Residual ultimate strength assessment of stiffened panels with locked cracks

• The residual strength of cracked stiffened panels subjected to compressive loading is analyzed.
• The influences of the length and the orientation angle of cracks are investigated.
• The finite element model has two bays in the longitudinal direction with periodical symmetrical boundary conditions.
• The crack in panels causes a significant stress concentration around the crack tip.
• The ultimate strength of cracked panels decreases with increasing the aspect ratio.

The residual ultimate strength of stiffened panels with locked cracks under axial compressive loading is analyzed. The influences of various geometrical characteristics of cracks and panels, such as the length and the orientation angle of cracks, are investigated by the nonlinear finite element analysis. The cracks are prevented from further propagation by holes with a diameter of 2 mm drilled at their tips. The finite element model has two bays in the longitudinal direction, employing periodical symmetrical boundary conditions at the ends of the loading edge. Beam tension test results are used to define the true stress–strain relationship of the material, which is used in the FE analyses to account for the nonlinear material property of steel.