Architected Multimaterial Lattices
with Thermally Programmable Mechanical Response

(a) Multimaterial triangular lattice composed of an active material (green), which substantially weakens upon heating, and a passive material (black), whose mechanical response is temperature independent over the experimental conditions of interest. (b) Stress-strain response as measured in experiments (dashed line) and predicted by FE simulations (solid line) at T=23°C (blue lines) and T=100°C (red lines). (c,d) Numerically predicted deformation at e =2.8% and T=23°C (c) and T=100°C (d). (e) The stiffness of the lattice at high temperature can be programmed by varying the edge length of the triangular cells, l*, made out of the passive material. (f) Evolution of E* as a function of l* and r at T=100°C. At room temperature E=0:01739 irrespective of l*. [Note: The color in all numerical snapshots (c-d) corresponds to the normalized von Mises stress.]

A team at the Harvard MRSEC led by Lewis and Bertoldi has developed a versatile framework to realize thermally programmable lattice architectures capable of exhibiting a broader range of mechanical responses is reported. The lattices are composed of two polymeric materials with disparate glass transition temperatures, which are deterministically arranged via 3D printing. By tailoring the local composition and structure, architected lattices with tunable stiffness, Poisson’s ratio, and deformation modes controlled through changes in the thermal environment are generated. The platform yields lightweight polymer lattices with programmable composition, architecture, and mechanical response.

Publication:
J. Mueller, J.A. Lewis, K. Bertoldi, "Architected Multimaterial Lattices with Thermally Programmable Mechanical Response," Advanced Functional Materials, 2105128 (2021)

Jennifer A. Lewis (Material Science & Bioengineering) and Katia Bertoldi (Mechanical Engineering)
2021-2022 Harvard MRSEC (DMR-2011754)