OPTIMIZATION OF PROCESS PARAMETERS DURING CO-CURE OF HONEYCOMB SANDWICH STRUCTURES

Honeycomb sandwich structures are co-cured to bond partially cured thermoset prepreg facesheets with an adhesive layer to both sides of the honeycomb core under a pre-defined pressure and temperature cycle in an autoclave. High dependency of the co-cure process on the materials and process parameters makes it susceptible to defect such as poorly consolidated facesheet and highly porous bondline which can cause premature failure of the structure. The temperature and pressure in the autoclave and pressure in the vacuum bag are the parameters that describe the cure cycle of the process. In this work, an optimization of the process cycle for the co-cure process of sandwich structures that maximizes the fiber volume fraction within the prepreg and reduces the porosity is presented. The objective function is constructed to reflect the quality of both the facesheet consolidation and bond-line porosity. The Surrogate Optimization Algorithm is employed to find the cure cycle resulting in the highest facesheet consolidation level and the lowest porosity within the bond-line.