Additively manufactured, thermomechanical metamaterials for adaptive heat transfer

Abstract An additively manufactured, thermomechanical metamaterial (TMM) concept is introduced and demonstrated. The TMM is a polymer lattice hosting copper elements, in which mechanical strains on the lattice induce or release contact between the copper elements. The copper elements are designed and arranged so that their contact patterns create directional solid conduction pathways. The lattice and elements are digitally designed and 3D printed, so that TMMs can be readily optimized to meet requirements. Heat transfer experiments are undertaken by mounting TMMs in a two-axis strain-controlled configuration, resistively heating boundary elements, and imaging the TMM using infrared thermography under changing strain conditions. The results show that the 3D printed metal elements achieve excellent conduction, and that contact resistance between elements introduces a measurable but surprisingly small impediment to conduction. TMMs are constructed that show the ability to switch between insulating and conductive states, while also steering heat in orthogonal directions. A final TMM demonstrates a complex conduction pathway and scaling to a 12.5 mm lattice pitch.