A Multiphysics Coupling for Evaluation of Effects of Local Boundary Conditions on Autoclave-Cured Composite

This paper presents a high-fidelity digital twin for an autoclave to predict the local boundary conditions for multiple parts and the resulting fabrication-induced defects. An efficient coupling procedure between the high-fidelity thermal-CFD model and the customized thermo-chemo-mechanical model is developed by exchanging the turbulent flow-induced, spatially, and temporally-varying HTC as a local boundary condition for the Abaqus model. This method replaces the computationally expensive “every-time-step” coupling procedure with an efficient “block-coupling” strategy that exploits the fact that, for the same part geometry and orientation, part position, flow angle, flow medium, type of tooling, and type of autoclave, the temporal variation of HTC is only dependent on the Reynolds number of the flow. A multiphysics modeling approach is constructed based on the predicted local boundary conditions of autoclave parts and an integrated heat transfer and cure kinetics model for the determination of residual stress and distortion of composite parts. Heat transfer and material distortion predictions from the model with the block-coupling strategy were validated with experimental results from NIAR’s autoclave facility using an L-beam assembly with and without a neighboring tool.