Directional dependence and defect sensitivity of mechanical strength in twin irida graphene

Twin irida graphene is a novel two-dimensional carbon allotrope composed of interconnected 3–6–8-membered carbon rings, forming a bilayer structure with unique mechanical and electronic properties. In this study, we investigate the mechanical behavior of pristine and defective twin irida graphene using classical molecular dynamics simulations. The elastic modulus of the pristine structure is found to be directionally dependent, with values of 197.85 GPa along the x-direction and 179.63 GPa along the y-direction, indicating intrinsic mechanical anisotropy. Under uniaxial tensile loading, the ultimate tensile strength and toughness also exhibit directional dependence, with higher values observed along the x-direction. The presence of pre-existing cracks significantly reduces the load-bearing capacity, with crack orientation, length, and temperature playing crucial roles in determining the fracture behavior. Crack propagation follows a brittle-like failure mechanism, initiated by localized bond rupture at the crack tip. Furthermore, the mechanical properties degrade with increasing temperature, highlighting the sensitivity of twin irida graphene to thermal effects. These findings provide fundamental insights into the mechanical integrity and failure mechanisms of twin irida graphene, offering guidance for its potential application in flexible electronics, optoelectronic devices, and high-strength nanocomposites.