(649i) Validating Coarse-Grained Models for Thermoplastic Weld Strength in Aerospace Composites

Predicting the mechanical strength of thermoplastic composite welds depends on validated, verified models of polymer chemistries that can access microsecond timescales and many tens of nanometers. Here we develop the Flexible Library of Organic Workflows and Extensible Recipes for Molecular Dynamics (FlowerMD) and demonstrate its capabilities for thermoplastic materials workflows. We focus on aerospace thermoplastic chemistries poly(phenylene sulfide) (PPS) and poly(ether ketone ketone) (PEKK), showing how to initialize packings of linear chains of atomistic, united atom, and more coarse representations, train coarse-grained potentials, and analyze the fusion bonding and tensile testing trajectories. We show the coarse models of both chemistries reproduce glass transition temperatures of experiments and united atom models and conclude with discussions of how entanglement dynamics vary with temperature and influence debonding pressure.