Researchers demonstrate wider control of stiffness in engineered materials

Researchers reporting in Nature demonstrated engineered materials whose directional stiffness can be tuned beyond the range of three conventional structures used for comparison. Their design varies the lengths, thicknesses and connections of structural struts across orders of magnitude, using two governing parameters. Simulations and compression experiments showed that changing the architecture altered directional stiffness at constant density. The team fabricated centimetre-scale polymer specimens using 3D printing and also demonstrated finer structures using two-photon lithography. The polymer printing process achieved relative densities between 20% and 75%; lower fill fractions required the finer fabrication method.