Comprehensive molecular dynamics study on mechanical characteristics of Net C under temperature, defects and geometric influences

This study provides an extensive molecular dynamics evaluation of the mechanical behavior of Net C, a recently synthesized two-dimensional carbon allotrope constructed from periodically arranged 4-, 6-, and 8-membered carbon rings. Using the AIREBO potential within the LAMMPS framework, we systematically examine the influence of temperature (1-1000 K), random vacancy defects (0.5%-3.0%), central pinhole defects, inequivalent lattice-site vacancies, and nanoribbon geometry on the tensile response of Net C along its principal X -direction and Y -direction. The results reveal strong mechanical anisotropy: Net C displays ductile deformation with distinct first and ultimate failure stages when stretched along the X -direction, whereas loading along the Y -direction produces a predominantly brittle fracture. Increasing temperature and defect density significantly reduce stiffness, strength, and strain energy, with Young’s modulus decreasing from 942.5 GPa (along X -axis) and 574.3 GPa (along Y -axis) at 1 K to 749.0 GPa and 492.1 GPa, respectively, at 1000 K. Random vacancy defects enhance ductility in the X -direction but markedly weaken tensile strength in the Y -direction, while larger pinholes and site-specific C1/C2 vacancies exacerbate stress localization and accelerate failure. Nanoribbon simulations further show that wider geometries provide greater stiffness, higher fracture resistance, and improved load distribution. Stress-distribution analyses consistently indicate that failure initiates at highly stressed carbon chains and propagates through ring-dependent fracture pathways. Collectively, these findings provide a detailed understanding of how thermal, structural, and geometric factors modulate the mechanical performance of Net C, offering valuable insight for the design and optimization of Net C-based nanoscale mechanical and electronic devices.