(585c) High-Throughput Initialization and Simulation of Thermoplastic Fusion Bonding

Composites of carbon fibers embedded in thermoplastic matrices can be assembled into aircraft components without fasteners, but optimizing the mechanical properties of fusion-bonded thermoplastic welds requires an understanding of how atom-scale structure and dynamics influences centimeter-scale part reliability. We develop molecular dynamics simulation infrastructure for initializing and simulating the nanoscale fusion bonding dynamics of PEEK and PEKK polymers, making extensive use of MoSDeF.org tools and GPU-accelerators. Using mBuild, foyer, HOOMD-Blue, signac, and SMILES strings, we are able to simply and reproducibly initialize volumes of linear copolymers with controllable polydispersity, crystallinity, sequence, and with optional flat interfaces. We profile chain entanglement simulations on NVIDIA P100 and V100 GPUs, and find equilibration of million-atom volumes can routinely be performed in a couple of days. Using this high-throughput infrastructure, screening of weld strength (debonding pressure) as a function of temperature, time, initial crystallinity, and polydispersity can be performed, providing design rules for aerospace part fabrication.