Optimization of Complex Composite Monolithic Structures Using Cellular Core Tooling

Cellular core tooling is a new technology developed by JIT-inVision that has the capability to manufacture complex integrated monolithic composite structures.  This novel tooling method utilizes thermoplastic cellular cores as inner tooling.  The semi-rigid nature of the cellular cores makes them convenient for lay-up, but under autoclave temperature and pressure they soften and expand providing uniform compaction on all surfaces including internal features such as ribs and spar tubes.  This process has the capability of developing fully optimized aerospace structures by reducing or eliminating assembly using fasteners or bonded joints.  Double box beams were manufactured and sectioned into T-joints for characterization.  Mechanical behavior of T-joints was performed using the T-joint pull-off test and compared to traditional tooling methods.  Components made with the cellular core tooling method showed an improved strength at the joints.  In addition, a model has been developed using the COMPRO Common Component Architecture (CCA) plug-in for the Finite Element Analysis (FEA) software Abaqus to simulate temperature profiles, resin flow patterns and development of residual stress.  Model development has been carried out in conjunction with experimental validation.