Mechanical and energy-absorption properties of schwarzites

Abstract

We investigated through fully atomistic molecular dynamics simulations, the mechanical behavior (compressive and tensile) and energy absorption properties of two families (primitive (P688 and P8bal) and gyroid (G688 and G8bal)) of carbon-based schwarzites. Our results show that all schwarzites can be compressed (with almost total elastic recovery) without fracture to more than 50%, one of them can be even remarkably compressed up to 80%. One of the structures (G8bal) presents negative Poisson's ratio value (auxetic behavior). The crush force efficiency, the stroke efficiency and the specific energy absorption (SEA) values show that schwarzites can be effective energy absorber materials. Although the same level of deformation without fracture observed in the compressive case is not observed for the tensile case, it is still very high (30-40%). The fracture dynamics show extensive structural reconstructions with the formation of linear atomic chains (LACs).

Mechanical Properties of Diamond Schwarzites: From Atomistic Models to 3D-Printed Structures

“…Previous works have already explored the energy absorption capabilities of TPMS-like materials. 4,34,[55][56][57] 3…”

Mechanical properties of 3D printed macroscopic models of schwarzites

“…This early collapse may be the result of the higher density of structures −688. [ 39 ] The region highlighted with B is a plateau after the elastic region, characteristic of energy absorption in the breaking layers that these structures have, and were discussed by Sajadi et al. [ 5 ] Note also that the experimental results for −688 and −8bal are grouped, with −688 showing higher stress values.…”

“…It represents a good compromise between computational cost and quality results. [ 66–68 ] Unlike previous works that used periodic boundary conditions, [ 5,39 ] all simulations were carried out using a finite box to mimic the loading conditions on the testing of the 3D‐printed macroscopic structures. The box was large enough to contain all the atoms, to avoid spurious replica interactions, and to avoid the suppression of lateral deformations.…”

“…They consist of Primitive (P), Diamond (D), and Gyroid (G) TPMS families, decorated with carbon, firstly proposed and studied by Mackay and Terrones. [ 29 ] Previous research demonstrated that schwarzites structural stability, [ 30–36 ] unique mechanical, [ 37–40 ] electronic [ 41–47 ] and thermal properties [ 48–50 ] are mainly determined by their negative Gaussian curvature. However, the vast majority of studies dedicated to schwarzites are theoretical.…”

“…688 indicates that each six‐membered ring is shared between two eight‐membered ones, while 8bal indicates the presence of eight‐membered rings, where the surface divides the structural space into two subdomains of equal (or balanced) volumes. [ 39 ]…”