Effect of temperature and pressure on structure and elastic properties of carbon fibers: a molecular dynamic study

Molecular dynamics simulations are used to study the effects of temperature and pressure on the structures and elastic properties of carbon fibers. The microstructures of carbon fibers at normal temperature and pressure are clearly characterized, showing good agreement with both MD simulations and experimental results. It is found that the elastic constants decreased with increasing temperature at relatively low pressures. However, at higher temperatures and pressures, the densification and reorganization of the carbon fiber structure led to an increase in elastic parameters. When the pressure exceeds approximately 15 GPa, the change in elastic constant C11 with increasing pressure decreased significantly due to the elimination of porosity. The results provided a reference for the design and application of carbon fibers under different temperatures and pressures.