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Advanced Stiffened Panel Failure Analyses in HYPERSIZER
New analysis predictions are provided for stiffened panels to capture failure modes such as flexural-torsional buckling (FTB), compression, and shear incomplete diagonal tension (IDT) postbuckling based on NACA TN 2661. FTB is frequently the controlling failure mode for airframes, rocket launch vehicles, ship hulls, and rail cars. Postbuckling is a weight-reducing technique that allows the skin of a stiffened panel to initially buckle before reaching the required limit load and is allowed if reserve strength in the panel can be proven by analysis. However, postbuckling analysis is difficult and time consuming to do manually or with nonlinear FEA.
Features in HYPERSIZER:
Two Flexural torsional buckling (FTB) methods provided: Argyris and Levy
Compression post buckling based on iterative method for computing effective width, load redistribution, and updated margins of safety
Shear incomplete diagonal tension (IDT) postbuckling implementation of NACA TN 2661
Strains in the skin and stiffener are calculated using HyperSizer’s stiffened panel A, B, D matrices
Skin postbuckling effects feed into the FTB analysis for combined failure mode interaction
User can specify a percentage of limit load for which initial skin local buckling is acceptable
FEM is automatically updated with reduced postbuckled stiffness
All FTB and postbuckling analyses correlated and validated to test data and included in HVV documents
Method developed to apply to both metallic and composite structures
Processes thousands of load cases
Used during preliminary design optimization
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