Multi-scale simulation for atomic oxygen erosion in low Earth orbit on polymer matrix by bridging reactive molecular dynamics and finite element analysis

Materials constituting satellites in the Low Earth Orbit (LEO) environment undergo degradation during missions due to harsh conditions such as cyclic temperature variations in high-vacuum, exposure to UV radiation, and collisions with highly reactive Atomic Oxygens (AO). Especially among those, AO collisions oxidize the surface and induce mass loss by generating volatile gases, leading to component failure. Reactive Force Field (ReaxFF) molecular dynamics simulations, capable of describing chemical reactions, have been continuously performed to evaluate the AO erosion resistance of surface materials in LEO. Previous molecular simulation-based studies, however, evaluated AO resistance qualitatively by utilizing constant particle Number, Volume, Energy (NVE) ensemble simulations, where temperatures rise to several thousand kelvins over tens of picoseconds, and such extreme temperature conditions were not directly compatible with physical conditions in LEO. Therefore, we aimed to develop a multi-scale AO erosion analysis bridging thermal Finite Element Analysis (FEA) with mass loss rate determined from the ReaxFF MD simulations. The overall thermal analysis was conducted over solar heat flux and surface radiation, while the ABAQUS Umeshmotion and Arbitrary Lagrangian-Eulerian (ALE) algorithm was adopted to analyze the surface recession of the model. The relation between erosion yields in given temperature conditions was calculated using constant particle Number, Volume, Temperature (NVT) ensemble, fitted as the Arrhenius equation form, and implemented to the FEA simulations.