Investigating surface effect on stress concentration in amorphous carbon materials with nano-scale pores: A molecular dynamics study

A Banna and S Roy, MECHANICS OF MATERIALS, 184, 104750 (2023).

DOI: 10.1016/j.mechmat.2023.104750

This article investigates the impact of nano-scaled pore on the mechanical properties of amorphous carbon (a-C) as a potential anode material for energy storage batteries, capacitors, and gas storage. Classical mechanics theory suggests that the surface tension caused by surface-bulk elastic mismatch can be used as a design parameter to offset stress concentration around pores and suppress crack growth. In this work we use molecular dynamics simulations to prepare and test 3D a-C specimens with cylindrical pores of varying radii to test this theory. Our results show a significant reduction in stress concentration factor from continuum prediction of 3 to a much lower value between 1.7 and 2.3, which can be attributed to local compressive hoop stress at the pore surface due to surface elastic mismatch in conjunction with nanoscale pore radius. These findings support the idea that pore size and shape can play an important role in improving the mechanics and strength of porous carbon materials, which could have significant implications for the development of high-performance energy storage devices.

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