Mechanical Properties of 3D-Printed Pentadiamond

TL;DR

This study investigates the mechanical behavior of 3D-printed pentadiamond, a new carbon allotrope, using simulations and testing, revealing scale-independent stress-strain behavior and promising energy absorption properties.

Contribution

It combines atomistic simulations and mechanical testing to characterize the mechanical properties and deformation mechanisms of 3D-printed pentadiamond, a novel carbon allotrope.

Findings

Stress-strain behavior is scale-independent.

Young's modulus decreases with more pores.

Structures exhibit high energy absorption, outperforming kevlar.

Abstract

In this work, We combined fully atomistic molecular dynamics and finite elements simulations with mechanical testings to investigate the mechanical behavior of atomic and 3D-printed models of pentadiamond. Pentadiamond is a recently proposed new carbon allotrope, which is composed of a covalent network of pentagonal rings. Our results showed that the stress-strain behavior is almost scale-independent. The stress-strain curves of the 3D-printed structures exhibit three characteristic regions. For low-strain values, this first region presents a non-linear behavior close to zero, followed by a well-defined linear behavior. The second regime is a quasi-plastic one and the third one is densification followed by structural failures (fracture). The Young's modulus values decrease with the number of pores. The deformation mechanism is bending-dominated and different from the layer-by-layer deformation mechanism observed for other 3D-printed structures. They exhibit good energy absorption capabilities, with some structures even outperforming kevlar. Interestingly, considering the Ashby chart, 3D-printed pentadiamond lies almost on the ideal stretch and bending-dominated lines, making them promising materials for energy absorption applications.