropic negative or positive effective thermal expansion coefficients with a magnitude as large as several to dozens of times that of the constituent materials. Owing to these novel properties, they are well suitable as structural or functional components in engineering systems for preventing or harnessing thermal and/or mechanical deformation. (C) 2021 The Authors. Published by Elsevier Ltd.

Automated summary

The effective thermoelastic properties of three-dimensional lattice structures can be widely tunable by tailoring the microstructural geometry and constituent materials, exhibiting negative effective Poisson's ratios. If the walls have different thermal expansion coefficients, they can achieve isotropic negative or positive effective thermal expansion coefficients.