Fuselage Window Cutout Stress Study
MSC Patran/Nastran, CATIA V5
Overview
Developed a global-to-local finite element workflow to evaluate stress concentrations at a fuselage window cutout under cabin pressurization. Far-field loads from a global fuselage model were applied to a simplified local panel model to analyze stresses around the window.
Technical Snapshot
Structure
Pressurized cylindrical fuselage section
Loading
Cabin differential pressure 8 psi
Global Model
Shell skin with beam frames and rod stringers
Local Model
Skin panel with window cutout and simplified frame/stringer representation
Stress State
Biaxial membrane (hoop and longitudinal stresses)
Scope of Work
• Built fuselage GFEM using shell, beam, and rod elements
• Applied cabin pressurization to generate membrane stresses
• Verified stresses using thin-cylinder analytical calculations
• Modeled local skin panel with window cutout in CATIA
• Applied force-consistent boundary conditions from GFEM
• Evaluated stress concentrations at window corners
Outcome
The local model reproduced the biaxial fuselage membrane stress state from the global model. Peak stresses occurred at the window corner radius, corresponding to a stress concentration factor of Kt ≈ 2.5 relative to the far-field hoop stress. The results were consistent with expected thin-shell cutout behavior and demonstrated the influence of stiffener load sharing and local geometry on stress distribution.