Preform and resin property uncertainities, role, and their effect in liquid composite process flow modeling

Physics based flow modeling provides an effective way to simulate and understand the resin infusion process in liquid composite molding processes and its variants. These are effective to provide optimal injection time and locations for given process parameters of resin viscosity and preform permeability prior to resin gelation. However, there could be significant variations in these two parameters during actual manufacturing due to differences in the resin batches, mixes, temperature, ambient conditions for viscosity; in the preform rolls, compaction, etc., for permeability. The influence of uncertainties in these parameters on the resin infusion time is investigated using resin flow modeling and statistical analysis. Application of the process flow modeling and statistical analysis to understand the effect of preform and resin property uncertainties is demonstrated via a composite helicopter prototype part processed via vacuum assisted resin transfer molding. The probabilistic modeling methodology resulted in confidence envelopes to determine the probability for successful resin infusion prior to gelation, and estimate resin infusion time for any combination of viscosity and permeability. The effectiveness of these confidence envelopes to determine the probability for resin infusion success and estimate the infusion time without a need for additional simulations and its usefulness for composite manufacturing engineers and technicians is presented.