VERIFICATION AND VALIDATION OF A RAPID DESIGN TOOL FOR THE ANALYSIS OF THE COMPOSITE Y-JOINT OF THE D8 DOUBLE-BUBBLE AIRCRAFT

Polymer composite joints are critical aerospace components for reinforcing lightweight structures and achieving high eco-efficiency transportation standards. Optimizing complex structural joints is an iterative process. Fast and reliable numerical approaches are needed to overcome the runtime limitations of high-fidelity finite element (FE) modeling. This work proposes a computationally efficient approach based on the design tool, HyperX. Verification against FE models and experimental validation are presented for the composite Y-joint in the D8 double-bubble fuselage. Results show that the failure load of the Y-joint is predicted within 10% of the experimental failure load recorded. Two parametric studies are performed to study the effects of the curvature of the joint (110-160 deg) and the skin thickness (16, 24, and 32 ply) in the failure load predictions using a stress-based failure criterion. The maximum failure load occurred for a Y-joint with 130 deg curvature. The 32-ply skin Y-joint was predicted to have the highest failure load. Results prove the applicability of rapid joint optimization analysis for faster, computationally efficient design.