Improved Composite Duct Design for Increased Safety Margin or Weight Reduction

Practical methodologies were developed in Phase 1 to efficiently design nonlinear composite ducts and panels with large anomalies and cutouts for buckling, will be verified in Phase II with a comprehensive test/analysis correlation program. The analysis system is automated and integrated into the ANSYS finite element code using its macro language capabilities, including parameterized shell and solid models of subject composite duct systems. Important features included in the analysis system are 1) geometric nonlinearity of panels due to initial or load induced curvature, and 2) buckling and snap-through. Testing includes braided/RTM composite fundamental property samples, half scale JSF bypass ducts, and full scale JSF flange segments.