Experimental validation of co-cure process of honeycomb sandwich structures simulation: adhesive fillet shape and bond-line porosity

Predictive models describing the co-cure process of honeycomb sandwich structures can increase manufacturing efficiency of aerospace structures by offering rapid, low-cost screening of viable combinations of material and process parameters. Honeycomb sandwich structures are co-cured to bond partially-cured thermoset prepreg facesheets with an adhesive layer to the core structure, during which multiple physical phenomena occur simultaneously. A physics-based predictive tool is developed to simulate this process by integration of sub-models for the adhesive bond-line fillet shape, facesheet consolidation process, and the porosity development within the bond-line, which, due to the coupling effects, is highly dependent on the former two phenomena. In this work, the experimental validation of both the individual sub-models and an integrated model for bond-line porosity is conducted. Despite the stochastic behavior of the co-cure process, the models successfully capture trends in adhesive fillet shape and the bond-line porosity, demonstrating their utility as tools for process screening to maximize the quality of co-cured parts.