Mechanically robust 3D printed elastomeric lattices inspired by strong and tough hierarchical structures

Abstract

Lattice structures have been proven capable of a wide range of engineering applications due to their complex design arrangements, such as periodicity, topology, and morphologies. Yet, developing a hybrid design is challenging due to limitations of node boundaries, material, and fabrication constraints for improving mechanical performance. To overcome these challenges, hybrid designs were developed here using the vat photopolymerization technique by grading the bend- and stretch-dominant strut morphology in parallel and perpendicular directions. Firstly, numerical simulations predicted the unit cell performances, and then the structural behavior of periodically arranged 3D-printed elastomeric lattices was also investigated. As a result, hybrid design provided a better performance strategy under high load conditions, including a significant amount of mechanical performance (7 times) than the uniform lattice topology. In addition, a vat photopolymerization-based 3D printing technique was investigated by introducing a high-loaded silica filler in the polymer, as a filler reinforcement exhibiting the advantages of enhanced stiffness (12 times) and reduced buckling to the lattices. Finally, the performance of hybrid-graded design was examined via filler-coated surfaces, which could provide insight into their ability to adapt to lightweight devices and engineering applications.