Multi-scale modeling of thermal and chemical kinetic characterization of composites during high-temperature pyrolysis by scale-bridging reactive molecular dynamics

Carbon nanotube reinforced phenolic resin composite shows great potential as thermal protection materials in the aerospace industry. To reveal its thermophysical characterizations and chemical kinetic mechanisms during high-temperature pyrolysis, a reactive molecular dynamics (RMD) simulation model is established to investigate the interfacial effect on the heat and mass transfer during the thermal pyrolysis of composites. A multiscale thermal pyrolysis model of carbon phenolic composites is further established with the varying thermophysical and chemical kinetic parameters input from the atomic-scale RMD simulation. The result suggests that the RMD investigation contributes both interfacial thermal pyrolysis mechanism revelation and comparable thermophysical characterizations, which can be the scaling bridge to upscaling analysis of composite thermal response, including the char layer evolution, during thermal pyrolysis at the macro scale. This multi-scale work provides an alternative approach of obtaining varying thermophysical properties during the high-temperature pyrolysis of composite materials with application in thermal response modeling at the macroscale.