In our latest paper, soon to appear in a special issue of ASME Journal of Applied Mechanics dedicated to the mechanics of architectured materials, we present new results regarding the computational modelling of 3D auxetic lattices. ( https://doi.org/10.1115/1.4044542 )

These results have been obtained by Frédéric Albertini, in collaboration between PIMM and Monash University (Dr. Andrey Molotnikov).

The auxetic effect could lead to improved mechanical properties such as acoustic damping, indentation resistance, or crashworthiness. In this work, two 3D auxetic lattices are introduced. Auxeticity is achieved by design through pre-buckling of the lattice struts. The influence of geometrical parameters on the effective elastic properties is investigated using computational homogenization method with periodic boundary conditions. Effective Young’s modulus is 3D mapped to reveal anisotropy and identify spatial orientations of interest. The effective Poisson ratio is computed for various geometric configurations to characterize auxeticity. Finally, the influence of effective elastic properties on energy dissipation under compression is explored for elastoplastic lattices with different loading directions, using finite element simulations. Results suggest that loading 3D auxetic lattices along their stiffest direction maximizes their crashworthiness.